Nrur,,pcycholog,u.
Vol
21,
Prmted in Great Bnta~n.

No

6. pp.

799-809,

19R9.
ii

CNX-3932/89
S3.00+0.00
1989 Pergamon Press plc

HEMISPHERIC
ASYMMETRY
OF PROCESSING
TEMPORAL
ASPECTS OF REPETITIVE
MOVEMENT IN TWO PATIENTS
WITH INFARCTION
INVOLVING THE CORPUS CALLOSUM*
ASAKO KASHIWAGI,~~ TOSHIHIRO KASHIWAGI,~ TAKASHI NISHIKAWA $ and
JUN-ICHIRO OKUDA 1)
+Department
of Rehabilitation,
Kyoritsu Rehabilitation
Hospital, Japan; IDepartment
Kyowakai Hospital, Japan; $Department
of Neuropsychiatry,
Hoshigaoka
Kosei-Nenkin
llFaculty of Health and Sport Sciences, Osaka University, Japan
(Receitled 21 June 1988; accepted 29 November

of Rehabilitation,
Hospital, Japan;

and

1988)

Abstract-Two
right-handed
patients with infarction involving the forebrain commissural
fibres
produced irregular but rapid repetitive movements with their left hands while producing normal
movements with their right hands as well as having normal oral expression. The abnormality
was
more conspicuous when producing slow tapping patterns. When required to reproduce rapid tapping
patterns of around 5 beats/set, one of the patients produced a comparatively
regular tapping pattern.
Thus, we believe that both hemispheres are equipped with the faculty to produce rapid repetitive
patterns and that only the left hemisphere is responsible for the temporal processes involved in
producing required repetitive patterns.

INTRODUCTION
PROCESSINGTEMPORALaspects of movement is one of the fundamental
faculties underlying
human behaviours such as language performance. This faculty is often designated as rhythm
formation and has been discussed in terms of the rate and regularity of repetitive movements
in experimental
studies. WYKE [18, 191 found that left-brain damage reduced the rate at
which repetitive movements were performed in both the ipsilateral and contralateral
hands,
whereas right-brain
damage resulted in a slowing of movements only for the contralateral
hand. CARMON [l] studied sequenced motor performance in patients with unilateral cerebral
lesions, and found that left-sided lesions caused more noticeable deficiency at a fast pace than
right-sided lesions and a reverse trend occurred at a slow pace. KIMURA and ARCHIBALD [S]
found that lesions of the left hemisphere
impaired the performance
of complex motor
sequences in either hand. Recently, MCMANUS et al. [9] inferred from the data of normal
subjects that the right-hand superiority in inter-tap intervals was a consequence of cerebral
dominance in control mechanisms.
The literature seems to imply left-hemisphere
dominance in the performance of repetitive
movements. If this implication is correct, patients with corpus callosum lesions would have
dissociation
between hands. In this paper we describe the performances
of repetitive
movement in two patients with callosal disconnection
syndrome due to cerebral infarction.
*This paper was read at the 10th meeting of the Neuropsychology
VCorrespondence
should be addressed
to: Asako Kashiwagi.
Shioyama 281, Kawanishi 66641, Japan.

Association of Japan,
Kyoritsu
Rehabilitation

Himeji, 1986.
Hospital,
Hirano-

800

A. KASHIWAGI rt ~1

CASE REPORTS
Cusr 1
Y.Y. wasa 56-yr-old right-handed
public official with 16 yrofeducation.
Hedevelopcd
sudden paresisofthe
right
lower limb in December 1983 and was admitted to a local hospital. He was diagnosed as having cerebral thrombosis.
but no pathological
lesion was recognized with a CT scan. He began work again in September 1984 hut needed
assistance in both commutation
and office work. On 14 July 1985, he was found unconscious
in bed by a family
member and brought to another local hospital. His CT scan disclosed a large low density area extending from the
temporal to occipital lobes in the left hemisphere. He was transferred to Kyoritsu Rehabilitation
Hospital for further
investigation
and rehabilitation
on 31 October 1985.
Y.Y. was alert and cooperative
for examinations.
He was disoriented in time and space due to amnesia but his
general intelligence was not grossly impaired. Right homonymous
hemianopia
was disclosed in the confrontation
method. The other cranial nerves were normal. Tendon reflexes of both lower limbs were moderately exaggerated
but there was no right--left difference. Pathological
reflexes and ankle clonus were negative. Muscle tone was
normal. He was not ataxic. Although having neither gross paresis nor definite sensory loss, he demonstrated
a small
step arterosclerotic
gait (dPmar&
ti petit pus) with freezing phenomena
in the right leg and desynchronization
in
manual pronationsupination
diadochokinesis
where the right limb produced steady movements while the left limb
produced rapid and unsteady movements. His grasping reflex was negative.
His CT and MRI scans (Fig. I) showed lesions situated in the posterior half of the genu and the whole truncus of
the corpus callosum as well as in the posterosuperior
portion of the left medial frontal lobe. and in the left medial
temporo-occipital
lobes. Spots of low density were also found in the bilateral basal ganglia.
Neuropsychologically,
Y.Y. showed ideomotor apraxia. agraphia and tactile anomia only with the left hand.
Diagonistic apraxia was also observed. He exhibited neither tactile extinction nor auditory extinction to nonverbal
or verbal stimuli in the sense of TANALE er a/. 1161 when manual responses were asked. However. when verbal
responses were required, auditory or tactile stimuli to the left ear or hand were almost completely extinguished
in
bilateral simultaneous
stimulation
tests. The details of these phenomena,
designated as apparent extinction, have
been reported by NISHIKAWA et al. 1141. Visuo-motor
ataxia (atauie nprique) was positive with the right hand in the
left visual hemifield. The right hand demonstrated
marked left unilateral spatial neglect’in such tasks as line
cancellation,
copying line drawings.
line bisection and matching identical figures while the left hand did not
demonstrate
any abnormality
131. These findings led us to believe that he had callosal disconnection
syndrome. Hc
was not aphasic. According to the WAIS, his verbal IQ was 63 and performance
IQ was off the scale with either
hand.

K.A. was a 68-yr-old right-handed
retired local official who had had I6 yr ofeducation.
He suddenly developed
left hemiparesis in Decemer 1975 and he was diagnosed as having cerebral embolism at a local hospital. He resumed
the ability to walk 6 months following the onset. In October 1981, he developed paresisin his right lower limb for
IO min. Two weeks later he developed a weakness in both lower limbs which lasted for several minutes. On 2
November 1981, he developed left hemiparesis and was unable to walk. His CT scan at this time revealed an infarct
in the right occipital lobe. One month later he could walk again with assistance. On 17 December 1985, he was
admitted to Kyoritsu Rehabilitation
Hospital to receive rehabilitation
treatment.
K.A. was fully alert, well oriented in time and space, and cooperative
for examinations.
Left homonymous
hemianopia
was demonstrated
in the confrontation
method. His ocular movement was normal. however he had
some difficulty in fixing his gaze upon a target in the right visual field and poor optokinetic nystagmus in pursuing a
target moving from the right to the left. K.A. had slight sensation loss and slight weakness on the left side of his face.
There was no gross weakness in the four limbs although
Barre’s sign was positive in the left upper limb. His
diadochokinetic
performance
was good with the right hand but was poor with the left hand. His grasp rellex was
prominent in the left hand. An instinctive grasping response was also present in the same hand. There were no
tremors in either hand. Tendon reflexes were decreased in both upper limbs. There were right unilateral Babinski
and Chaddock reflexes. His gait was slow and slightly unsteady. Both tactile senses and proprioception
were slightly
defective on the left side. His performance
in a two-point discrimination
test was almost normal.
The CT scan (Fig. 2) showed two major low density areas. One was in the posteromedial
portion of the right
hemisphere, extending from the temporal lobe to the occipital lobe. This lesion included a posterior portion of the
thalamus, the pulvinar and the commisural fibres running through the splenium of the corpus callosum. These areas
roughly correspond to the territory of the right posterior cerebral artery. The other was located in the medial portion
of the right hemisphere, covering the fibres through the genu and the truncus of the corpus callosum, and a medial
portion of the superior frontal gyrus. These areas roughly correspond
to the territories of the pericallosal
and
frontpolar arteries branching from the right anterior cerebral artery.
Ncuropsychologically,
K.A. showed various disconnection
symptoms such as ideomotor apraxia, agraphia and
tactile anomia confined to his left hand. In addition, his left hand showed “crossed avoiding reaction” in the sense of
LECHEVALIEKrr ul. 161. a stereotyped inhibitory response of the limbs in reaching movements and precision grip
posture when guided by a sensory stimulus in the hemifield contralateral
to the limbs. K.A. could not reach for and

PKCK’ESSING

FIG. I. Y.Y.‘s CT scans

TEMPORAL

ASPECTS

OF REPETITIVE

MOVEMENT

(3 Dec. 1985) and his median sagittal MRI (20 Feb. 1986): IR method
(TR = 2100 msec, TI = 600 msec).

802

A. KASHIWAGI et al.

FIG. 2. K.A:s

CT scans (13 June

1986).

PROCESSING

TEMPORAL

ASPECTS

OF REPETITIVE

MOVEMENT

803

grasp a target object located in the right visual hemifield with his left hand while he could perform the same task with
little effort with his right hand [4]. K.A. would not try to use the left hand in daily life although he occasionally used
it automatically,
e.g. the left hand reached for the desk without effort for supporting his body when standing up.
With his right hand K.A. exhibited left unilateral neglect. His left hand could not be tested. Performance
on
constructional
tasks was also impaired with the right hand. The left hand could neither draw any recognizable figure
nor manipulate cubes. According to the WAIS, his verbal IQ was 118 and performance
IQ was 60.

OBSERVATIONS

IN REPETITIVE

MOVEMENT

The following tests were carried out from January to August in 1986 for Y.Y. and from
March to June for K.A. Almost the same results were obtained from the re-tests carried out
for Y.Y. in April 1987 which we will not describe here.
1. Up-and-down

movement

and pronation-supination

with upper limbs

For both tasks, Y.Y. was seated on a chair with both upper limbs extended forward: he was
asked to move them up and down reciprocally or pronate and supinate them simultaneously.
The speed of motion was his choice. K.A. refused to perform these tasks.
Y.Y. performed the up-and-down
movement 6 times with his right limb and 12 times with
his left in 5 sec. In pronation-supination
he performed the motion 4 times and 11 times,
respectively. The right limb produced steady movements while the left limb produced rapid
and unsteady movements
where durations
of both action and pauses were irregularly
floating. Thus, both limbs did not synchronize.
2. Rhythm

production

in time to singing

The subjects were required to produce rhythm with a unilateral upper limb in time to
singing familiar songs. In the case of Y .Y., tapping was carried out by means of beating on the
surface of a desk with his palm. The whole upper limb was extended slightly and held forward
above the desk as a home position. The order of hand use was random. The responses were
recorded with a VTR and then the sound signals were processed with a pen recorder (Nihon
Kouden ECG 5303, filter band-pass: 0.05-75 Hz, paper speed: 2.5 cmjsec). The waveforms
of the beats and voice were identified by the authors while watching the VTR monitor.
Conversely in the case of K.A., the sound produced by tapping on the desk with his left
upper limb was too low to be processed using the same procedure as Y.Y.‘s, he was therefore
asked to click a pair of castanets with his first three fingers. The order of the hands used was
random. His responses were also recorded with a VTR. Since voice and clicks ofcastanets are
different in frequency spectra, the following two electronic circuits were employed to process
the audio signals from the two sound sources. One was for the clicks of the castanets,
consisting of a 2.G5.0 kHz band pass filter, a rectifier and a 40 Hz low pass filter. The other
circuit was for voice, comprising a 0.5 kHz low pass filter, a rectifier and a 30 Hz low pass
filter. Each of the output signals, representing
envelope waveforms, was fed into the dualchannel pen recorder.
As for manual tapping and electronic signal processing, exactly the same procedures as
above were repeatedly employed in the tests hereafter.
Samples of the responses in this test are illustrated in Fig. 3. While both Y.Y. and K.A.
could sing songs and produce rhythm with the right limb in time to the singing in normal
manners, the left limb beat an unsteady rhythm which was totally out of time to singing. The
tempo of the left limb was by and large faster than that of the right. Furthermore,
it was not
rare that their left limbs stopped and began beating erratically or even remained motionless

no4

A. KASHIWAGI

c’f ul.

while singing. On several occasions, the two patients could not stop beating their hands after
singing or began beating abruptly some time after singing. It seemed that they lost voluntary
control. Y.Y. said, “I cannot sing well if I tried to tap in time to singing.” In case of bimanual,
simultaneous
rhythm
production,
the left limb showed
similar
abnormalities
and
consequently
both limbs did not synchronize.

I

1

b

I

(

ui

hs.

Lt. Hand

i 1
A

117~1(J311J2J711

y

IJ?J

m11-

JJ

~

:

~

,,

1-/J--7

-II.

‘I

I

FIG. 3. Production
of rhythm by an upper limb in time to singing Kuroduhu.shi (Y.Y.) and SW~.tru
(K.A.), Japanese familiar songs. Each patient sang in appropriate
rhythm as indicated by the musical
notes imposed.

3. Reproduction

of slow repetitive

patterns

(1) Reproduction
in response to auditory stimulation. While being blind-folded,
the subjects
were asked to reproduce several repetitive patterns in the same manner as in Section 2,
tapping with an upper limb on the desk (Y.Y.) or clicking the castanets (K.A.), immediately
after listening to an 8 set model pattern demonstrated
by an examiner. They were instructed
to keep responding
until the examiner gave a sign to stop: the duration of a response was
approximately
8 sec. The patterns that were presented were as follows: Pattern (a) OXXX,
(b) OXOX, (c) -.__
OOXX and (d) 000X
(“0” and “X” represent a beat and a pause,
respectively,
and the length of the underline
represents
1 set). These patterns
were
successively presented one by one in random order for the following five reproduction
modes, i.e. oral expression, right unimanual.
left unimanual,
simultaneous
bimanual and
reciprocal bimanual actions. These modes were also presented in random order. Pattern (d)
was excluded in reciprocal bimanual actions. This mode was only conducted for Y.Y. In the
figures, small black circles are inserted along the graphs of the simultaneous
bimanual and
bimanual reciprocal tasks, indicating beats of the right or left limb (Figs 4, 5 and 6).
As a whole the right-hand performance was good in these tasks. As illustrated in Figs 4 and
5, each patient exhibited no deficit in right unimanual
actions. The right-hand
movement
occasionally
became uncontrolled
in the case of simultaneous
and reciprocal bimanual
actions. Much attention to their left limb might disturb the movement of their right. For the
one-beat-per-second
pattern reproduction,
intervoice intervals were prolonged in Y.Y. and
varied in K.A. (Fig. 4). However, for more rapid patterns such as three beats per second, the

PROCESSING

TEMPORAL

ASPECTS

OF REPETITIVE

805

MOVEMENT

Lt. Pami
Rt..

Eiund.
Sim,tm_

Lt.

Biumul.
Simdtamur

r

.r i.

l:I

I
.I

‘.

.

r.

.

t

/

; .r 8. . r .

I

.#r .

1’1,;

.r.

0;

. .

1.

.

.I

t,.

Fit.
j i
.

~ :
h
.

/.’

*
.

6.

h

FIG. 4. Reproduction
of repetitive patterns: one beat per second. Note that the equipment used for
processing the recorded sound of beats into graphic displays were different for Y.Y. and K.A. See the
text.

intervoice intervals were less irregular. In contrast, the left limb showed the following
abnormalities.
The reproduced patterns were rapid and unsteady and the most rapid and
most often components were 4-5 Hz. These phenomena were observed in all the modes of the
left limb movement, i.e. unimanual actions, simultaneous
bimanual and reciprocal bimanual
actions, regardless of the repetitive patterns. Abnormalities
of the left hand inevitably led to
desynchronization
with the right. Each of the patients
grew some impatience
and
occasionally
said that the left hand moved regardless of their intention.
(2) Reproduction in response to tactile stimulation. With his eyes closed and sitting face to
face to the examiner, Y.Y. was required to reproduce the repetitive patterns as in Section (l),
immediately after the examiner had demonstrated
the model patterns by means of tapping on
the dorsal surface of Y.Y.‘s hand somewhere between the second and third metacarpi with
her index finger. The remainder of the procedures were the same as in Section (1). K.A. was
not tested.
The same results as in Section (1) were obtained: the left hand showed irregular and rapid
movements, while the right hand showed normal movements.
(3) Reproduction
in response to visual stimulation. The examiner
confronting
Y.Y.
demonstrated
model patterns by moving the extended upper limb in Y.Y.‘s left hemispace.
The remainder of the procedures such as repetitive patterns and manner of reproduction
were the same as in Section (1). K.A. was not tested.
The same tendencies as in Sections (1) and (2) were again observed in the rapidity and
regularity of the movement for both hands.

A. KASHIWAGI rt ul.

806

PA. nmd

;

Lt. tlmd

xi

nt.

Biunul.
-Siultrmws

Lt.

.

, ljl,
.

.

FIG. 5. Reproduction

i);
.

.

i L h~~ -”~/
Uh
.

.

.

.

.

.

~..

.hl

1

h

:

I

A_~_J.
hf!-L.._
.

.

*

.

of repetitive patterns: three beats plus one pause per second

1 SLmnd

m
u&t Prcsmtcd
-At. nmd
Lt. Hmd

FIG. 6. Reproduction

4. Reproduction

ofrepetitive

of rupid rrpetitiw

patterns: five beats per second. K.A. was not examined in this task.

putterns

While blind-folded, Y.Y. was required to reproduce a 4-, 5- and 6-beat-per-second
pattern
by means of tapping on the desk. A model was auditorily presented by the examiner for 8 sec.
Each pattern was performed once in this order. K.A. did not perform this task because of his
discharge from the hospital.
Samples of his responses to the 5-beats-per-second
pattern are illustrated in Fig. 6. His left
hand tapped for 445 beats and was still irregular if compared with the right hand. It was not
synchronous
with the right hand in bimanual
tapping.
It seemed, however, that the
irregularity was the least conspicuous of all the reproduction
tasks. The left hand would tend

PROCESSING

TEMPORAL

ASPECTS

OF REPETITIVE

to beat faster than the right. As for the other patterns
the same.
5. The auditory

discrimination

test of repetitive

MOVEMENT

in this task, the overall tendencies

807

were

patterns

The subjects were asked to discriminate
20 pairs of the following four patterns presented
monoaurally.
The patterns were: (a) OXXXOXXX,
(b) OXOXOXOX,
(c) OXOXXXXX
and (d) OXOXOXXX
(here the length of the underline represents 2 set). Each pattern
consisted of an intermittent
pure tone (1000 Hz, duration
of the tone burst: 250 msec,
duration
of the pause: 250 msec). Half of the pairs were “the same” and the other half
“different”. They were pseudorandomized.
The subjects' judgement as to whether the pairs
were the same or different was expressed by either raising an ipsilateral hand or not raising it.
The right and left ears were tested monoaurally
at 60 dB HL. The contralateral
ear was
masked with 40 dB HL white noise. The same test was repeated for each patient 2 days later
and the correct scores of the two sessions were individually
totalized.
The results were as follows. Y.Y. scored 100% for the first session and 90% for the second
session in right-side stimulation
and response, 95% and 100% in left-side stimulation
and
response. K.A. scored 90% and 90% in the right-side tasks and 95% and 90% in the left-side
tasks. We concluded that both Y.Y. and K.A. did not show apparent deficiencies in auditory
discrimination
of repetitive patterns in our experimental
conditions.

DISCUSSION
Both Y.Y. and K.A. had difficulties in forming repetitive patterns if they used the left upper
limb. They tended to respond with rapid, unsteady and awkward repetitive movements for
any pattern, irrespective of stimulus modalities. They showed a departure from the models in
timing and numbers of beats. The left hand was seemingly out of voluntary
control in
processing
temporal
aspects of required repetitive movements.
This tendency
became
conspicuous
when the patients were asked to perform slow repetitive movements.
In
contrast, it was confirmed that Y.Y. was consistently able to perform a repetitive movement
at about 5 Hz. Since our patients easily performed such manual actions as tapping on a desk
or clicking castanets with the left upper limb, we considered this phenomenon
to be a
disorder of processing temporal aspects of repetitive movement, i.e. a disorder of rhythm
formation in a more general sense.
Clinically, Y.Y. did not have paresis, ataxia or sensory loss in the left upper limb. K.A. did
not manifest any gross muscular weakness in the left limb, although he showed Barre’s sign,
slight defects of tactile senses and proprioception
and grasp reflex. Since these patients
showed similar behaviours
as far as temporal
aspects of repetitive
movement
were
concerned,
this abnormality
cannot
be attributed
to elementary
motor or sensory
disturbances.
Furthermore,
neither Y.Y. nor K.A. was left-handed, although each of them
could perform rapid repetitive movements with the non-preferred
left hand. TANAKA et al.
[ 171 have referred to rapid and awkward reproduction
of tapping with the right hand which
was observed transiently
in a right-handed
patient with a lesion of the corpus callosum.
Incidentally,
their patient’s severe agraphia, his solitary unilateral disconnection
sign, was
confined to the “right” hand. Accordingly,
these authors inferred that their patient’s right
hemisphere was linguistically
dominant. This fact makes it unlikely that the abnormality
of
repetitive movement resulted from the poor dexterity of the non-preferred
hand.

808

A. KASHIWAGICTul.

Furthermore,
also irrelevant

our data confirmed that auditory discrimination
of rhythm patterns was
to the cause of the abnormalities.
NAKAMURA,
R. et ~11.[12] had patients with Parkinson’s
disease tap synchronously
to
periodic sound stimuli. The patients could tap synchronously
if the sound stimuli were at the
frequency of l-2 Hz, but when the stimuli exceeded the frequency of 2.5 Hz, they abruptly
failed to respond synchronously
to the stimuli and showed a hastened tapping of 4-7 Hr
(average of 5 Hz), irrespective of the input stimuli frequencies. They called this phenomenon
the “Hastening
Phenomenon”
(referred to as HP hereafter) and interpreted it as a release ol
the intrinsic
oscillation
system in the central nervous system. Following
this study,
NAGASAKI et ul. [lo] reported that the same phenomenon
was observed with CVA patients
and pointed out its relationship
with the lateralized dysfunction of the striatum on the basis
of CT scan analysis. These authors did not necessarily explain the left&right difference in the
occurrence of the abnormality,
but they appeared to have observed a bilateral abnormality.
From the MRI and CT scan findings, lesions in the striatum could not be denied in Y.Y.
and K.A. In addition,
our patients produced rapid beats around 4-5 Hz. However, in
comparing Nakamura’s and Nagasaki’s series with ours, we see an apparent difference: our
patients’ rapid repetitive movements appeared at such slow frequencies as 1 or 2 Hz where
the 146 patients with Parkinson’s disease and the 191 CVA patients did not demonstrate
any
HP. One of the present authors observed another callosal patient without a lesion in the
basal ganglia, the site of the lesion being confirmed by medical records and MRI scans, who
transiently produced rapid repetitive movements with his left hand 1131. Furthermore,
the
patient of TANAKA et (11. [17], cited above, showed no evidence of damage to the basal
ganglias. We believe that the phenomenon
observed in Y.Y. and K.A. is most likely different
from the HP.
In keeping with this discussion, we presumed that our patients’ abnormality
in temporal
aspects of repetitive movement was most likely caused by pathologies of the corpus callosum.
This inference is partly supported
by NAKAMURA, H. et ul. [l l] who pointed out the
functional
significance
of the corpus callosum
for rhythmic
capabilities.
Thus, we
summarized
the pathological
mechanisms
of what we observed, as the following: both
hemispheres are equipped with a faculty to produce rapid repetitive patterns on the basis of
the organic intrinsic oscillation system [2, lo], whereas only the left hemisphere commits
deeply in temporal processes to attain required repetitive patterns. Our view is compatible
with the studies on biaural audition of normal subjects [7, 151 and the intrahemispheric
lesion study on a right-handed
professional
musician with a left posterior parietal lesion
exhibiting disturbances
in rhythm recognition and formation [S], as well as with the studies
cited in the Introduction.
The abnormality
of the left limb should arise in temporal aspects of
repetitive movement when the right hemisphere is released from the control of the dominant
left hemisphere due to lesions of the corpus callosum. On the other hand, it becomes obscure
when a rapid repetitive movement of around 5 Hz is required. We speculate that the right
hemisphere is most likely resonant with rapid patterns neighbouring
this tempo. However,
the abnormality
is salient when a relatively slow repetitive movement is required, because the
non-dominant
right hemisphere is not qualified to voluntarily
control tempi of repetitive
movements.
AcknowledUemmts-We wsould like to express OUTthanks to Drs Kenzo Kiso (Kyowakai
Hospital),
Osarnu
Kunitomi (Yuaikai Hospital), Tsuyoshi Nishimura, Junzo Shiraishi, Hirotaka Tanabe (Osaka University). Atsushl
Yamadori (Hyogo Brain and Heart Centre at Himeji), Morio Kono (Kobe City University of Foreign Studies) for
their support and invaluable suggestions and to Ms Hisako Sakaegi for her cooperation
In the experiments.

PROCESSINGTEMFORALASPECTSOF REPETITIVEMOVEMENT

809

REFERENCES
1. CAKMON, A. Disturbances
of tactile sensitivity in patients with unilateral cerebral lesions. Cortex 7,83%97,1971.
2. ITOH, M. Noh no Sekkeizu (in Japanese). Chuoh Kouron-sha, Tokyo, 1980.
3. KASHIWAGI, A., KASHIWAGI, T., NISHIKAWA, T., TANABE, H. and OKUDA, J. Left unilateral neglect confined to
the right hand in a patient with the callosal disconnection
syndrome. Paper read at the 1 Ith meeting of the
Neuropsychology
Association of Japan, Tokyo, 1987.
4. KASHIWAGI, T., KASHIWAGI, A., SAKAEGI, H., KOBAYASHI, M., NISHIKAWA, T., OKUDA, J., SHIRAISHI, J. and
NISHIMURA, T. A patient with a crossed avoiding reaction (in Japanese). Shitsugosho Kenkyu 7, 78, 1987.
5. KIMURA, D. and ARCHIBALD, Y. Motor functions of the left hemisphere. Brain 97,337-350,
1974.
6. LECHEVALIER, B., ANDERSSON, J. C. and MORIN, P. Hemispheric
disconnection
syndrome with a “crossed
avoiding” reaction in a case of Marchiafava-Bignami
disese. J. Neural. Neurosurg. Psych&. 40,483497,1977.
7. LEEK, M. R. and BRANDT, J. F. Lateralization
of rapid auditory sequences. Neuropsychologia
21,67-77,
1983.
8. MAVLOV, L. Amusia due to rhythm agnosia in a musician with the left hemisphere damage: a non-auditory
supramodal
defect. Cortex 16, 331-338, 1980.
9. MCMANUS, 1. C., KEMP, R. 1. and GRANT, J. Differences between fingers and hands in tapping ability:
dissociation
between speed and regularity. Cortex 22, 461473,
1986.
10. NAGASAKI, H., KOSAKA, K. and NAKAMURA, R. Disturbances
of rhythm formation in patients with hemispheric
lesion. Tohoku J. Exp. Med. 135, 231-234, 1981.
11. NAKAMURA, H., NAGAFUCHI, M., NAKAMURA, S. and KOGURE, K. Functional
significance of the corpus
callosum based on the analysis of rhythmic capabilities in the split-brain patients. Tohoku J. Exp. Med. 142,
363-379. 1984.
12. NAKAMURA, R., NAGASAKI, H. and NARABAYASHI, H. Disturbances
of rhythm formation
in patients with
Parkinson’s disease: Part I. Characteristics
of tapping response to the periodic signals. Percep. Motor Skills 46,
63-75, 1978.
13. NISHIKAWA. T., TABUSHI, K., OHNO, K., KASHIWAGI, T., OKUDA, J., NISHIMURA, T., TANABE, H. and SHIRAISHI,
J. A patient with infarction involving the anterior corpus callosal--callosum
apraxia (in Japanese). Shinkei
Shinriqaku 2, 79, 1986.
14. NISHIKAWA, T., TANABE, H., OKUDA, J., KASHIWAGI, T. and KASHIWAGI, A. Extinction in cases of callosal
disconnection-“apparent
extinction” and some additional
findings in dichotic listening tests (in Japanese).
Shinkei Shinriqaku 4, 33 46, 1988.
15. ROBINSON, G. M. and SOLOMON, D. J. Rhythm is processed by the speech hemisphere. J. Exp. Psychol. 102,
508-511, 1974.
16. TANABE, H., NISHIKAWA, T., OKUUA, J. and SHIRAISHI, J. Auditory extinction to nonverbal and verbal stimuli.
Acta Neural. &and. 73, 173-179, 1986.
17. TANAKA, Y., IWASA, H., KAKUDA, S. and YOSHIDA, M. A patient with right-hand
agraphia and diagonistic
apraxia (in Japanese). Shinkei Shinriqaku 3, 152, 1987.
18. WYKE, M. Effect of brain lesions on the rapidity of arm movement. Neurology 17, 1113-l120, 1967.
19. WYKE, M. The effects of brain lesions on the performance
of bilateral arm movement. Neuropsychologia
9,
33-42, 1971.