Figure 1
Bull.Los Angeles Neurol. Soc.
Vol. 34: 73-105( No. 2, April,) 1969
THE OTHER SIDE OF THE BRAIN I:
DYSGRAPHIA AND DYSCOPIA FOLLOWING CEREBRAL COMMISSUROTOMY
JOSEPH E. BOGEN, M.D.*
I, DYSGRAPHIA AND DYSCOPIA FOLLOWING CEREBRAL COMMISSUROTOMY
Lateral specialization in left and right hemispheres is usually inferred from the effects of unilateral cerebral damage. It can also be demonstrated by testing the two hemispheres separately following their disconnection. This latter approach has been employed in recent years in testing a series of patients who have had cerebral commissurotomy to diminish the spread and severity of seizures (1-4). Psychological and neurological studies of these commissurotomy patients has elicited extensive new evidence clarifying the capacities of the neocortical commissures (5-27). One of the interesting manifestations of hemispheric specialization in these patients is an inability to write with the left hand coupled with disability in the right hand for copying geometric figures (5). This paper presents in more detail some observations on this phenomenon, followed by a discussion of some implications for an understanding of agraphia and of constructional apraxia. Part II will develop further the view that specialization of the left hemisphere for language is accompanied by specialization of the right hemisphere for other functions.
The commissural sections were done by Professor P. J. Vogel assisted by other members, including the author, of the Division of Neurosurgery of the California College of Medicine, (University of California, Irvine). In all cases the commissurotomy included division of the entire corpus callosum and anterior commissure at a single operation. Section of the psalterium is assumed to have been completed with division of the corpus callosum. In three patients the massa intermedia was also sectioned and in three it was found to be absent. The therapeutic outcome remains predominantly good and is summarized elsewhere (4). The patients were tested for their ability, with each hand, to write spontaneously and to dictation and to copy print, cursive writing and geometric figures. Further details of testing are included in the description of the results. Our first eight patients are briefly described (see Table 1 ) . They vary greatly in age, type of disease, and response to surgery. However, all of them were right handed, preferred the right foot, and had right-handed
TABLE 1.
The Other Side of the Brain. Part I.
Age at
operation
48
30
31
14
13
13
27
43
Duration of
left dyspraxia
(weeks)
>200
4-6
>200
16-20
10-14
2-3
2-6
>100
Duration of
dysgraphia
(w66ks)
>200
20-30
>200
~80
>100
8-16 2-8
>100
All patients had essentially the same extensive disconnection of the
cerebral hemispheres.
The accompanying illustrations were chosen to be representative of the
total material accumulated. But in retrospect, they may be misleading in a
specific detail. That is, in some cases the models which were drawn for
the patient to copy were discarded. Therefore, some figures (2a, 2b, 3, 4d,
5b, 8b, 8d) show models which were drawn, not at the time of testing, but
which were inserted for illustrative purposes at the time the figures
were assembled for this paper. The significance of this appeared only
after the introduction of standardized, printed models (since discarded)
when it became apparent that the ability to copy may be better if the
patient sees not only the final product, but also the production of the
model. Models used at the time of testing have therefore been included
where still available (figures 4b, 4e, Sa, 5d, 5e, 5f, 6, 7b, 8a, 8h, 9, 10).
The samples of writing and drawing have not been altered; however, in a
few instances it was necessary to trace over the pencil marks to darken
them in order to obtain adequate reproduction.
_
For most of the illustrations, the patients¹ products were cut out and pasted closer together for more economical reproduction; this seemed reasonable although it obscures such errors as closing in (28). In the interest of pre and postoperative comparison, figures 5a, 5d, 5e, and 5f are presented without any rearrangement. (See also 8h). Inability to write has been called agraphia ever since the term was introduced by Ogle in 1867. The term dysgraphia is used here to avoid the implication that the defect is 100 percent complete. For the inability to draw a figure, we used for several years the term adelinea (from the Latin delineo, to draw). Although this term has had the approval of a medical etymologist (J. E. Schmidt of Charlestown, Indiana), it does not clearly indicate that the defect is in following a visual instruction (that is copying a model) rather than drawing from verbal instructions. We have therefore adopted from acopia, as used by Critchley (29, 30), the term dyscopia, again to avoid the implication of a complete 100 percent defect. In order to avoid repeating throughout this paper the long expression ³the phenomenon of dysgraphia in the left hand and dyscopia in the right hand following cerebral commissurotomy², the abbreviation D-D will be used.
3. Eight Patients with Cerebral Commissurotomy
Case I
Case Summary: W.J. was a thirty-year-old man of normal development and
above-average intelligence at the time he suffered multiple head injuries
in World War II. A convulsive disorder developed subsequently, responding
poorly to medical management. He had a cerebral commissurotomy on
February 6, 1962 (at age 48). There was distinct atrophy of the right
frontal lobe. His case has been described in greater detail elsewhere (1,
2). He has continued free of convulsions but has remained on a full
disability pension. His most independent activity subsequently was a
series of cross-country plane trips in which he traveled by himself to
visit interested doctors, relatives and friends in several cities.
The inability to write with the left hand accompanied by inability to copy
with the right hand was reported in 1962 (5) and illustrated in 1965 (6,
7). These D-D symptoms continued with little change through 1966 and
1967 when tested on several occasions.
Description of Fig. !. (5 years post-op). With his left hand he drew what
looked as if it might be a ³P² and then stopped and shook his head. He was
asked what this was and said, ³I was trying to write my name (Bill).² He
was then asked to write something with his right hand and he wrote the
sentence in the upper right hand corner. He was then asked to attempt
again with his left hand and produced only the small scrawl which is seen
in the upper left-hand corner. He was then shown a model of the Greek
cross; he copied it with his left hand. The arrow which was added later
indicates that he started at the top of the figure and drew the entire
figure with a
single continuous line. He was then asked to copy the same model with his
right hand; he drew the strokes in the order indicated. He finished only the
first six strokes; he was then urged to continue and he added the seventh.
When persuaded to add some more, he put in the concluding three strokes
and then stopped. When asked if he was done, he said, ³Yes².
Comment.After the patient was sufficiently recovered from his operation
to be tested, it became apparent that he could no longer write with the
left hand although he could do so before operation (7). This was not only
true during that phase of the postoperative period when his left hand was
paretic and later severely apractic; but also long after the left hand was
functioning well. The dysgraphia therefore is not simply attributable to a
motor defect in the left hand.
Although the right hand was never paretic and could write well even in the
early postoperative period, it could not copy correctly even simple figures
such as a Greek cross. This difficulty was not attributable to a lack of
motor control (the lines were drawn firmly and with precision) but was
related to a defect in conception (the lines were in the wrong places).
As time passed there has been some improvement in the copying ability of
the right hand; but even after five years there persists (as shown in Figure
1) dysgraphia with the left hand and dyscopia with the right hand. It is
noteworthy that right-handed attempts to copy a Greek cross are more apt
to be defective on the left side of the figure, as is often seen in the faulty
productions of patients with right parietal lesions.
Figure 1
Case II
Case Summary: N.G. was born in the sixth gestation month, was in an
incubator for some weeks, and on leaving the hospital weighed five pounds
(2300 grams). In spite of this, she was considered normal in development
until she began having convulsions at the age of eighteen. Her condition
worsened as described previously (3) and she had a cerebral
commissurotomy on September 5, 1963 (at age 30). She needed help from
her husband the first year, subsequently assuming full management of her
household.
The D-D was apparent soon after surgery and was described in 1965 (7) at
which time it was apparently receding. However, when re-tested two and
a half years after surgery, it was again present (see Figure 2a). When retested
in September, 1967, the right hand not only printed and wrote well,
but also copied fairly well whereas in the left hand there was both
dysgraphia
and dyscopia (Figure 2b) .
Figure 2
Description of fig. 2a
(2 1/2 years post op): Although making a mistake in spelling, the patient
wrote readily with the right hand when she was asked, ³Please write the
date². In the lower left hand corner is shown her attempt to write, to
verbal request, the word ³dog², using her left hand.
The model cube was copied with the left hand as shown in the upper left;
it was attempted unsatisfactorily with the right hand as shown in the
upper right.
FIG. 2.
Description of fig 2b(4 years post op). The patient could write to dictation
(numerals) with both hands but an entire sentence was impossible for the
left hand. The writing with the left hand was done with a great deal of
arm motion from the shoulder. Left hand copying was generally poorer than
copying by the right hand.
Comment: Subsidence of D-D after six months in this patient was considered attributable either to the nature of her original disease (paranatal brain damage with consequently less lateralization of cerebral functions including language) or to the relatively less brain damage than in Case I, or because she was operated at a younger age than Case I. In retrospect, a fourth factor must be considered; namely, practice. Her improved performance six months after operation (7) came after she had been repeatedly tested and instructed. When she was re-tested 2l/2 years
post op, the D-D was again apparent (as shown in Figure 2a). This relapse to the original condition may be attributable to the fact that she had no occasion in the interim to either write with her left hand or draw with her right hand. Figure 2b was after a long period without left handed practice but the patient had been practicing with her right hand.
Case III
Case Summary: A.M. was considered normal until the age of fifteen when,
coincident with a head injury, he fell into a swimming pool and was
apparently anoxic for a time. He did not return to school but helped his
father at glass polishing for a while. Within a year he began having
generalized convulsions. As the convulsive disorder worsened, he
gradually developed severe incoordination of the legs which progressed,
even when medication was reduced, so that by the age of twenty-five he
was confined to a wheel chair.
When seen in June, 1964, (at the age of thirty-one) he appeared mentally
retarded but alert and cooperative; with either hand he could write legibly
Figure 3
FIG. 3.
and could copy various geometric figures. There was a gross ataxia of the legs associated with normal reflexes and impaired position and vibratory sense. The EEG showed a severe generalized abnormality and a pneumoencephalogram showed marked cerebral atrophy, most evident biparietally, more so on the right side. Following operation on July 7, 1964, he has rarely spoken, although remaining affable and interested in watching TV which is his principal occupation. He remains confined to a wheel chair. Description of fig. 3. About a year after surgery, the patient did not know the date, but he wrote it fairly well after being told. The left hand wrote only a scrawl (not shown). Given a model square, the right hand copied quite poorly, the left hand a little better.
Comment: Sometimes (as in Figure 3) the left hand seemed to copy a little better but more often it was just as bad as the right. As the years have passed his performance in most respects has gradually deteriorated. Although A.M. shows D-D in that writing was lost in the left hand and copying was lost from the right hand, he does not clearly show a superiority for copying
with the left hand. This is most reasonably ascribed to his overall
retardation and perhaps to the fact that his cerebral atrophy was more
evident in the right parietal region.
Case IV
Case Summary: A.A. was his mother s first child, the labor was induced
because of toxemia, and he was delivered by forceps fourteen hours later.
At the age of four months he had two convulsions associated with fever;
but he was thought to be developing normally until age five and a half
when generalized convulsions recurred, sometimes beginning in the right
arm. He
Figure 4ab
Fig.. 4A.
FIG. 4B.
began to fail in school in the fourth grade. Medical treatment did not
control the seizures; and he was operated on October 14, 1964 (at age
fourteen). The operation was difficult and included interruption of two
large bridging veins, causing right cerebral swelling. There has persisted
since operation a spastic left leg with a positive Babinski sign; but his
left arm recovered well. Since 1966 he has attended a day-school for the
handicapped where he has made a good adJustment.
A.A. could write legibly and copy geometric figures well with either hand
before the surgery (See Figure 4a). After operation, he copied very poorly
with the right hand although he could write well. When the left hand had
recovered from the postoperative paresis, it was able to copy much better
than the right hand even though he could not write with it (See Figure 4b,
4e). The D-D was still present though less evident, eighteen months after
operation (See Figure 4d). By two years after surgery, the patient could
write a little with the left hand and could copy with his right hand as well
as with his left.
Description of fig 4a (preop). Before surgery, A.A. copied the solid cube
reasonably well with each hand, but with more assurance with the right.
Writing with the left hand was legible. When asked why he dotted the ³e²
in ³left², he said, ³I don¹t know².
Description of Fig 4b (3 months post-op). Writing was done without effort with the right hand although he oceasionally misspelled words and sometimes showed poor spacing (in the upper right of the figure). When asked to write ³somethingî²with his left hand, he wrote his first name
Figure 4c
FIG.. 4C.
and stopped (upper left). When he was asked to write ³cat² he tried
several times, producing only scrawls having a vague resemblance to his
name (upper left). He copied the Greek cross well with the left hand,
retracing parts of the figure; attempts with the right hand were
unavailing.
Description of Fig.4c (3 months post-op). The solid cube was copied
reasonably well with the left hand but poorly with the right hand (two
attempts are shown at the lower right). However, he could do a phantom
cube with the right hand to verbal instructions (³draw a square-now draw
another square with its corner in the middle of the first square-now
connect the corners²).
Description of Fig 4d (I1/2 years post-op). The patient was asked to write
³something² with his left hand and after several false starts asked,
³What?² The word, ³cat² was suggested and he then wrote on the piece of
paper his first name, as seen in the upper left. The word ³cat² was
written in cursive on a separate piece of paper and his attempted copy is
shown in the upper middle. On another sheet, the word ³cat² was printed
and he copied this
with his left hand as shown in the upper right. Also shown are copies with
each hand of the usual models.
Comment: Although this patient¹s recovery was complicated by a stroke
disabling his left side, the left dysgraphia after recovery is again not
attributable to a motor defect since he could then copy fairly wel] (Figure
4b, 4e). It is notable that the left hand would write his name (Figure 4d);
this is probably indicative of right hemisphere function rather than
ipsilateral control by the left hemisphere since he was supposed to be
writing the word ³cat². It is particularly interesting that the ability of
the left hand to copy included block letters, but not cursive script (Figure
4d).
Although the right hand could not copy, it wrote well and, furthermore,
Figure 4d
FIG. 4D.
could draw a phantom cube to verbal instruction (Figure 4e). In conclusion,
this patient manifested the D-D to a striking degree in spite of factors
tending to reduce the degree of lateralization such as brain injury at birth
and youthfulness at the time of operation.
Case V
Case Summary: C.C. ³turned blue from mucus² on several occasions
postpartum, but after that seemed well until age eight when he began
having fights and began falling behind in school. At age ten his family
first noticed spells of speechlessness associated with turning of the head
toward the right. These spells occasionally included a fall and transient
loss of consciousness. In spite of medication, both the frequency of the
seizures and the severity of antisocial behavior progressed. On the verge
of institutional commitment, he had a cerebral commissurotomy on March
27, 1965 (at age thirteen). The commissurotomy, which was preceded by
electrocorticography
of the left convexity, was exceedingly difficult because of the unusual head position requiring excessive retraction and manipulation of the left hemisphere. The patient was mute for over three months. After returning home he has gotten along fairly well in a private sehool. Before operation C.C. could write legibly with either hand and, surprisingly, could copy even a cube model. He was persistently obstreperous; he had to be coaxed for every test and on every occasion he would scribble or draw something on top of the material being saved for illustrative purposes (Fig. 5a). During the first year after operation it was equally difficult to obtain data. However, on a particularly happy occasion, it was possible to document clearly the D-D (See Figure 5b). When retested two and a half years after surgery, he was much more cooperative (Figure 5e, d, e, f).
Figure 5a
Description of Figure 5a (pre-op). The patient was told, "Write the date and
under that write with my right hand". He did this as shown (upper right).
He was then asked to use his left hand to write his name and ³With my
left hand.² He did both (upper left).
He copied a model cube with his left hand in the space to the left of the
model and with his right hand to the right of the model. Immediately after
doing so he added another drawing (using his right hand) and then said,
³That¹s an airplane.²
Figure 5b
Description of fig 5b (5 months post-op). The patient readily wrote his
name with his right hand. He would not write anything to dictation,
including his name, with his left hand. He wrote the word ³Sunday² in
cursive with his right hand (not shown), but could (or would) not copy it
with his left hand. Then, after he printed the word ³Sunday² with his right
hand, he printed two letters with his left hand before turning away to
whistle at a passing nurse.
The triangles were attempted on several occasions: On each occasion he
did quite well with the left hand but he had trouble bringing himself to try
it with the right hand. After considerable coaxing he managed to draw the
figure which is shown.
In drawing the square, he again had to be coaxed repeatedly to do anything,
especially with the right hand. It should be noticed that the square drawn
with the left hand was done in two strokes, the first being three sides and
the second stroke immediately following to close the figure. With the
right hand, he made four separate strokes, each one separated by a
lengthy pause terminated only after further coaxing. In drawing the Greek
cross with the left hand, he used two strokes: The first was nearly
complete when he stopped and stared. When told, ³There is some more², he
completed the figure appropriately. With the pencil in his right hand he
fidgeted, refused, and finally drew one horizontal line. He was told, ²Well,
thatís a good start² and he drew two more lines in a single stroke. After
a lot more coaxing he then suddenly drew the remainder of the incorrect
figure in a continuous third motion.
When copying the cube, the left hand immediately drew strokes one (the
square on the face of the cube) and then strokes two and three to complete
the top of the figure. After a little more coaxing he then suddenly drew
the remainder of the figure with a fourth stroke. He did not want to try
copying the cube with his right hand. After extensive urging, ³Well, do
something, just make a mark², he took the pencil and made the five short
strokes with his right hand.
Figure 5cd
FIG. 5C.
FIG. 5D.
Descr1ption of fig . 5c (21/2 years post-op). With his right hand, he wrote the word ³hat² to dictation (upper left). To dictation, with the left hand he made only several scrawls (not shown). Still using the left hand, he was asked to copy his right-handed writing; he made a scrawl (upper left). After several practice efforts, he correctly copied my printing in block letters (upper right). He then copied correctly on the first trial my lower case printing (middle left). This was repeated several times. He was then asked to print the same word without a model and did it correctly (middle right). He then copied several times my cursive writing of the same word
Figure 5ef
FIG. 5E.
FIG. 5F.
(lower left). Finally, he was asked to write the word ³hat² without a
model; he printed it instead (lower right). ,
Description of fig 5d (2l/2 years post-op). On the first trial, in one
motion, he correctly copied the cross using his left hand.
Description of lig 5e (2Y2 years post-op). Attempts to copy the cross with
the right hand were slow, labored and unsuccessful.
Description of f9 5f (2Y2 years post-op). The left hand copy was done
first; it was successful and done quickly, but only after considerable
urging as he kept insisting, ³I can¹t do that-I can¹t even write with my
left
hand.² When he succeeded, he was told, ³See, you can do a lot better
than you think-now do it with your right hand². He very slowly drew a
square, paused, frowned, shook his head and handed back the pencil.
Comment: In spite of the early injury to the left hemisphere, language
remained lateralized to the left in C.C.; and like the other patients, he lost
the ability to write with his left hand when the left hemisphere,
controlling language, was disconnected from the right hemisphere,
controlling the left hand. At the same time, the left hand retained the
ability to copy. As in Case IV the left hand could copy printed letters to a
limited extent (Figure 5b and 5e). Since C.C. was the only patient to be
operated from the left side, his case is particularly important as evidence
against the possible proposal that the left hand loses writing while
retaining copying because writing is more sensitive to the operative
trauma. The persistence of the D-D in spite of his youth may be ascribed
to an inability of the damaged left hemisphere to assume the copying
function, although it is possible that intensive training might facilitate
its acquisition. The rapid acquisition of printing in the left hand during a
single half-hour session certainly suggests considerable unused capacity,
but of which hemisphere is not clear from these data.
Case VI
Case Summary: L.B. was his mother¹s third Caesarean delivery; he
weighed five pounds, was cyanotic and remained in an Isolette for eight
days. Childhood development was considered normal, except for persistent
enuresis. His first convulsion occurred at age three and a half, and these
spells became intermittently worse until operation on April 1, 1965, (at
age thirteen). His postoperative course was particularly smooth (he spoke
well the next day) and his progress continued since that time. He attends
public school, doing passable work except in the ³new math².
Before operation, L.B. wrote legibly and copied excellently with either
hand (his I.Q. of 115 exceeded all other patients except W.J.). In the first
week after operation he showed D-D, the data unfortunately not preserved.
This rapidly disappeared and testing since has persistently shown an
ability both for writing and for copying in each hand (Figure 6).
Description of fig. 6 (5 months post-op). At this time L.B. wrote well
with each hand (12). In Figure 6 are shown his copies with each hand of a
number of models which suggest a third dimension; he did them all
correctly except for the tetrahedron, which is better on the right.
Comment: The rapid recovery of both writing and copying may be partially
attributed to practice, since he has had continual instruction from his
parents and teachers, as well as repeated testing of his performanee on a
series of special tests which has been published at some length (9, 10, 11,
12). In addition, however, his higher general intelligence and lack of gross
brain damage are no doubt contributory as well as his youthfulness at the
time of surgery. As reported previously (9) he shows a high degree of
ipsilateral
control by each hemisphere, so that any tendency to D-D is overshadowed
by the ability of each hemisphere to control either hand. Recent tests of
this patient (27) in which the visual input was restricted to one or the
other hemisphere, thus eliminating contamination by ipsilateral control,
document clearly a right hemisphere visuo-spatial superiority.
Case VII
Case Summary: R.M. was born by breech extraction on a farm. After
maternal desertion he spent most of his childhood in an orphan home. At
the Home he had several head injuries and twice broke his right arm. So he
learned to write with his left hand. He was always backward in school (he
Figure 6
FIG. 6.
performed at a third grade level when tested at age fifteen). Convulsions
began at age twelve and persisted, to which fact he ascribed his never
having had a job. He was supported by Social Security and was able to live
by himself with help from neighbors and local police. On March 14, 1966,
(he was then 27 years old) he had an uncomplicated operation from which
he recovered rapidly. But he has remained in the rehabilitation hospital
because of a persistent memory defect; he cares for himself but cannot
handle money reliably.
Before operation R.M. wrote legibly and copied well with either hand (Fig.
7a). Following operation he largely but not entirely lost the ability to
write to dictation with the left hand; copying with the right hand was
distinctly inferior to copying with the left hand (See Figure 7b). It is of
interest that spontaneous writing in the left hand produced, and was
usually limited to, an attempt at his name (Figure 7c). After repeated
testing he re-acquired the ability in the right hand to copy a cube (Figure
7c).
Description of Fig .7a (pre-op). On the day before the operation R.M. wrote
and copied reasonably well with each hand.
Figure 7ab
FIG. 7A.
FIG. 7B.
Description of Fig .7b (S weeks post-op). The patient easily wrote with
his right hand to dictation; the upper left is his best with the left hand.
The Greek cross was reproduced effectively by each hand as shown. The
model cube was copied fairly well by the left hand (lower left) but the
right hand drew only a square. When the patient was asked, ³is it
finished?², he then retraced the square. He was told, ³It ís not done yet².
He then retraced the square a third time.
Description of fig 7c (2 months post-op). The patient was asked to write the day with his right hand and did so with ease (upper right). When asked to write ³somethingî²with his left hand, he laboriously printed a misspelling of his name (Robert). His left-handed attempts to write to dictation were unavailing. However, when the word, ³sun² was printed in block letters, he could copy it with his left hand and did this twice (lower left). Several of his copies with the right hand were good (including a copy of the solid cube, lower right).
Comment: R.M. acquired left handed dysgraphia after operation; but this was not as profound or consistent as most of the patients, perhaps because of his having learned to write with his left hand at an early age. This may, in addition, have interfered with normal lateralization to some degree and thus facilitated return of copying in the right hand. However, copying in the right hand returned only after repeated testing, so that practice is
Figure 7c
FIG. 7C.
probably responsible at least in part. In spite of the earliness of his brain injury (presumably at birth), and inspite of the early childhood training, R.M. showed quite clearly for a time the phenomenon of D-D.
Case VIII
Case Summary: R.Y. was the last of eight children; there was no
difficulty at birth, and he developed normally through age twelve. At age
thirteen he was struck by a car and was stuporous for about one-half hour.
At age sixteen he began having ³spells²; generalized eonvulsions began one
year later. He was never employed on a regular basis, although he
occasionally worked as a painter or mason tender.
Cerebral commissurotomy was performed on March 7, 1966, (at age fortythree).
The patient was talking the following morning, although speech
tended to be monosyllabic and lacked spontaneity for some weeks. Since
operation, he has returned to living with his relations, cares for his own
needs, and helps about the house.
R.Y. has consistently shown the D-D, as well as ability to draw to verbal instruction with the right hand (See Figures 8a-f) . Description of Fig 8a (11 days post-op). The patient no longer had forced grasping in the left hand; but he could not easily open and close it on request. He did copy a triangle with the left hand (middle line on the left)
Figure 8ab
FIG. 8A.
FIG. 8B.
but could not copy the Greek cross. Attempts to write with the left hand
were fruitless (upper left).
Although he wrote well with his right hand, his first attempt to copy a
triangle was incomplete-a later attempt was better. His best attempt at
copying the Greek cross with his right hand showed a defect on the left
side of the figure (upper right).
Description of fig .8b (3 weeks post-op). He continued unable to write
with the left hand although writing quite well with the right hand (not
shown). The Greek cross was copied satisfactorily with the left hand in
spite of persisting apraxia for verbally requested motions of individual
fingers. The
right hand misdrew the cross, with, as is often the case, the defect being
on the left side of the figure. One of several vain attempts to copy a
model cube with the right hand is shown in the lower right. The first
attempt with the left hand produced the figure in the lower left which is
incorrect because it is reversed, and because it is a phantom rather than a
solid cube; this may possibly be the result of his having been shown
several times the strategy mentioned in the description of Figure 4c.
Description of fig 8c (4 weeks post-op). The patient was first asked to
write with his left hand and produced nothing. He was then told, ³Write
the year², with his right hand, which he did. He was then asked to copy
what he had written, using his left hand; as shown in the upper center, he
wrote (with his left hand) his first name. In the upper left hand corner is
seen a left
FIG. 8C.
handed copy of the Greek cross; and in the upper right hand corner an
attempt by the right. The left hand copied the cube in a manner similar to,
but improved over that of the week before (Figure 8b). With the right hand
he has by this time acquired to some extent the strategy for a phantom
cube, although the copy is incomplete on the left side.
Description of figure 8d (7 weeks post-op). He was first asked to write
the date with his right hand, and did so. Although he was able to write a
dictated problem, he could not do the arithmetic correctly. When shown a
model of a stairway to copy, he did this very poorly with the right hand.
With the left hand he drew something which is similar to the stairway and
seems to involve the use of perspective.
Description of figure 8e (10 weeks post-op). When given the usual model
of a solid cube, he copied it fairly well with the left hand (upper left).
With his right hand he made a square and then some other lines (upper
middle).
When it was suggested that he add some lines at an angle he did that, but he could not seem to fashion a reasonable copy. The patient (using his right hand) was then told to draw a square, which he did (upper right). He was then told, ³Draw from the upper right hand corner a line halfway between vertical and horizontal². He did this; it is labeled ³5². He was then told to draw a line from the lower right hand corner, which he did. He was then told to draw from the upper left corner a similar line. He then drew the line labeled ³7² and was asked, ³Is that really in the same direction as the others?². He replied, ³Well, I guess not², and he then drew the line which is labeled ³8². He was then told, ³Connect the end of the line which you just drew to the end of the nearest line.², and he drew the line numbered ³9² . He was then told, ³Connect that point with the end of the line at the bottom.², and he drew the line numbered ³10². It thus
FIG. 8D.
appeared that he was able to draw a cube if he were given verbal
instructions.
He was then asked to copy the usual Greek cross with his right hand and he
attempted this as shown in the left hand column, second row, where it is
seen to be incomplete. After a series of instructions comparable to those
for the cube, he completed a Greek cross with his right hand for the first
time in many weeks of testing. He was then told to copy with his right
hand the model Greek cross; he did this as shown in the drawing on the
right hand side in the second row. The order in which the lines were drawn
is similar to the order in which the lines were drawn when he was given
verbal instructions.
The patient was then asked to copy with his left hand the Greek cross. It
can be seen (in the left hand column, third row) that he did this in a
different order from that which he used with his right hand. He was then
asked
to copy a model of a can with his left hand, and he did this readily. He was
then asked to copy it with his right hand and this inadequate copy is seen
in the right hand column, third row. When given verbal instructions, he
fashioned a reasonable faesimile of the cylinder (lower left). He was then
asked to
FIG. 8E.
copy the original model, and he did this with his right hand as shown in
the middle drawing of the bottom row.
After all of the above intervening, he was asked to copy the solid cube
again with his right hand. Although considerable time had elapsed since
his
product to verbal instruction (in the upper right hand corner) it can be seen that he successfully accomplished this (lower right hand corner). Furthermore, the lines in the copy were drawn in essentially the same order used when he was following the verbal instruction.
Description of figure 8f (7 months post-op). The patient had not been
tested, or done any practicing on his own, for nearly five months. He wrote
³right hand² with his right hand when asked. He was then asked to write
³left² with his left hand: He transferred the pencil to his left hand, which
proceeded to write his first name instead.
He was then shown the solid cube for a model, and the left hand drew a
Necker (phantom) cube. He was not criticized for this but was immediately
asked to use his right hand, which he did; but the attempt with the right
hand was a failure.
The Greek cross was done well with the left and not so well with the right
hand. A further trial on the solid cube was then undertaken with
instructions to ³Copy it! Copy it!²; this resulted in a fair copy with the
left hand. The right hand was again tried and again failed and then tried
again. This final attempt started well but was abandoned with the
statement, ³I just can¹t seem to do it.².
Description of figures 8g and 8h (28 months post-op). A pencil was placed
in his left hand and he was told, ³Write down the day of the week². He
replied, ³I can¹t do that². He was then told, ³Write something-anything².
He made some motions with his left hand and then said, ³I can¹t seem to
Fig. 8H.
write with it². He was then told, ³Well, just write the word ³cat². He
then wrote the printed letters ³yee² which are shown in the upper left of
Figure 8g.
The patient was then asked to write down the day and the date with his
right hand (the date is wrong). He was then told, ³Write somethinganything
². He wrote ³Pico Rivera² which is the name of the community in
which he lives; the capital ³R² is incomplete. He was then asked to write
the word ³cat² which he did correctly. Somewhat later in the examination
he was asked, ³Multiply twenty-three by thirty-four². Using his right hand
he wrote this problem on the paper in front of him and finished it
correctly.
In Figure 8h is shown the piece of paper on which a model was drawn and
on which he first made a copy with his left hand and then made a copy
with his right hand. It is apparent that even with the Greek cross, there is
a superiority of the left hand.
Comment: R.Y. is of particular importance since, with the exception of W. J., he is the only patient who can be presumed to have had normal
cerebral development through most of childhood. Furthermore, there was no evidence of gross brain damage, and both operation and postoperative course were without complication. It is particularly noteworthy that drawing acquired by the right hand to verbal instruction resulted in a style of performance easily distinguishable from that of the left hand.
4. Summary of Results and Further Comments
Following cerebral commissurotomy in our first eight patients, all of whom were right handed, there was dysgraphia in the left hand and dyscopia in the right hand. One patient showed D-D for less than a week (Case VI who was the youngest patient, had the least evidence of brain damage and who has postoperatively the highest degree of ipsilateral control). One patient had a rapid, partial recovery (Case VII, who learned to write left handed as a child). The most enduring D-D was seen in patients with presumably normal childhood development (Cases I and VIII) and two youngsters with early damage largely restricted to the left (language) hemisphere (Cases IV & V).
It could be argued that the present findings are mainly in persons having
early brain injury and therefore may not reflect the situation in persons
developing normally. However, the least persistent D-D was in patients
whose brain injury dated from early life, including Case II, Case VI, and
Case VII. In contrast, it was quite persistent in those patients who
attained relative maturity before being injured, such as Case I and Case
VIII.
It is also relevant to consider the effect of the extracallosal damage
inflicted at the time of operation. For example, Case I, Case III, Case IV,
and Case V each had a difficult postoperative period for various reasons.
But Case II, Case VI, Case VII, and Case VIII each had an essentially
uncomplicated course and each showed D-D. Extracallosal damage is
probably important in a specific way; that is, the less extra-callosal
damage, the more easily will each hemisphere exercise a significant
influence on the ipsilateral hand.
5. Dysgraphia and Dyscopia After Hemispherectomy
After cerebral commissurotomy, the left hand writes poorly if at all but it copies better than the right, to the extent that there is the usual lateralization of language to the left hemisphere. We should expect, therefore, that after a right hemispherectomy paralyzes the left hand, the patient should retain writing but lose copying; and the opposite should occur after removal of the left hemisphere. Experimental verification of this conclusion is not often available sinee the majority of patients having hemispherectomy are persons with defects dating from early life. However, there are occasions when a person having developed normally, has a hemispherectomy for a tumor which first appears in adulthood.
A Patient with Right Hemispherectomy. G.E. was 28 years old when she
first became aware of incoordination in the left hand. This progressed
over
several months to complete paralysis. A low-grade astrocytoma was
partially removed on May 14, 1966, from the right central area. Her left
arm was the same after surgery and her left leg gradually worsened so
that on September 26, 1966, she had removal by Dr. E. Beehler of the right
hemisphere, partially sparing the basal ganglia.
When seen on July 19, 1967, G.E. was an attractive woman with no
impairment of voluntary facial movement but some impairment of the left
side when smiling or frowning. She spoke excellently and was very quick
to understand the test procedures. She walked reasonably well, including
up and down stairs, with a short leg brace on the left leg and a cane in her
right hand. Her left arm was in spastic flexion but the hand could retain an
object placed in it. She wrote fluently with the right hand but could copy
only with
Figure 9
FIG. 9.
great effort (See Figure 9). She was fully aware of both her high verbal
intelligence and of her defect in copying, and at the conclusion of the
interview said, ³Just imagine how smart I would be if I had both halves of
my brain!².
Description of fig. 9 (10 months post-op). The patient was asked, ³write
the day of the week and the date², which she did easily and fluently. She
was then asked to copy a model of a cross (upper left). Her first attempt
was done quite slowly, and she finally abandoned it. On her second trial
she obtained a reasonable copy; this was done very carefully and
laboriously. She was then shown a model cube (upper right); and she copied
this very slowly and carefully, stopping after the line numbered 8. She
was then urged to continue, and she said, ³Well, I guess this will have to
be a house², after which she drew the line numbered 9, and a door. Because
it appeared that this copy was facilitated by verbal thought, a model of a
stairway was drawn for her while she watched (lower left); she copied
this slowly and with a great deal of effort and finally gave up saying,
³What a mess !².
A Patient with Left Hemispherectomy. E.C. was 47 years old when Dr. C.
W. Burklund removed his left hemisphere on December 7, 1965, because of
a recurrent glioblastoma. His case has been reported at length by Dr. Aaron
Smith (31, 32, 33) and was recently discussed by Zangwill (34).
Through the courtesy of Dr. Burklund and Dr. Smith, I can report this exam
on November 2, 1966, nearly a year after his hemispherectomy. He was
seated in a wheel ehair with his right hand in typical spastic posture
resting in his lap. A large bone plate had been removed, leaving a sizeable
depression, but he had a pleasant face and manner, smiling symmetrically
and extending his left hand to shake my hand when we were introduced.
The left hand quickly and appropriately handled a variety of objects while
he looked at them. He was quite adept at handling both brakes and both
pedals of his wheel ehair with his left hand and left foot. The ability to
manipulate objects quickly and appropriately in the left hand was also
present with his eyes closed. In contrast, when verbally requested to hold
up a particular finger of the left hand, he could not do this at all. However,
he could quickly imitate gestures with various finger positions.
He could wiggle his right toes a little when verbally requested. The right
hand had a mild spasticity in flexion; and he could increase, on verbal
request, the flexor tone of his fingers . He could not extend his right
fingers and could not flex or extend his right thumb. The left plantar
reflex was flexor, the right distinctly extensor.
His speech consisted almost entirely of ²Yes, but² with an occasional
³but-uh, no² (usually at an appropriate time) and from time to time he
would say ³God damn it². On repeated testing, he did not name any object
shown to him or put into his left hand. However, when he was shown a pen
and was simultaneously told by Dr. Smith, ³say pen², he said, ³Well, uhPEN
² quite clearly. On one occasion when asked what he wanted to do, he
said, ³Uh, duh, uh HOME!². He was then asked, ³Do you mean you want to go
home?², and he replied, ³Yes, by God!². When shown a picture of his
granddaughter, he smiled; and when asked ³Is this a boy or a girl?², he
said, ³girl².
His disability in speaking was in marked contrast to his good
comprehension of speech. Also, he frequently picked the correct picture
(of four offered) when shown a printed word. Care was needed to be
certain of his ability to read, since he was constantly watching the faces
of the people who were around him; when given a more difficult word, he
would make slight motions at several pictures (while watching his
examiners) before committing himself.
Two observations are of particular interest. First, he correctly chose the
pictures corresponding with a variety of printed nouns; but in contrast, he
missed a number of verbs. Second, he was unable to identify correctly a
picture corresponding to nouns in cursive script. This marked distinction
between words which were printed and words in cursive writing was
repeatedly confirmed.
Description of fig. 10 (11 months post-op). The patient was not able to write with his left hand although holding the pen appropriately. When asked to write ³something², he made a capital ³E² and a small squiggle. He was then asked to write the word ³cat² and he wrote a capital ³C², ³o², and ³x². He was asked if this was an attempt to write his name and he said ³God damn it². He was then urged to write his name, and he very laboriously printed the five letters of his last name. In contrast with this minimal production with a great deal of effort, he was able to copy a variety of geometric figures with ease. For example, he completed the Greek cross with a single, clockwise stroke (upper right). His copy of the cube was somewhat more deliberate and quite precise. Judging from his facial expression, he was very pleased that he was able to do this so easily.
Figure 10
FIG 10.
6a. Discussion on Agraphia
The patient ³Tan² reported by Broca in 1861 (35) was unable to speak at a
time when he possessed good understanding and could vocalize.
Neurologists, their attention aroused, soon found many similar eases; and
they soon adopted the term ³aphasia²suggested in 1864 by Trousseau (36).
Aphasia was recognized as usually indicative of left hemisphere injury
because of postmortem findings of lesions in the left hemisphere, as well
as its common association with right hemiplegia but not with left
hemiplegia; the pioneering studies of Dax on this question have been
described by Critchley (37) and by Joynt and Benton (38).
Trousseau pointed out that aphasia could occur without paralysis, and that
it was typically accompanied by a defect in writing even in those patients
without paralysis. Then in 1867, Ogle (39) reported an aphasic (his Case
V) who could write, and another patient (his Case III) who spoke well but
had
an inability to write which Ogle called ³agraphia². [{According to
Leischner in the Dutch Handbook, vol.4p141-180, the term ³agraphia² was
introduced by Benedikt in 1865 }]. Hecaen, Angelergues and Douzenis (40)
have reviewed the subsequent literature on agraphia, which may be briefly
summarized as follows:
Agraphia is found in association with aphasia both expressive and receptive, with apraxia and with alexia; these combinations usually result from lesions in frontal, temporal, parietal or occipital areas respectively. Some authors (Exner, Henschen, Herrmann and Potzl. ,Nielsen, etc.) argued the existence of a discrete writing center in the second frontal convolution. Agraphia was then explained as the result of injury to this center or to the afferent supply to this center from various other cortical areas. However, other neurologists (such .as Marie, Von Monakow, etc.) were more holistically inclined and ( among other reasons) considered writing too recent an acquisition in human history to have established its own ³center² in the brain.
At one time, even so holistic a thinker as Goldstein (41) could believe in a discrete writing center. As time passed and more data accumulated, it became progressively more apparent that there is no such thing as a special writing center, as was admitted by even so strong a localizer as Bing (42). We might paraphrase Jackson¹s well known remark on speech (43), ³to localize a lesion which disturbs writing is one thing, to localize writing is quite another.². In fact, even localizing the lesion can be a dubious enterprise, for as that extreme topist, J. M. Nielsen (43a) eventually concluded, ³. . . the subject of agraphia is the ultimate in difficulty of cerebral localization on the basis of it alone.² Summarizing further from Hecaen et al (40):
Dejerine early emphasized that spontaneous writing and ability to copy were often dissociated. This and similar phenomena led to a descriptive segregation of various types of agraphia. For example, Wernicke separated literal agraphia from verbal agraphia; Pick distinguished a loss of graphic imagery, of optic imagery and of motor imagery; Foix distinguished total agraphia from agraphia with conservation of copying; Kleist distinguished an ideokinetic from a ³constructive² form; Lehman-Facius distinguished apraxic, amesic and constructive forms; and Leischner distinguished an aphasic from an opticospatial form.
The distinctions made by these writers are largely attributable to the
dissociation of copying from spontaneous writing. For example, Pitres
(44) pointed out that the ³pure case² of agraphia reported by Charcot
eould easily ³copy a model²; and Pitres presented a case of his own: A
thirty-one-year-old man who could not write individual words (for
example, Bordeaux) but who could copy these words if they were printed
(but apparently not if they were written in cursive script). This patient of
Pitres could also trace ³geometric ³ figures or the profile of a face.
Ogle¹s original agraphic patient could copy geometric figures. Herrmann
and Potzl (45, I am indebted to Dr. H. Haeusler for translation of this
monograph) discuss a case where agraphia was so pronounced that the
patient could not copy individual written letters but could still copy
simple drawings. Nielsen (46) and Goldstein (47) cited similar cases. Both
Brown-Sequard (48) and Jackson (49) went so far as to consider loss of
writing with retention of copying a typical finding in ³speechless
persons², And Gowers (50) wrote:
³the impairment of writing in motor aphasia is a matter of daily clinical
observation ³
and in such cases ³spontaneous writing and writing from dictation are alike abolished... but the patient is able to copy. . . ³..
The separation of agraphia into two main types (by Wernicke, Foix, Kleist,
Leischner, ete.) fits recent views on segregation of verbal and spatial
specializations to opposite sides of the brain. Indeed, Hecaen, et al (40),
in their study of agraphia deliberately excluded patients with right
hemisphere lesions, because they consider it established that such lesions
cause a deficit in utilization of space, thus producing a ³spatial
dysgraphia² which is not specifically related to language function. The
data reported here are clearly in line with a belief in the segregation of
certain functions to either hemisphere; and these findings suggest that
retention of copying by most dysgraphic persons can reasonably be
ascribed to preservation of right hemisphere function.
There have been occasional reports emphasizing a loss of the ability to
draw while retaining writing as well as speech and reading. Herrmann and
Potzl (45) reported such a patient, as did Von Stauffenberg (51) and
Kennedy and Wolf (52). But tests of the ability to copy a simple drawing
are not always included in examination for agraphia. Rather, in recent
years such tests have been used in the investigation of ³constructional
apraxia,² which will be discussed further on.
One interesting sidelight of these results is their relation to what Nielsen
called, ³the dictum of Dejerine.². That is, writing one¹s own name is not a
propositional act, but is done almost automatically. We see in figures 4b,
4d, 7e, 8e and 8f that the left hand is capable of (and sometimes insists
upon) producing a signature even when it does not otherwise write
spontaneously or to dictation; it is important to recall that this does not
demonstrate an ability to ³write² in the usual sense. My failure to
understand this dictum until later was responsible for the mistake of
discarding some material from the August 31, 1965, examination of C.C.
while retaining the signature; hence Figure 5b does not really illustrate
the fact that C.C. could write well with his right hand at the time of that
examination.
The data presented here make it quite clear that left-handed dysgraphia is
a typical, though not necessarily permanent consequence of callosal
section. In all of our patients, the dysgraphia was restricted to the left
hand; even while several of them were mute, they could write legibly and
sensibly with the right hand. The dysgraphia was apparently the result of
some right hemisphere deficiency; that is, we should not consider it a
diaschistic or other defect of the ³brain as a whole².
We can be more specific as to the nature of the right hemisphere
deficiency. First of all, the left hand could draw well at a time when it
was agraphic; so it is not a question of a deficiency in motor function.
One might suppose that the agraphia resulted from an absence of engrams
for language on the right side; that is, the agraphia might be considered
simply a symptom of disconnection of the right hemisphere from the
language areas of the left as proposed by Geschwind (53). The rapid
recovery of writing in
the left hand in several cases is against this interpretation; but this can
be rebutted by ascribing the recovery to emergence of ipsilateral control.
The principal reason for not being content with disconnection alone, is
that there are language functions in the right hemisphere. For example,
although they cannot name an object placed in the left hand, most of these
patients can retrieve with the left hand from a bagful of objects
whichever object is named. That is, even when it does not use them in
speech or writing, the right hemisphere ean recognize words (10,11, 32).
The agraphia is evidently the result of a lack (or inhibition) of functioning
connections between intact gnostic and intaet effector elements of the
right hemisphere. That some active inhibitory process is involved is the
more attractive hypothesis since it suggests that we may find a specific
method to enable the right hemisphere to write (or speak) after left
hemisphere damage.* This notion implies that as a particular function
comes to be progressively more active in one hemisphere, it is
progressively more inhibited in the other; and it is conceivable that
release from the inhibitory process would uncover a capacity which has
been suppressed rather than lost.
A related phenomenon from the laboratory is illustrative of release from
inhibition. Removal of sensorimotor cortex in the cat (55) or monkey (56)
causes a loss of placing in the contralateral forelimb; later removal of the
other sensorimotor cortex restores the placing. It can be concluded from
these studies that the absence of function following the initial lesion
arose from an unbalanced tonic (ongoing) ipsilateral inhibition.
Analogously, the establishment of dominance for verbal expression in one
hemisphere may be accompanied by the development of inhibition of verbal
expression in the other (so-called minor) side. The gradual subsidence of
such tonic inhibition may be responsible for some of the recovery
following brain injuries. One can further suppose a complementary
inhibition of visuo-spatial activity in the verbalizing hemisphere. When
one hemisphere becomes dominant for both verbal and visuo-spatial
activity (as in cerebral hemiatrophy) the postulated inhibitory activities
would not develop. The tonic inhibition in the normal could be at least in
part interhemispheric, so that commissurotomy (or hemispherectomy)
would necessarily incline to some resumption of the previously
suppressed function.
7a. Discussion on Constructional Apraxia
[{since this paper was published I have been told that this term was introduced by Lhermitte and Trolles in Encephale 28:413-144,1933}]
In their concise review of apraxia in 1963, Hecaen, Ajuriaguerra and Angelergues (57) consider Steinthal to have been the first to use the word ³apractic² to refer to certain movement disorders. And they recognize the distinction made by Jackson between voluntary and automatic movements: Jackson (58) described a patient who was unable to move his tongue when requested, but used it well when eating or swallowing. Hecaen and his colleagues agree with the generally held opinion that the first thorough study was made by Liepmann (59). Also, they prefer Liepmann¹s definition: abn ³in
capacity for action though motility is unharmed, the inability to mobilize parts of the body for a definite purpose...². (We are concerned here with the central idea of ³ideokinetic apraxia², rather than the flanking concepts of ³kinetic apraxia² and ³ideational apraxia.²).
When Wilson (60) reviewed the early history of apraxia he defined it as, ³inability to perform subjectively purposive movements or movementcomplexes, with conservation of motility, of sensation, and of coordination.². Reference was subsequently made to this definition by Head (61). Denny-Brown (62) and Brain (63). But Head added, ³. . . apraxia rarely occurs alone...². Indeed, representatives of the Von Monakow school, for example Brun (64) felt that apraxia was always accompanied by at least some deficit in sensation, ideation or motor function. This difference of opinion need not concern us for several reasons. In the first place, we can hardly expect to eliminate completely any possibility of a defect in sensation or coordination. More important, as Hecaen, Ajuriaguerra, and Angelergues point out, a patient with apraxia can easily have some other defect superimposed; it would be a semantic artificiality to insist that he can then no longer have apraxia. The essential feature of apraxia is that the patient does not carry out an act at a time when he indicates in some way his comprehension of what is required and his intent to do it, whereas he can perform the required motions under other circumstances. Such a situation obtains with particular clarity in the unilateral apraxia which appears after a transection of the cerebral commissures. Cerebral commissurotomy in the right-hander is followed by a period of apraxia for the left hand whose duration differs from one patient to the next. During this period, the patient is unable to follow a verbal instruction with the left hand, such as ³Stick out your left little finger,² although he quickly follows such instructions with the right hand, and although he can do the requested act with the left hand if he is shown by demonstration what is expected of him. Similarly, although unable to perform with his left hand an abstract action such as, ³pretend you are using a pair of scissors² or ³pretend you are turning a door knob², the patient readily executes the appropriate motions if the scissors is placed in his left hand, or if he is asked to go through a door while keeping his right hand in his pocket. Although this apraxia in the left hand subsides more rapidly than the left-handed agraphia, it may be based on a similar inability of the right hemisphere to translate verbal comprehension into action. For our present purpose, it is important to note that this apraxia to verbal instruction is not present in the right hand of the patient with cerebral commissurotomy and cannot be responsible for the inability to copy geometric figures with the right hand. Furthermore, when the righthanded dyscopia is present, the right hand readily draws to verbal instructions. The right-handed dyscopia therefore can be considered an apraxia of the left hemisphere in following visuo-spatial instructions.
The concept of constructional apraxia was developed especially by Kleist,
who defined it according to Critchley (65) as, ²a disturbance which
appears in
formative activities (arranging, building, drawing) and in which the
spatial part of the task is missed, although there is no apraxia of single
movements². We have just noted that apraxia following hemispheric
separation is dependent on the side tested and on the sensory modality of
instruction. A review of previous investigations of constructional apraxia
leaves the impression that instructions have often tended to use two or
more modalities simultaneously, have not restricted input to one or the
other hemisphere, and have often permitted use of either or both hands
simultaneously. The ambiguities thus engendered make it particularly
difficult to discern the relative roles of the two hemispheres, especially
when the hemispheric damage is not precisely known. In spite of these
many variables, however, there has been accumulating in the past two
decades a body of evidence suggesting a difference in the contribution of
the two hemispheres to constructional apraxia.
In 1944, Patterson and Zangwill (66) pointed out that constructional
apraxia was known following diffuse disease, bilateral disease or disease
of the left hemisphere; it was their particular interest to emphasize the
role of the right hemisphere. Neuropsychologic studies on patients with
tumors are often contaminated by pressure and other secondary symptoms;
and patients with thrombotic lesions often have widespread vascular
changes. Particular interest attaches therefore to studies of patients
whose condition has stabilized after known surgical intervention; such a
study by Hecaen et al in 1956 (67) confirmed a special role of the right
hemisphere. I cannot review here in detail the many subsequent studies
which have been published; but the accumulated evidence continues to
support this conclusion. The evidence was reviewed by Zangwill in 1961
(68), and again in 1964 by Piercy (69) who wrote:
³It is now clear that failure on constructional tasks under visual control
occurs more commonly and takes a more severe form with right than with
left hemisphere lesions. ..².
When Piercy, Hecaen and Ajuriaguerra (69a) reviewed three thousand neurological cases, they found 67 with constructional apraxia; they found constructional apraxia twice as common with right-sided lesions. They also referred to the earlier opinions of Lange, Dide, and Scheller and Seidmann that the right hemisphere plays a special role in constructional apraxia. Their paper is notable further for emphasizing the fact that provision of a model improves the performance of the patients with left hemisphere lesions but not those with right hemisphere lesions. This resembles the findings following cerebral commissurotomy; and it seems most easily explained by the ability of the right hemisphere to copy whereas the left hemisphere cannot. These authors suggest that the constructional apraxia from right hemisphere lesions is related to a defect in visuospatial conception, whereas the constructional apraxia with left hemisphere lesions is usually indicative of a more general motor apraxia. (An inability to copy which is apparently of this type appears briefly in the left hand following cerebral commissurotomy, as shown in Figure 8-A of the paper, and Figure 1 of Bogen and Gazzaniga (7).) The view that constructional apraxia from a right hemisphere lesion is related to a visuo-spatial agnosia was advanced earlier by Ettlinger, Warrington and Zangwill (70), and by McFie and Zangwill (71) and more recently by Alajouanine and Lhermitte (72). When Warrington, James and Kinsbourne (73) specifically investigated drawing disability in relation to the laterality of lesion, they found that: ³A defect in incorporating spatial information into the drawing performance characterizes the right-sided (that is, the right hemisphere) type of impairment.².
The data from patients with cerebral commissurotomy enables us to distinguish clearly the apraxia for verbal command from apraxia in following visuo-spatial instructions. This distinction is made possible by the considerable extent to which the requisite capacities are lateralized to their respective hemispheres.
7. The Other Side of The Brain -A Personal View
The phenomenon of D-D raised for me a question which could easily have
been raised a priori by a sufficiently open mind: What is the right
hemisphere for, in the human scheme of things?
One of the most obvious facts about the cerebrum is that it is double. One
hemisphere is structurally the gross mirror image of the other*; and the
metabolic rate of one is essentially the same as the other. That is, the
other side is not only structurally the same, but it is working just as hard.
I submit that the informational capacity of the one is just as great as the
other; or, put differently, the other side is not only working just as hard,
but also just as intricately.
In the human, speaking, reading, and writing are largely dependent on one
side. While all this is happening on one side of the brain, what is the other
side doing? I believe that it is doing just as much and just as important
work. We do not yet understand how the one hemisphere produces language;
but of the other hemisphere we do not even know what it is producing. It
seems to me, therefore, that in our attempts to relate mind to brain we
should remember that:
(1) The other side of the brain is as intricately active as the side which
does most of the talking.
(2) The lesser known and hence more fruitful area for investigation of
mental activity is that carried out by the other side of the brain.
Having reached this viewpoint on rational grounds, the empirical evidence to support it can be recognized in great abundance. Some more of this evidence will be discussed in Part II of this paper, together with an hypothesis based on these facts and considerations.
*Cerebral asymmetry was reviewed by von Bonin (74); an important exception was reported by Geschwind and Levitsky (75).
The complete bibliography will appear at the conclusion of this three part series. [{ remarks enclosed in both brackets and curly brackets were added in 1999 when the OCR version was prepared for this web page.}].