Sensory-Specific and Fractional Disorders
of Recent Memory in Man
II. Unilateral Loss of Tactile Recent Memory
Elliott D. Ross, MD
\s=b\ Three patients were found to have
unilateral tactile recent memory loss on
examination. In two patients the loss
occurred in the right hand and was
accompanied by a disorder of verbal
recent memory; in the third patient the
loss occurred in the left hand and was not
accompanied by any other disturbance in
recent memory. An acute unilateral
lesion, either structural or functional, in
the medial temporal lobe contralateral to
the tactile recent memory disturbance
was the common denominator in all three
cases. The proper methods for diagnosing a unilateral tactile disturbance of
recent memory and other forms of fractional disorders of recent memory are
discussed. Based on computerized tomography scans and behavioral and anatomical data in man and monkey, an anatomical explanation is offered to account for
the syndromes of right and left unilateral
tactile recent memory loss. The possible
existence of other forms of fractional disturbances of recent memory and the role
of the cerebral commissures in recent
memory functions are discussed.
(Arch Neurol 37:267-272, 1980)

this communication three patients

*· are described

who, on examination,

were found to have unilateral distur¬

bances in tactile recent memory. Two
patients lost tactile recent memory in
the right hand with an accompanying
disorder of verbal recent memory, and
the third patient lost tactile recent
memory function in the left hand.
These cases establish the existence of
fractional disorders of recent memory
in man and, in combination with cases
described in a previous companion
article,' help to further delineate the
anatomical basis of recent memory
functions.
REPORT OF CASES
l.-A 53-year-old, right-handed
woman was admitted to the neurology
service of Parkland Memorial Hospital on
Nov 28, 1976, because of abnormal behav¬
ior. Following head trauma in 1971, she
Case

Accepted for publication March 10, 1979.
From the Department of Neurology, Universi-

ty of Texas Health Science Center, Dallas.
Reprint requests to Department of Neurology,
University of Texas Health Science Center, 5323
Harry Hines Blvd, Dallas, TX 75235 (Dr Ross).

began to have seizures heralded by nausea
and a hot flushing sensation followed by a
loss of consciousness with generalized tonicoclonic activity and a short period of
postictal confusion. She was treated with
phenytoin sodium and phénobarbital sodi¬
um with only fair control, due to poor
compliance. Approximately four days prior
to admission, she suffered a tonicoclonic

seizure, after which she had a persistent

confusional state characterized by "staying
wan¬
up all night cleaning the house
and looking for pen¬
dering around
nies." The patient constantly talked about
seeing her husband, who was deceased for
three years, and began packing a suitcase
to "go home" even though she had been
living in her present house for three years.
She continually spat into a cup because she
thought she had "worms in her mouth,"
and appeared "lost in her own home."
On admission, the patient was slovenly
dressed and alert but confused. Physical
examination was unremarkable. Neurolog¬
ical evaluation revealed poor attention, and
she was able to repeat only four digits
forward on immediate recall testing.
Recent (verbal) memory was poor but
remote memory was relatively intact. She
was unable to do similarities or proverbs
and appeared inappropriately euphoric
with no insight into her illness. She had
intact spontaneous speech, repetition, com¬
prehension, naming, and reading. There
was no ideomotor apraxia. Right /left
orientation, finger recognition, facial rec¬
ognition of famous people and family, cal¬
culations, and dressing ability were nor¬
mal. She had difficulty in drawing a clock
but was able to draw a symmetrical flower.
Cranial nerve, motor, sensory, reflex, and
gait examinations were normal.
Within two days the patient's initial
confusional state cleared and she was left
with a profound loss of recent memory
when tested verbally. Examination on Dec
2, 1976, showed the patient to be alert,
attentive, and able to repeat six numbers
forward and four backward on immediate
recall. Similarities were performed normal¬
ly, although she was unable to interpret
proverbs. Except for recent memory (see
"Special Tests and Observations") and loss
of insight into illness, the remainder of the
neurological examination was normal.
Special Tests and Observations.—Verbal
Recent Memory.-The patient's verbal re¬
...,

...,

cent memory was severely compromised.
On repeated testing, she was unable to

retain three unrelated words after a threeminute distraction. She thought the year
was 1963 and the President was either
Kennedy or Ford. She had no idea who the
current President was, even when given
verbal choices. She thought that her hus-

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band was alive and that she was currently
living in Lufkin, Texas, where she had
lived most of her life before moving to
Dallas several years ago. She was unable to

give the correct ages of her children or
grandchildren and was unaware of the
existence of one grandchild born two years
previously. On the other hand, she gave a
correct account, according to the family, of
her personal life from the more remote
past.

Visual Recent Memory.-The patient
performed normally on testing for visual
recent memory; that is, if shown a relative¬

ly nonverbalizable object for 10 s, she was
able to choose visually the object from
among four similar objects after being
verbally distracted for three minutes. She
was tested in a similar manner with three

more

objects, with the same result. In

addition, she was able to recognize visually

her hospital physician when he was placed
in a group of four other physicians,
although she could not remember his
name.

Tactile Recent Memory.—On testing tac¬
tile recent memory, she was found to have
a profound deficit that involved only her
right hand. For instance, when she was
allowed to blindly palpate a relatively non¬
verbalizable object for 10 s with her right
hand, she was unable to tactilely choose the
object from among four others with her
right hand after a three-minute verbal
distraction time. The same task, when per¬
formed by her left hand, was done without
error (each hand was tested four times).
When this testing was repeated the follow¬
ing day, she actually remembered the four
different objects placed in her left hand
from the previous day, but still could not do
the task with her right hand. Furthermore,
the tactile memory disturbance in her right
hand could not be attributed to any ele¬
mentary sensory, perceptual, immediate
recall, or remote tactile memory loss, since
the ability to choose tactilely with her right
hand an object from among four others
immediately after that object was removed
from her right hand, the ability to match
objects between hands, and stereognosis in
her right hand were completely intact.
The patient regained full recent memory
functions by the evening of Dec 3, 1976.
She evidenced no (verbal) retrograde
amnesia, was oriented and conversant with
recent political and family events, and had
regained tactile recent memory function in
her right hand. Electroencephalography
(EEG) and brain scan were normal. A

computerized tomography (CT) scan was
not done.

The patient's confusional state and
subsequent fractional disorders of

recent memory most ljkely reflected a
postictal disturbance secondary to her
partial complex seizure disorder that
presumably involved temporal lobe

perceptual, remote tactile memory, or
immediate recall problems, since stereog¬
nosis in the left hand, the ability to match
different objects between hands, and the
ability to choose tactilely an object with his

bances would be consistent with left
medial temporal lobe dysfunction be¬
cause of the verbal and right tactile
recent memory losses. The only incon¬
sistent and puzzling finding was her
intact visual recent memory. By the
time it occurred to me that the proper
way of testing the patient's visual
recent memory was through separate
tachistoscopic presentations to her
right and left visual fields, her memo¬
ry deficits had resolved. Hence the
question of whether a visual recent
memory loss could be confined to a
hemivisual field was not answered. In
addition, the patient was not tested
for nonverbal (auditory) recent memo¬
ry with various noises and melodies
(see cases 2, 3, and 4, however).
Although anatomical correlation could
not be demonstrated on EEG or brain
scan, this case was phenomenologically important because it established for
me that fractional disturbances of
recent memory could exist in man.

ately after that object was removed from
his left hand were fully preserved.
Verbal, Nonverbal Auditory, and Visual
Recent Memories. -On testing the patient's
recent memory functions using strictly
verbal presentations (ie, a short story or

structures. The recent memory distur¬

Case 2.—A 76-year-old man was evalu¬
ated in the neurology clinic at Parkland
Memorial Hospital because of visual loss
and was discovered to have a left hemia¬
nopsia. He was admitted to the neurology
service on March 15, 1977, after a brain
scan revealed abnormal uptake in the right

occipital area.
Physical examination was normal except
for a dense left cataract. On neurological
examination the patient was alert, fully
oriented, and cooperative. Immediate re¬
call, recent memory (tested verbally),
remote memory, similarities, proverb in¬
terpretation, and judgment were intact.
He was mildly irritable and occasionally
inattentive but fully cooperative during
the examination. No aphasie disorders or
ideomotor apraxia were observed. The
patient performed well on tests of right/
left orientation, calculations, map direc¬
tions, and facial recognition, but had diffi¬
culty in copying two-dimensional figures
and drawing a clock. There was a dense left
hemianopsia with slight macular sparing in
his right eye. The left eye could only per¬
ceive light. Eye movements were full.
Motor examination was normal, with sym¬
metrical reflexes; no Babinski's signs were
present. Sensory functions were intact,
including graphesthesia, two-point dis¬
crimination, and stereognosis. Station,
gait, and coordination were normal.
Special Tests and Observations.— Tactile
Recent Memory.—Tactile recent memory
was

tested as described in case 1. This

patient demonstrated a profound unilater¬

al loss of tactile recent memory in his left
hand. With his right hand he chose the
correct object in five out of five trials, but
with his left hand he missed on all five
trials. The loss could not be attributed to

left hand from among four others immedi¬

four unrelated words), nonverbal sounds
such as noises and melodies, or visual pres¬
entations of relatively nonverbalizable line
drawings (Fig 1), he showed absolutely no
deficits, even after verbal distractions last¬
ing ten minutes. An attempt was made to
test visual recent memory in his slightly
spared left macula field through tachistoscopic presentations, but it was discovered
that he could not perceive words or objects
in that portion of his visual field. At no
time during his hospitalization did he dem¬
onstrate spatial disorientation or an inabil¬
ity to recognize his physicians by sight or
name.

CT Scan.—A CT scan with contrast was
done on March 22, 1977 (Fig 2). An infarc¬
tion involving the entire right medioventral temporal lobe, the right medial occipi¬
tal lobe, the deep right and left superior
occipital lobes, and the deep right and left
posterior parietal lobes was seen. Gyral
atrophy and mild hydrocephalus ex vacuo

present.
On April 29,1977, the patient sustained a
second stroke that left him cortically blind,
inattentive, extremely irritable, and inter¬
were

mittently confused. When testing could be
done, he appeared to have a profound
verbal recent memory disorder, but this
was difficult to quantitate because of his
confusion. A CT scan revealed a new left
posterior cerebral artery infarction involv¬
ing the left medial occipital and temporal
lobes.

This patient demonstrated a unila¬
teral loss of tactile recent memory in
his left hand, with a prominent right
medial temporal lobe infarction seen
on CT scan. Unfortunately, the pa¬
tient's left hemianopsia precluded
testing visual recent memory in his
left visual field. His intact recent
memory for nonverbal audition was
surprising because there is evidence
that appreciation of melodies in nonmusicians2 is a function of the right
hemisphere. Perhaps, if the patient
had been examined immediately after
his first ictus, he would have mani¬
fested a recent memory disturbance
for nonverbal audition.
Whether the patient's loss of left
tactile recent memory would have
eventually resolved could not be
assessed because of his second stroke.
It is possible, however, that the lesions
involving the deep parietal white mat¬
ter prevented the recovery of tactile
recent memory in the left hand by
causing a callosal disconnection to

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between the right somesthetic
associational cortex and the intact left
medial temporal lobe (see "Discus¬
sion" for clarification of this point).
Against this view is the observation
that the patient was able to transfer
tactile information between the hemi¬
spheres on tasks involving tactile
naming and object matching between
hands. Although I am not aware of
any literature that bears on the fol¬
lowing, the previous objection may
not be relevant if the transfer of
somesthetic information involved in
the naming and matching tasks were
to take a different commissural route
from the one for tactile recent memo¬
ry function.
occur

Case 3.-A retired 69-year-old righthanded man was admitted to the Dallas
Veterans Administration Hospital on July
28, 1978, following four days of nonspecific
headaches and a change in behavior. His
physical examination was normal. On ini¬
tial neurological evaluation, he had a
severe recent memory deficit (tested ver¬
bally), alexia without agraphia, partial col¬

agnosia, a right homonymous hemianop¬
sia, and poor insight into his illness.

or

Neurological examination done on the
day after admission showed him to be
alert, cooperative, and attentive. He could

repeat seven numbers forward and four

backward. There was a severe deficit of
recent memory, tested verbally, since his
knowledge of recent news events, his
orientation to time, date, and place, and his
ability to learn and retain new verbal
information after a three-minute verbal
distraction were profoundly disturbed. Re¬
mote memory, especially recall of events
concerning World War II, was perfectly
intact. Similarities, proverb interpreta¬
tions, right/left orientation, dressing, cal¬
culations, two- and three-dimensional con¬
structions, facial recognition of famous
people and attending physicians, and
knowledge of map directions and Texas
geography were without fault. He had
intact spontaneous speech, comprehension,
repetition, and writing. There was no ideomotor apraxia. Reading aloud was slow
because he tended to misread or neglect
the right half of words, but there was
excellent comprehension of the read mate¬
rial. Visual naming of objects and colors
was normal. There was mild difficulty with
tactile naming in both the right and left
hands, but he had no problems with ster¬
eognosis when a nonverbal response was
required, such as showing how an object
was used.
On cranial nerve examination, there was
a right homonymous hemianopsia without
macula sparing. The extraocular move¬
ments were full, but there was diminution
of opticokinetic nystagmus to the right.
Examination of motor and sensory func¬
tions and coordination, reflexes, and gait
were normal. Two-point discrimination,
graphesthesia, and touch localization in all
four extremities and stereognosis in the
upper extremities were intact.
Special Tests and Observations.—Tactile

Fig 2.—Computerized tomography scan (case 1). Infarction is bilateral and involves
entire right medial temporal lobe, much of right occipital lobe, small portion of left inferior
occipital lobe, and deep posterior parietal and deep superior occipital lobes bilaterally.
Arrowheads help outline lesion. Note cortical atrophy and mild hydrocephalus ex
vacuo.

Fig 1 .—Tactile test objects (left) and visual test drawings (right) used to assess
tactile and visual recent memory and immediate recall functions.
recent memory. He could also visually
recognize his ward physicians, although he

Fig 2.—Computerized tomography scan (case 1). Infarction is bilateral and involves
entire right medial temporal lobe, much of right occipital lobe, small portion of left inferior
occipital lobe, and deep posterior parietal and deep superior occipital lobes bilaterally.
Arrowheads help outline lesion. Note cortical atrophy and mild hydrocephalus ex
vacuo.

did not remember their names.
CT Scan.—A thin-section CT scan was
done on Sept 27, 1978 (Fig 3). A deep left
occipital lobe infarction that also involved
the anterior medial occipital cortex and a
small area in the anterior half and all of the
posterior half of the left medial temporal
lobe was observed.
Prior to discharge, on July 31, the patient
still manifested a dense right homonymous
hemianopsia without macular sparing but
had regained a good deal of verbal recent
memory. He was oriented to time and
place, knew some current events, and, with
cueing, could remember most of a short
story after a three-minute verbal distrac¬
tion. In addition, he no longer demon¬
strated any tactile recent memory distur¬
bance in his right hand. On reexamination
in September 1978, he still had mild prob¬
lems with verbal recent memory, but it had
clearly improved from the last examina¬
tion. The dense right homonymous hemia¬

nopsia was unchanged.
As in case 2, the hemianopic deficit

precluded testing visual recent memo¬
ry in the affected (right) field. This

time, however, the lesion involved the

Recent Memory.Vi/hen the patient's tactile
recent memory was tested in the manner
described in case 1, he demonstrated a
profound deficit confined to the right
hand. With the left hand he performed the
task without error in five trials, but with
the right hand he was correct only one out
of five times. It was also observed that he
was never sure about any of the choices he
made with his right hand, including the one
time he was correct.
This defect in tactile recent memory
could not be attributed to any perceptual,
immediate recall, or remote tactile memory
problems since stereognosis in the right
hand, the ability to correctly match differ¬
ent objects between hands, and the ability
to choose tactilely the correct object with
his right hand from among four others
immediately after that object was removed

from his right hand were fully preserved.
Nonverbal Auditory and Visual Recent
Memories.—Despite the patient's profound
loss of verbal recent memory, when he was
presented with a noise or a hummed melo¬
dy and asked to choose the correct nonver¬
bal sound from among four others after a
verbal distraction of three minutes, he
performed without error. Visual recent
memory was tested in a similar manner by
showing him a relatively nonverbalizable
line drawing for 10 s (Fig 1) and asking
him to choose the correct one from among
four others after a three-minute verbal
distraction time. He was correct in four out
of five trials and was able to narrow down
his choice confidently on the fifth trial to
two drawings, one of which was correct. He
was spatially oriented on the neurology
ward, despite his profound loss of verbal

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left hemisphere and the patient was
found to have a right tactile recent
memory loss with a profound distur¬
bance of verbal recent memory and
preservation of nonverbal auditory
recent memory. In this patient the
loss of verbal, but not nonverbal, audi¬
tory recent memory is consistent with
the current concept that appreciation
of melodies in nonmusicians seems to
be a dominant function of the right
hemisphere," while propositional lan¬
guage is a dominant function of the
left hemisphere. As might be expected
in a unilateral medial temporal lobe
infarction,'-4 the recent memory dis¬
turbances were transient and frac¬
tional.
Another important observation in

COMMENT
COMMENT

To my

knowledge, the patients

described in this report with unilater¬
al loss of tactile recent memory estab¬
lish for the first time that fractional
disorders of recent memory can exist
in man. Although these patients are
unique in the clinical literature, I do
not think they are necessarily rare.
Since infarctions involving the poste¬
rior cerebral artery comprise approxi¬
mately 3% of occlusive strokes," if one
carefully screens for tactile recent
memory in patients with posterior
cerebral artery infarctions, fractional
disorders of recent memorv should be
readily encountered.
The technique of examining pa¬
tients for tactile recent memory loss is
straightforward and has been pre¬
sented in detail in the case reports.
Fig
3.—Computerized
tomography scan (case 2). Infarction involves deep left occipital
nonverbalizable
Relatively
objects
left anterior medial occipital cortex,
lobe,
posterior half of left medial temporal lobe, and
should
be used so as to force
the
small
lobe. Arrowheads help define extent of
area in anterior left medial
temporal
lesion.
patient to make his choice based on
tactile features alone (Fig 1). If the
or even
patient can was
easilythatverbalize
this
tactile
left orientation, calculations, facial recog¬
patient
the test object,
then herecent
name
might
resolved
before
the
nition, and constructions were normal. He
ver¬
fully
memory
use verbal rather than tactile recent
evidenced no spatial disorientation on the
bal recent
disturbance
memory
select
the
to
correctlyone should object.
memory
ward and his geographic knowledge was
cleared.
not
Therefore,
a disturbance of tactile
Consequently,
intact. Language evaluation revealed only
that
assume
the
different
necessarily
recent memory could be missed. To a mild anomia. No ideomotor apraxia was
of a amultimodal
frac¬of
components
establish that
hasor aa loss
His cranial nerve, motor, sensory,
patientdisorder
tional
willbe present.
tactilerecent
it
and gait examinations were
recentmemory
must
reflex,
station,
memory,
resolve
unison.
this is the
Perhaps
shown inthat
he has
no primary normal.
(1)
reason why Paterson and Zangwill·'
Special Tests and Observations.—The pa¬
problem with tactile perception, (2) no tient's
were not able to correlate the resolu¬
tactile recent memory was tested
disturbance that could inter¬
aphasietheir
tion
through
separate trials in both the right
patients'
posttraumatic
normal
tactile
fereofwith
testing, (3)
and left hands; he made no errors on this
docu¬
recent
memory
disturbance,
immediate recall, and (4) normal tac¬ task. Visual recent
memory was tested in
mented
with
only memory.
by verbalIf means,
tile remote
one can show the
right and left visual fields via tachistheir
resolution
of
patients'
spatial
that the patient also has a retrograde toscopic presentation; again, the patient
Since
disorientation.
presented
tactile amnesia,
theI have
would demonstrated no deficits. Nonverbal audi¬
syndrome
in a Unless
article1
that
evidence
previousthere
be complete.
are excep¬ tory recent memory, tested with melodies
in patientsI with
spatial
tional disorientation
doubt and noises, was also normal.
circumstances, however,
loss proba¬
multimodal
On May 6 he underwent left anterior
memory will
that this recent
be ob¬
phenomenon
results from their visual recent
temporal lobectomy; the mass proved to be
blyserved.
a glioblastoma multiforme. Postoperative¬
it is on
of CT
great
disturbance,
memory
The lesions
encountered
scan
the patient did extremely well. When
interest
that
this
patientthe(case
3),
in cases 2 and 3 involved
and ly
rightwas
examined one week later, he had no neuro¬
whose
visual recent memory
left medial
temporal lobes, respective¬ logical deficits. The problems with imme¬
never displayed spatial disoriintact,
These
areas of the brain are tradi¬
diate recall and anomia had completely
ly.
entation,
profound
despite a with
associated
memo¬ resolved. Furthermore, he had no deficits
recentverbal
tionally
recent memory loss.
ry function,7 whereas the patients on retesting tactile, visual, verbal, and
Case 4.-A
was admit¬
40-year-old
with
isolated
loss ofmanvisual
recent nonverbal auditory, recent memories.
ted to Parkland
Memorial inHospital
on May
described
the previous
This patient is included in the case
memory
to admission he
3, 1977. Three
prior lesions
hadweeks
bilateral
that did reports to illustrate that a slowly pro¬
report1
had had several major motor seizures, fol¬
medial and
lobes. gressive lesion, in contrast to an acute
not involve
temporal
lowed
headaches
by severethe
progressive
To understand
fractional
why
A CT distur¬
confusion
with mild
lesion, involving a medial temporal
scan
anomia.
bances of recent
the lobe may not give rise to a fractional
an edematous,
demonstrated
memory
occur,cys¬
partially
and disorder of recent memory. By the
ticreasoning
lesion in put
the forth
left temporal
lobe that
by Geschwind
shifted
theconcerning
to the right.
Fusillo11
the (verbal)
midline structures
recent time this patient underwent surgical
was subsequently
He
a regimen
loss observed
placedinontheir
memory
patient removal of his tumorous left temporal
ofwith
steroids
preparation
craniotomy.
left
medial for
lobe lobe, his left hemisphere must have
a in
temporal
On neurological
two days
infarction
is of examination
relevance. They
rea¬ had time to develop sufficient access
after
was alert,
patient
sonedadmission
that the the
cortical
areas involved to his right medial temporal lobe,
and fully cooperative. Immediate
awake,
with propositional
a strong¬ otherwise a fractional disorder of
recall was
reduced to language,
five numbers
for¬
dominant
function
of
the
left
hemi¬ recent memory should have occurred
ly
ward. Recent and remote memory, tested
wouldintact.
connect
sphere, were
preferentially
of
verbally,
Interpretation
(see "Comment" for clarification of
medial
lobe.
Thus this point).
to the left
into temporal
proverbs,
insight
illness, affect,
right/
a (verbal) recent memory loss occurred

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To my knowledge, the patients
described in this report with unilater¬
al loss of tactile recent memory estab¬
lish for the first time that fractional
disorders of recent memory can exist
in man. Although these patients are
unique in the clinical literature, I do
not think they are necessarily rare.
Since infarctions involving the poste¬
rior cerebral artery comprise approxi¬
mately 3% of occlusive strokes," if one
carefully screens for tactile recent
memory in patients with posterior
cerebral artery infarctions, fractional
disorders of recent memorv should be
readily encountered.
The technique of examining pa¬
tients for tactile recent memory loss is
straightforward and has been pre¬
sented in detail in the case reports.
Relatively nonverbalizable objects
should be used so as to force the
patient to make his choice based on
tactile features alone (Fig 1). If the
patient can easily verbalize or even
name the test object, then he might
use verbal rather than tactile recent
memory to correctly select the object.
Consequently, a disturbance of tactile
recent memory could be missed. To
establish that a patient has a loss of
tactile recent memory, it must be
shown that he has (1) no primary
problem with tactile perception, (2) no
aphasie disturbance that could inter¬
fere with testing, (3) normal tactile
immediate recall, and (4) normal tac¬
tile remote memory. If one can show
that the patient also has a retrograde
tactile amnesia, the syndrome would
be complete. Unless there are excep¬
tional circumstances, however, I doubt
that this phenomenon will be ob¬
served.
The lesions encountered on CT scan
in cases 2 and 3 involved the right and
left medial temporal lobes, respective¬
ly. These areas of the brain are tradi¬
tionally associated with recent memo¬
ry function,7 whereas the patients
with isolated loss of visual recent
memory described in the previous
report1 had bilateral lesions that did
not involve the medial temporal lobes.
To understand why fractional distur¬
bances of recent memory occur, the
reasoning put forth by Geschwind and
Fusillo11 concerning the (verbal) recent
memory loss observed in their patient
with a left medial temporal lobe
infarction is of relevance. They rea¬
soned that the cortical areas involved
with propositional language, a strong¬
ly dominant function of the left hemi¬
sphere, would preferentially connect
to the left medial temporal lobe. Thus
a (verbal) recent memory loss occurred

tions11"13 indicate that similar observa¬

Fig 4.—Idealized illustration showing presumed anatomical routes taken by auditory,
somatosensory, and visual information when coursing to medial temporal lobes in man.
Sensory information processed within hemisphere preferentially connects to ipsilateral
medial temporal lobe (solid black arrows). Ipsilateral hemisphere also has weak commissural connections (open dashed arrows) to opposite medial temporal lobe. Following
medial temporal lobe infarction, these weak commissural connections eventually allow the
lesioned hemisphere to once again access neuronal systems involved with recent memory
functions (see references 9 through 13 for direct anatomical and behavioral evidence for
above schema in monkey). Key to Figure is as follows: S, sorrjesthetic cortex; A, auditory
cortex; V, visual cortex; MT, medial temporal lobe.
because the language cortices had
been deprived of the neuronal struc¬
tures they normally connect to for
recent memory functions. The (verbal)
recent memory loss was transient
because the cortical areas involved
with language eventually strength¬
ened their commissural connections,
either through the callosum or the
anterior commissure, and gained ac¬
cess to the right medial temporal
lobe.
If Geschwind and Fusillo's thesis is
correct, then it would follow from
these cases with unilateral losses of
tactile recent memory that somesthet¬
ic, auditory, and by inference, visual
information being processed within a
hemisphere would preferentially con¬
nect to the ipsilateral medial temporal
lobe (Fig 4). Therefore, an acute left
medial temporal lobe lesion gives rise
to a right tactile loss of recent memo¬
ry, in addition to a verbal recent mem¬
ory loss. An acute right medial tempo¬
ral lobe lesion gives rise to a left

tactile recent memory loss and might
also cause a recent memory distur¬
bance for the postulated dominant
auditory functions of the right hemi¬
sphere, eg, the perceptions of music
and the prosodie elements of spoken
language.28 Although it was not
observed in this series of patients, one
can infer that a contralateral distur¬
bance of hemivisual recent memory
might also occur following an acute
medial temporal lobe lesion. Whether
fractional disorders of recent memory

involving hemivisual, melodic, or pro¬
sodie processing exist remains to be
discovered. If we now turn to animal
studies, there is some direct anatomi¬
cal and behavioral evidence to support
the proposed mechanism of fraction¬
al recent memory loss observed in
man.

Much of the work defining the role
of the temporal lobes and the cerebral
commissures in recent memory has
been studied in the visual system of
monkey,"1" but a number of publica-

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tions hold true for the somatosensory
system. The reports by Mishkin" and
co-workers have been the most de¬
tailed. In their experiments, lesions
were made in three stages: unilateral
inferotemporal ablation, followed by
contralateral occipital lobectomy, and
finally division of the corpus callosum.
After unilateral inferotemporal le¬
sions, the monkeys could easily relearn a previously taught visual dis¬
crimination. Following contralateral
occipital lobectomy, however, the
monkeys were found to have marked
impairment in relearning the recently
taught visual discrimination. This
observation was interpreted by Mish¬
kin" and co-workers to indicate that
the preserved striate and contralater¬
al inferotemporal connections were
not very well integrated when com¬
pared with the ipsilateral striate-inferotemporal connections (also shown
by Ettlinger14). When these animals
were retested just prior to callosal
section, their ability to relearn the
recently taught visual discrimination
was found to be as good as in the
controls. This suggested that the
crossed striate-inferotemporal con¬
nections could be strengthened in
time to allow the monkey to regain
normal visual learning capacity in the
preserved hemifield. After callosal
section, however, these animals could
not relearn the recently taught visual
discrimination, which offered proof
that the corpus callosum was the route
used for getting visual information
into the contralateral inferotemporal
cortex and, hence, into the medial
temporal lobe. Although Mishkin" and
Mishkin and Pribram15 have reported
that a unilateral temporal lobectomy
or a unilateral ventrohippocampal or
inferotemporal ablation does not re¬
sult in visual learning deficits, they
did not test their animals tachistoscopically in the right and left visual
fields for a possible (contralateral)
hemivisual recent memory distur¬
bance.
The publications by Semmes et al,"
Deuel et al,12 and Keating and Horel1 '
shed some light on the anatomical
substrates of tactile learning in mon¬
keys. Semmes et al" have established
that monkeys undergoing unilateral
temporal lobectomy and division of
the cerebral commissures manifest
profound difficulties in learning new
tactile discriminations in the hand
contralateral to the lobectomy. In a
follow-up study by Deuel et al,12 it was
found that unilateral temporal lobec¬
tomy alone did not produce a contralateral deficit in learning new tactile
discriminations. However, they tested

their monkeys four weeks after lobec¬
tomy, and it is quite possible that the
experimenters missed a transient tac¬
tile recent memory disturbance. In the
experiments done by Keating and
Horel,13 tactile testing in lesioned
monkeys was started the day after
surgery. Three of the monkeys under¬
went unilateral temporal lobectomy
and were tested for retention of a
previously overlearned tactile discrim¬
ination task in the contralateral hand.
Except for a moderate loss of per¬
formance in one animal, the other two
had fully retained the task. As dis¬
cussed by the authors in another sec¬
tion of their publication, retention of a
previously learned discrimination
task, especially when extensive preop¬
erative training has been done, is
often unaffected by temporal lobe
lesions, while the ability to learn a
novel discrimination task may be

severely compromised.1* (Presumably,
this dichotomy occurs because over-

learned discriminations involve re¬
mote memory functions, whereas tem¬
poral lobe lesions cause deficits in
recent memory functions.1718 Since
Keating and Horel did not test for
novel tactile discrimination learning
in their monkeys with unilateral tem¬
poral lobectomies, the question of
whether a transient contralateral loss
of tactile recent memory could occur
in monkey as it does in man remains
unanswered. Nevertheless, the above
experiments lend anatomical and be¬
havioral support to the thesis pro¬
posed in this report concerning the
mechanism for, and the recovery
from, fractional disorders of recent
memory that follow acute unilateral
lesions of the medial temporal lobe in
man.

The last point I wish to discuss

concerns some observations made

by
Bogen'" regarding a patient (first
illustrative case) who underwent cere¬
bral commissurotomy for the control
of seizures at age 27. The patient had
suffered from severe convulsions
since age 12, with numerous EEGs
'

demonstrating disorganization over
both hemispheres but maximum disor¬
ganization over the left temporal
region. After surgery, besides having
transient mutism and other expected
commissural deficits, he was discov¬
ered to have a profound loss of recent
memory (tested verbally). Although

tactile and visual recent memory were
tested, it was noted that the
patient could visually recognize his
physician even though he could not
remember his name. I believe the
recent memory disorder following
commissurotomy in this patient can
be explained if one assumption is
not

allowed—the seizure disorder was
caused by a long-standing left medial
temporal lobe lesion. This is a reason¬
able assumption, in view of the pre¬
dominant left temporal disorganiza¬
tion seen on EEG and the data pub¬
lished by Falconer et al20 concerning
the high incidence of lesions found in
the temporal lobes of "temporal lobe"
epileptics who have undergone lobec¬
tomy for seizure control. If this were
the case, then Bogen's patient might
have been forced to rely exclusively on
his right medial temporal lobe for
recent memory functions. Since the
postoperative commissural deficits
confirmed that propositional lan¬
guage was predominantly a function
of his left hemisphere, cerebral com¬
missurotomy probably caused his lan¬
guage areas in the left hemisphere to
become disconnected from his right
medial temporal lobe, which precipi¬
tated a profound loss of verbal recent
memory. Whether this patient dis¬
played a right tactile recent memory
loss or a right hemivisual recent mem¬
ory loss is not known. Nevertheless,
the phenomena observed in this

patient following commissurotomy
can be readily explained by the mech¬
anisms proposed in this discussion
regarding the cerebral commissures
and recovery from fractional recent
memory disturbances.
CONCLUSION

The

patients

described in

this

report illustrate and establish that

fractional disorders of recent memory
can exist in man. The underlying ana¬
tomical denominator in all three cases
was an acute unilateral lesion of
medial temporal lobe. Presumably,
this caused the ipsilateral sensory cor¬
tices to become deprived of their
normal access to brain areas necessary
for recent memory function, and frac¬
tional disorders of recent memory
resulted. The critical role of the cere¬
bral commissures in allowing recovery
from fractional recent memory distur¬
bances has been explored. Although
not encountered in this series of
patients, an appropriate unilateral
lesion not involving medial temporal
lobe might also give rise to a fraction¬
al disorder of recent memory by pro¬
ducing a disconnection between the

ipsilateral visual, auditory, or somato¬
sensory cortices and the ipsilateral
medial temporal lobe. Whether the

theses put forth in these two reports
concerning the anatomical substrates
of sensory specific and fraction disor¬
ders of recent memory will stand the
test of time depends on further clinicopathologic correlations in both man
and monkey.

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I thank Norman Geschwind, MD, Roger Rosen¬
berg, MD, and Stephanie Ross, MS, for their

critical and constructive review of the manu¬
script; Gary Tunell, MD, and Stephen Busby, MD,
for bringing my attention to cases 1 and 3,
respectively; Jan Diehl, MD, for his assistance in
interpreting the CT scans; and Denise Wernet
for patiently typing and retyping the manu¬

script.

References
1. Ross ED: Sensory-specific and fractional
disorders of recent memory in man: I. Isolated
loss of visual recent memory. Arch Neurol

37:197-200, 1980.
2. Bever TG, Chiarello RJ: Cerebral dominance

in musicians and nonmusicians. Science 185:537\x=req-\

539, 1974.

3. Geschwind N, Fusillo M: Color naming deficits in association with alexia. Arch Neurol
15:137-146, 1966.
4. Benson DF, Marsden CD, Meadows JC: The
amnesic syndrome of posterior cerebral artery
occlusion. Acta Neurol Scand 50:133-145, 1974.
5. Paterson A, Zangwill OL: Recovery of spatial orientation in the posttraumatic confusional
state. Brain 67:54-68, 1944.
6. Carter AB: Clinical aspects of cerebral
infarction, in Vinken PJ, Bruyn GW (eds): Handbook of Clinical Neurology. Amsterdam, North\x=req-\
Holland Publishing Co, 1972, pp 292-326.
7. Milner B: Amnesia following operation on
the temporal lobes, in Whitty CWM, Zangwill OL
(eds): Amnesia. London, Butterworth and Co
Ltd, 1966, pp 109-135.
8. Ross ED, Mesulam M-M: Dominant language functions of the right hemisphere? Prosody and emotional gesturing. Arch Neurol 36:144\x=req-\
148, 1979.
9. Mishkin M: Visual mechanisms beyond the
striate cortex, in Russell RW (ed): Frontiers in
Physiological Psychology. New York, Academic
Press Inc, 1966, pp 93-119.
10. Gazzaniga MS: Interhemispheric communication of visual learning. Neuropsychologia 4:183\x=req-\

189,1966.

11. Semmes J, Mishkin M, Deuel R: Somesthetic discrimination learning after partial nonsensorimotor lesions in the monkey. Cortex 5:331-350,

1969.
12. Deuel RK, Mishkin M, Semmes J: Interaction between the hemispheres in unimanual
somesthetic learning. Exp Neurol 30:123-138,
1971.
13. Keating EG, Horel JA: Somatosensory
deficit produced by parietal-temporal cortical
disconnection in the monkey. Exp Neurol 33:547\x=req-\
565, 1971.
14. Ettlinger G: Visual discrimination following successive temporal ablations in monkeys.
Brain 82:232-250, 1959.
15. Mishkin M, Pribram KH: Visual discrimination performance following partial ablations of
the temporal lobe: I. Ventral vs lateral. J Comp
Physiol Psychol 47:14-20, 1954.
16. Chow KL, Survis J: Retention of overlearned visual habit after temporal cortical ablation in monkey. Arch Neurol Psychiatry 79:640\x=req-\
646, 1958.
17. Stepien LS, Cordeau JP, Rasmussen T: The
effect of temporal lobe and hippocampal lesions
on auditory and visual recent memory in monkeys. Brain 83:470-489, 1960.
18. Dean P, Weiskrantz L: Loss of preoperative habits in Rhesus monkeys with inferotemporal lesions: Recognition failure or re-learning
deficit? Neuropsychologia 12:299-311, 1974.
19. Bogen JE: Linguistic performance in the
short-term following cerebral commissurotomy,
in Whitaker H, Whitaker HA (eds): Studies in
Neurolinguistics. New York, Academic Press
Inc, 1976, vol 2, pp 193-224.
20. Falconer MA, Serafetinides, Corsellis JAN:
Etiology and pathogenesis of temporal lobe epilepsy. Arch Neurol 10:233-248, 1964.