Journal of the Neurological Sciences, 1980, 48:35-49

35

© Elsevier/North-Holland Biomedical Press

CORTICAL DEAFNESS
A Case Report and Review of the Literature

JOHN GRAHAM*, RICHARD GREENWOOD** and BRYAN LECKY***

Departments of Otolaryngology and Neurology, The Middlesex Hospital, London W1 (Great Britain)
(Received 22 January, 1980)
(Revised, received 7 May, 1980)
(Accepted 13 May, 1980)

SUMMARY

A 48-year-old woman with triple cardiac valve prostheses became completely
deaf after bitemporal embolism. The lesions were demonstrated radiologically and
neurophysiological investigation confirmed intact peripheral and brainstem pathways. Experimental studies of the auditory pathways are briefly reviewed. Reported
cases of cortical deafness are discussed and the rarity of the condition emphasised.

INTRODUCTION

The primary auditory cortex of both man and animals is located in the
anterior and posterior transverse temporal gyri of Heschl. Each ear has bilateral
representation in the cerebral cortex and it is possible to remove the whole of
the human non-dominant hemisphere without significant effect on either the pure
tone audiogram or the discrimination of undistorted speech (Dandy 1933).
Considerable information in man has been derived from open brain stimulation
(Penfield and Perot 1963) and open brain recording of auditory evoked potentials
(Celesia 1976). Thus Penfield and Perot (1963) found that stimulation of the
anterior transverse temporal gyrus elicited simple auditory sensations such as
buzzing, whistling or knocking, while stimulation of surrounding areas including
the posterior two thirds of the superior temporal gyrus elicited complex auditory
hallucinations. Celesia (1976) confirmed the bilateral representation of the cochlea
but obtained larger amplitude responses from the contralateral ear. He found a
Present addresses: *University College Hospital, London WC1; **The National Hospitals for
Nervous Diseases and ***The Institute of Neurology, London WC1.

36
larger area surrounding the primary auditory cortex extending to the posterior two
thirds of the superior temporal gyrus and the upper bank of the Sylvian fissure
including frontal and parietal operculi where potentials of longer latency and
smaller amplitude were recordable. It is known that fibres project to these areas
from the medial geniculate bodies but little is known of the pathways or fate of
either commissural or efferent fibres. It seems that cortical lesions which result in
deafness must then be bilateral. The occurrence of such lesions in man sufficiently
circumscribed to avoid gross deficit in other functions is rare.
In animals, bilateral ablation so that no cortex responsive to auditory stimuli
remains and complete degeneration of the medial geniculate bodies occurs, results
in inability to detect changes in the temporal pattern of tones (Diamond and Neff
1957) or change in stimulus duration (Scharlock et al. 1965) but the ability to detect
the onset or changes in the frequency or intensity of sounds is retained (see
Scharlock et al. 1965 for references). It should be noted, however, that there may
be some difference between experimental cortical ablation and infarction in the
human as the latter may also include subcortical white matter.
Auditory deficits in man resulting from purely cerebral lesions are various.
The theoretical possibilities have been clarified by Earnest et al. (1977). Each case
shows variable contamination with deficit in speech or other cortical function.
Unilateral lesions of the temporal lobe cortex result in subtle auditory deficit. This
may consist of difficulty in discrimination of distorted, interrupted or accelerated
speech presented to the contralateral ear (Jerger 1960) or in localising sound in the
contralateral auditory field (Sanchez-Longo and Forster 1958). By contrast, a unilateral dominant temporal lobe lesion resulting in pure word deafness may leave
sound localisation quite unaffected (Gazzaniga et al. 1973). Such a lesion, which
may be cortical or subcortical, is thought to isolate Wernicke's area from the ipsilateral and contralateral auditory cortex. An auditory agnosia for speech results so
that the patient is unable to identify spoken words despite recognising that the
sounds represent speech. An adequate neurophysiological description of such cases
does not yet exist.
Pure word deafness is more commonly the result of bilateral lesions of the
superior temporal cortex (Goldstein 1974). Where documentation exists, such cases
usually show some degree of audiometric deficit (Jerger et al. 1972; Kanshepolsky
et al. 1973). Similar bitemporal lesions may result in an agnosia for both pure tones
and speech (Wohlfart et al. 1952; Lhermitte et al. 1971) or pure tones alone (Albert
et al. 1972). These cases also showed some primary audiometric deficit. If, in such
a case of bilateral cortical disturbance, the primary hearing deficit predominates,
then true cortical deafness may be said to exist. In some cases of cortical hearing
disorder, a true cortical deafness has been observed to resolve gradually into a
residual agnosia for speech and other sounds with only minor residual audiometric
deficit (Jerger et al. 1969; Goldstein et al. 1975). The relationship of pure word
deafness (auditory agnosia) to cortical deafness may thus be regarded as relative
rather than absolute. It has, in fact, been suggested that the 2 conditions represent
part of a general cortical hearing disorder (Goldstein 1974).

37
Reports of cases with bilateral cortical lesions resulting in true deafness are
rare. They begin with those of Wernicke and Friedl/inder (1883). This, and 2 other
early reports, are reviewed by Bastian (1897). Modern neurophysiological and
radiological tests were not available, confirmation of the site of lesions being
obtained at post mortem examination. The first results of neurophysiological
investigations in such a case were reported by Jerger et al. (1969). Radiological
evidence in a second case was reported by Earnest et al. (1977). We wish to report
the results of neurophysiological and radiological studies in a further case of total
deafness due to bilateral temporal lobe lesions.

CASE REPORT
Mrs. S. T., a 48-year-old right-handed white housewife presented to the
cardiac department at the Middlesex Hospital in 1974 with a 6-year history of
increasing dyspnoea and fatigue. She was noted to have rheumatic aortic, mitral and
tricuspid valvular disease and to be in atrial fibrillation. Despite treatment with
frusemide and digoxin she remained in gross congestive cardiac failure and, on
26.2.75, following cardiac catheterisation, she underwent triple valve replacement
with Starr-Edwards prostheses. Post-operative recovery was uneventful and she
was discharged home on 17.3.75 taking digoxin, frusemide, spironolactone and
warfarin.
She was readmitted on 20.5.75 with a 2-day history of headache and confusion.
She remained in atrial fibrillation but there were no signs of heart failure. She was
noted to have a severe conduction dysphasia, but no other neurological signs. A
technetium brain scan showed increased left temporal uptake and EEG showed
excess theta and delta wave activity in the left frontotemporal region. Dipyridamole
was added to her warfarin anticoagulation, which remained well controlled. At
out-patient review on 16.7.75 she was noted to have a left homonymous hemianopia
but the dysphasia had improved. She had reverted to sinus rhythm.
She remained well until March, 1976 when she was admitted to another
hospital following 2 grand mal fits. Mild dysphasia remained but no new neurological deficit was found. The dipyridamole was discontinued but the other
medication maintained.
In May 1977 she was readmitted to the same hospital following a further grand
real fit. Again, no new signs were found and the anticoagulation was well controlled.
A technetium brain scan was normal and EEG again showed a left temporal excess
of slow wave (2-5 Hz) activity.
A further grand real fit occurred in December 1977, following which her
husband noted that she was forgetful, being unable, for example, to prepare meals
reliably. Then, on 4.1.78, while alone in a room, she was heard to cry out and shortly
afterwards she was found to be totally deaf. Over the next few days she became
increasingly agitated and violent, refusing to consult the family doctor. She remained
deaf and her increasingly severe behavioural disturbance with paranoid ideas

38
necessitated her admission to a local psychiatric hospital on 14.2.78, from where
she was transferred to the Middlesex Hospital on 20.2.78.
She had received no anticonvulsants nor any ototoxic drugs. There was no
family history of deafness with the exception of a maternal grandmother who had
developed deafness at the age of 20 and of whom no details were available. There
was no past history of head injury, of occupational noise exposure or of psychiatric
disturbance.
On admission she was afebrile. The blood pressure was 140/90 and she was
in sinus rhythm. There were signs of normal prosthetic valve function and no signs
of heart failure.
General neurological examination revealed a left homonymous hemianopia to
menace with normal optokinetic responses to a hand held drum. Apart from deafness, there were no other cranial nerve abnormalities. Her gait was normal and there
was no disturbance of tone, power or voluntary movement in the limbs. She was
able to execute skilled tasks such as peeling an orange without difficulty. The
tendon reflexes were symmetrical and both plantar responses were flexor. The
sensory examination was normal, there was no astereognosis or tactile inattention
and graphaesthesia was normal.
She was orientated in place but, although able to state the day of the week,
was unable to name the month or year. She would sit quietly but at times appeared
agitated and perplexed, spontaneously uttering comments such as "what are they
saying?" or "did she say something?". At times she showed paranoid ideas referring
to bribery and attemped physical or sexual assault. She appeared totally deaf with
no startle response to loud sounds. Later, as she became less agitated, she appeared
to become aware that she was deaf and was distressed by this.
Her speech was of normal loudness but somewhat monotonous. It was fluent
but showed occasional neologisms, paraphasias, and inappropriate and ungrammatical word usage. There were frequent dysphasic errors in naming common
objects presented visually or by touch, e.g. "bricket" for button and "nickin pin"
for scissors. She was able to read but had great difficulty with words of irregular
spelling which she read phonetically. She could understand and execute simple
written commands but was unable to understand more complex sentences. She
could understand gestures and also use them for communication but the amount
of kinetic and mimetic play was limited and restrained.
Writing was performed hesitantly only with much persuasion and showed
spelling errors with preservation o f script both in spontaneous writing and in
copying. She could correctly add and subtract single figures but would not attempt
more complex calculations. Graphical constructional ability was not testable because
of apparent failure to understand the tasks. Kohs' blocks were assembled slowly
but correctly. There were errors in naming colours.
During all these tests her performance was contaminated by quite marked
perseveration.

39

Psychological assessment
Psychological assessment (Dr. E.K. Warrington, The National Hospital,
Queen Square, London) confirmed a global dysphasia in which expressive speech
functions were most impaired. The patient succeeded in naming 9/25 of the Oldfield
pictures, the errors consisting of both semantic approximations and literal paraphasias (e.g. Hat-Shoe, Horseshoe-Horse Cue). She scored 0/12 on Set 1 of the
Advanced Progressive Matrices, and did not appear to grasp what was required
of her. On the WAIS test of Block Design her score was well within the defective
range, even though she did not appear to have any primary spatial loss. It thus seemed
likely that there was also a moderately severe degree of generalised intellectual
impairment.

Investigations
The haemoglobin was 14.0 g/dl with normal platelet and differential white cell
count. The ESR was 20 mm/h. VDRL and TPHA were negative. Prothrombin time
was 34 s (control 12 s). Random blood glucose 4.4 mmol/1. MSU and blood cultures
were sterile. Serum urea, electrolytes, calcium, proteins, cholesterol, alkaline
phosphatase and aspartate transaminase were all normal. ANF was not detected.
X-rays of chest and skull were normal. The ECG showed sinus rhythm with
widespread ST-segment depression and T-wave inversion.
The EEG showed, in addition to the previously noted left-sided slow wave
abnormality, a right temporal excess of delta and theta activity with sharp waves.
Visual evoked responses were of normal latency. There was no psychogalvanic
skin response or attenuation of the EEG to sudden loud noise, but normal psychogalvanic skin responses were obtained to gasp and visual menace.
Transmission CAT scan of the brain (Fig. 1) showed discrete area of low
attenuation in both temporoparietal regions and in the right occipital region.

Neuro-otological assessment
Methods used were:

(1) Pure tone audiometry.
(2) Delayed speech feedback.
(3) Electric response audiometry (ERA) :
(a) Brainstem electric responses (BSER) : a series of 5 vertex-negative potentials
with a latency within 10 ms can be recorded in response to wide-band click stimuli
(Sohmer and Feinmesser 1967; Jewitt and Williston 1971; Lev and Sohmer 1972).
These potentials arise from the brainstem and it has recently been suggested (Starr
and Achor, personal communication) that they originate in the ascending fibre
tracts of the cochleocortical pathway from cochlear nerve to inferior colliculi.
(b) Middle latency response (Geisler 1960; Mendel and Goldstein 1969): the
most constant normal feature is a vertex-positive wave whose latency is 36 ms. It
has been the subject of controversy since it can be difficult to separate this neurogenic potential from myogenic reflex responses, and it may be hard to detect in
some normal subjects. It is thought to arise from the primary auditory projection
area, although there may be an earlier component from the thalamus.

Fig. 1. Transmission computer-assisted tomographic scan sllow,ing bilcmporal and i-iglll occipilal lcsione
of lov< attcnuatioll.

41
(c) Cortical ERA: this uses the slow vertex response or V-potential (Davis
1939; Gastaut 1953), a series of waves recorded over the vertex, The latency is
50-150 ms and their origin is the temporal lobe.
(4) Stapedius reflex: this is detected using the acoustic impedance bridge.
Bilateral contraction of the stapedius muscles occurs in response to a sound 70-90 dB
above subjective threshold.

Results
Assessment was performed during the first week of March 1978.
Pure tone audiometry showed no response from either ear up to 110 dB
hearing level (HL).
Delayed speech feedback testing showed no positive response using a feedback
delay of 0.2 s.
The BSER using wide-band click stimuli showed normal waveforms of normal
latency but with slight elevation of threshold at 45 dB H L bilaterally (Fig. 2). This
probably represents a minor pre-existing peripheral lesion and is consistent with
the patient's age. Cortical ERA showed no response from either ear using pure
tone bursts of 120 dB H L at frequencies of 500-400 Hz. Middle latency responses
were absent. Stapedius reflexes were present bilaterally although at slightly elevated
thresholds.

R

L
s

dB

4

90" "
80~

X

-'~'~'X2

80, ~ ~ j / ~

2

X2

70~"~'J~"~X2 70~ % X 2
60~

X

2

50~

X

2

60j ~ ~ ~ X 2
50~ , ' - ' ~ ' ~ ' ~ ~ X2

40~""~,~'~'~-~ X2 ~0 ~
0

10
ms

0

X

2

10
ms

Fig. 2. Brainstem-evokedresponses to 1024 averaged wide-band clicks at 40 90 dB. Wave 5 is clearly
shown and is detectable down to 50 dB. It is absent at 40 dB.

42

Progress
During her admission she became less agitated and her paranoid ideas subsided.
She remained totally deaf. She was treated with sodium valproate and trifluoperazine in addition to her pre-existing medication of digoxin and frusemide.
Warfarin and dipyridamole were continued and she was discharged home on
23.3.78.
She was admitted for reassessment on 23.5.78. Her husband reported no
recovery of hearing, although her mental state had become more tranquil. There
had occurred no further episodes of agitation or delusional thinking. She would
spend most of her day at home sitting quietly, often reading magazines or novelettes,
but her husband felt that she understood or retained little of the material read.
The cardiac signs were unaltered. She remained totally deaf. There had been
no change in her dysphasia. There was evidence of a mild left sided visual inattention
but no other focal neurological signs were found.
Her anticoagulation remained well controlled and routine haematological and
biochemical tests remained normal. Transmission CAT head scan showed no
significant change.
No response was obtained with pure tone audiometry. Cortical evoked
response audiometry gave no response to 120 dB tone bursts at 500, 1,000 and
2,000 Hz in either ear. Brain-stem electric responses to wide-band clicks gave
waveforms of normal latencies with, as before, slightly elevated thresholds of 45 dB
in the left ear and 55 dB in the right ear.
In August 1978, she developed tremor affecting all 4 limbs. The following
month she was admitted to another hospital, where she was felt to have developed
phenothiazine-induced Parkinsonism which was successfully treated by orphenadrine
and the withdrawal of trifluoperazine, only to become worse again when chlorpromazine was substituted because of behavioural problems.
She was reviewed again on 16.10.78. Her husband reported that at times she
was able to perceive loud noises, for example, looking up when the dog barked.
Most of the time, however, she seemed totally deaf and at no stage could she
understand speech.
Examination showed her to be agitated with some pressure of speech and,
again, evidence of delusional ideas of persecution. Her dysphasia, dysgraphia,
dyslexia and visual field defect were unchanged. There was still no clinical response
to the loudest sounds. There was mild intermittent rest tremor of all four limbs
associated with mild rigidity. The chlorpromazine was discontinued.
DISCUSSION

This patient is thought to have suffered 3 separate embolic lesions of cardiac
origin, the fin'st to the left temporal cortex producing dysphasia, the second to the
right occipital cortex causing a left homonymous hemianopia and the third, to the
right temporal lobe, resulting in total deafness. The first and third events represent
left and right middle cerebral artery embolism and the second, right posterior cerebral

43
artery embolism. Her 3 prosthetic valves continued to function satisfactorily and it
is possible that these disabling cerebral infarcts might have been prevented by the
permanent addition of dipyramidole to her warfarin anticoagulation (Sullivan et al.
1971).
For the first few weeks of deafness, she was agitated and paranoid. Indeed
the behavioural disturbance was so severe that admission to a psychiatric hospital
was required. This disturbance developed a few days after the deafness and
partially resolved after seven weeks. It was thought initially to be a reaction to
sensory deprivation and that the improvement coincided with increasing insight into
her disability. However, in previously reported cases of cortical deafness (Table 1),
behavioural problems of this type have not been mentioned, even when the deafness was complete (Earnest et al. 1977). Although the psychiatric effects of temporal
lobe infarction are not prominent (Williams 1969), when agitated delirium does
occur, infarction is found to be inferior and medial, in the territory of the posterior
cerebral artery, and to include occipital infarction (Horenstein et al. 1967; Medina
et al. 1977). As in this case, agitation tends to begin a few days after the lesion and to
resolve gradually. Our patient had sustained a right occipital infarct in 1975. It is
likely that the inferior and medial areas of the right temporal lobe were ischaemic
prior to the right middle cerebral artery embolus in 1978 and that the latter event
caused further inferior and medial temporal lobe ischaemia, in addition to lateral
and superior temporal lobe infarction, and caused her psychiatric disturbance.
The cases of auditory disorder resulting from bilateral hemisphere lesions in
the literature vary considerably in the stringency of their assessment. Only those
reported in the last 30 years were assessed audiologically. As already noted, the
deficit in most patients with a cortical hearing disorder has been agnosic. The
patient is unable to recognise spoken words, and perhaps also music and other
sounds, and may describe the disability with such words as "I can hear you talking,
but I can't translate it" (Jerger et al. 1972; Kanshepolsky et al. 1973). The primary
hearing deficit may be detected only on audiometry. Thus the patient reported by
Jerger et al. (1972), who at no time complained of frank deafness, had a bilateral
30 40 dB loss for pure tones. Speech audiometry using monosyllabic words showed
zero discrimination. He did, however, retain the ability to identify short sentences
(60~ discrimination in one ear, 30~ in the other) but this ability was lost if any
distortion was introduced. Similarly, Kanshepolsky et al. (1973) found a bilateral
increase in pure tone threshold of 10-30 dB, impaired loudness discrimination and
impairment of threshold-duration functions in their patient. However, modern
techniques have convincingly demonstrated that in a few cases a major primary
audiometric deficit does indeed exist. Such patients complain of being unable to
hear anything, including their own speech, and may thus be said to have true
cortical deafness.
Only 12 cases of significant deafness due to purely cerebral pathology have
been reported (Table 1), the majority before the introduction of modern audiology.
Early reports relied on post mortem confirmation of the lesions. The cases of
Wernicke and Friedl/inder (1883), Mills (1891), Pick (1892), Mott (1907), Bramwell

F

M

F

F (R)
M

F (R)

F

46

24

25

62
29

44

51
20

31

27

50

2. Mills (1891)

3. Pick (1892)

4. Mutt (1907)

5. Bramwell (1927)

6. Misch (1928)

7. Clark and Russell (1938)

8. Chavany (1945)

9. Jerger et al. (1969)

10. Goldstein et al. (1975)

11. Earnest et al. (1977)

12. Z611ner et al. (1977)

M/F indicate sex and R/L. a m b handedness, where known.
,L Indicates post-mortem examination performed.

? (L)

M (L)

F (L)

M (amb)

I. Rt. hemiparesis, aphasia, word
deafness
2. Lt. hemiparesis, total deafness

F

43

1. Wernicke and Friedl~inder (1883)

I. Transient aphasia
2. Deafness, Lt. hemiparesis

2. Aphasia, Rt. hemiparesis

arm

1. Dysarthria, paresis kt. facc and

1. Complete deafness, Lt. hum.
hemianopia, ext. plantar
response, amnesia etc.

1. Rt. hemiparesis, dysphasia
2. Complete deafness

1. Rt. hemiparesis, dysphasia
2. Lt. hemiparesis, deafness

1. Lt. hemiparesis
2. Deafness; bilat, extensor plantar
response
3. Fatal pontine haemurrhage

I. Endocarditis
2. Dysphasia, Rt. hemiparesis
3. Total deafness

I. Aphasia
2. Deafness

1. Transient aphasia
2. Rt. hemiparesis and aphasia
3. Paresis Rt. arm, n y s t a g m u s and
deafness

1. Rt. cerebral lesion
2. Lt. cerebral lesion with partial
and word deafness

1. Word deafness
2. Lt. hemiparesis and partial
deafness
3. Non-specific illness and total
deafness

Clinical events

Age (yr)/Sex

Authors

TABLE 1

Bitemporal lesions
probably infarction

Bitemporal infarction
on C A T scan, valvular
heart disease

Encephalitis

Bilat. distal middle
cerebral a. occlusion
on angiogram, '?cause

Hypertension

aBilat, infarction o f
external capsule.
Hypertension

aLt. cerebral haem.
Haem. infarct. Rt.
trans, temp. gyrus

~Bitemporal infarction.
Mitral stenosis

aBitemporal emboli.
Valvular heart disease

aBitemporal infarction

~Bitemporal infarction
valvular heart disease

dBitemporal infarction
?cause

Pathology

Few details. Marked
audiomctric loss.

Total deafness, rcco~ erx
to 65 8 0 d B I o s s

Total deafness ew)lvmg
to word deafness over
2 years

60-85 dB loss,
s o m e recuvery

Total. some recovery

Initially total, some
recovery

Total and permanent
(2 weeks)

Total a n d p e r m a n e n t
( l month)

Total and permanent
(7 years) but brainstem
signs

Partial

Total and p e r m a n e n t
(9 years) quotes 3 other
cases

Total and p e r m a n e n t
( 1 month)

C o m m e n t un deafness

45
(1927), and Misch (1928) demonstrated bitemporal infarction, with haemorrhage
in the last-mentioned case, involving at least the superior temporal gyri together
with varying extents of surrounding insular, parietal and temporal cortex. Where
the cause is given these lesions were due to cardiac emboli. The case of Clark and
Russell (1938) provides an exception, the responsible lesions being bilateral external
capsular infarctions in a hypertensive. The resulting interruption of the auditory
radiations, the postulated cause of the deafness, was demonstrated by degeneration
of the right medial geniculate body, the left having been disrupted by terminal
brainstem haemorrhage. Although the cerebral lesions appear to be sufficient to
cause the deafness in these cases, in none was the state of the brainstem or peripheral
pathways reported.
Further single case reports of clinical cortical deafness followed from Lemoyne
(1944) and Chavany (1945). The former case, briefly initially reported by Thi6baut
et al. (1944), was a 50-year-old woman whose deafness followed an episode of loss
of consciousness and epistaxis. There was mild dyscalculia but no other localising
signs. She was said to have an auditory agnosia and conductive hearing loss of
60-70 dB. There was no post-mortem examination. The cause of the deafness is
obscure, but we suggest that it could have arisen from blood in the middle ear.
Chavany's case, a 52-year-old hypertensive woman, suddenly became deaf prior to
the onset of a left hemiparesis having 18 years before recovered from a sudden
episode of dysphasia and right hemiparesis. Audiometry revealed significant sensorineural deafness. Although there were no reported brainstem signs, post-mortem
examination was not performed, and although likely to be cortical, the cause of
the deafness remains in doubt.
In 1952, Ziegler reported a 45-year-old man as a case of word deafness. The
patient was seen initially 10 days after an episode of numbness of both hands,
especially the right, accompanied by complete deafness. Four years before he had
suffered a brief episode of reading difficulty. At the time of examination his deafness
had resolved, word deafness and minor speech deficit remaining. No post-mortem
examination was carried out, but a cortical aetiology of the initial deafness is
possible. Lemoyne and Mahoudeau (1959) reported a case of "agnosie auditive pure
avec surdit6 cortical". However, although the patient had "l'impression d'etre
devenu sourd subitement", the authors went on to state that "en r6alit6, il entend
un 16ger claquement des doigts, le bruit fait par un trousseau de clefs, un 16ger
siffiement". In addition, audiometry showed no significant deficit. This would not
seem to be a case of true cortical deafness. A further case of cortical hearing loss was
reported in 1963 by Hansen and Reske-Nielsen, a patient with a right hemisphere
glioblastoma and cerebral oedema. The hearing loss, however, consisted of a minor
fluctuating audiometric deficit rather than clinical deafness.
The report of Jerger et al. (1969) finally provided documentation of unequivocal
deafness due to clearly demonstrated cortical lesions with no evidence of a peripheral
lesion. They reported audiological findings in a 20-year-old man with bilateral distal
middle cerebral artery occlusion of uncertain aetiology. The initial left lesion resulted
in a moderate expressive and receptive dysphasia with questionable right facial

46
weakness and mild sensory signs in the right arm. Two months later the signs had
resolved except for mild dysphasia. ]'he right-sided occlusion occurred 7 months
later and resulted in the sudden onset of deafness, apparently total, and without
additional deficit. Although the patient was unable to hear speech and other sounds
and did not respond to "relatively loud noises", audiometry on the day of admission demonstrated a bilateral sensorineural pure tone loss of only 60-85 dB.
Shortly after admission, electrodermal audiometry showed no response at any
frequency even at high sound levels. Over the next 3 months considerable improvement in pure tone audiometry occurred although marked loss at high frequencies
in the right ear persisted. Speech audiometry at 3 months showed 301'~;discrimination
in the left ear, opposite the less severely damaged cortex, and zero discrimination
in the right ear. Cortical ERA was performed and no responses were obtained
although the patient was able to hear the pure tone signal. No evidence of a peripheral
auditory lesion was found and the absence of brainstem involvement was argued
on clinical grounds.
Since 1969, there have been 4 further reports of interest. A patient with
bilateral temporal lobe infarcts reported by Jerger et al. (1972) did not complain
of deafness, rather reporting "I can hear you talking, but I can't translate it" and
showed only a 2 0 4 0 dB loss on pure tone audiometry. The patient reported by
Goldstein et al. (1975) was a 31-year-old woman with an encephalitic illness in
whom there was no evidence of labyrinthine or brainstem disease and whose
deafness was out of all proportion to other cortical deficit. Initially loud noises
produced no response but after the first day she began to turn her head towards
loud sounds although denying hearing them. Her hearing gradually improved over
a period of 2 years until she could react to environmental noise and identify nonverbal sounds but remained severely impaired in her recognition of speech and music.
Earnest et al. (1977) reported the case of a 27-year-old left-handed man with a
S t a r , E d w a r d s valve prosthesis who presented with complete deafness following a
right middle cerebral artery embolus. Four years previously he had suffered a left
middle cerebral artery embolus. The lesions were demonstrated on computerised
tomography (CAT scan). Immediately after the onset of deafness, pure tone audiometry showed no response while static compliance, tympanogram and stapedius
reflex testing were normal. Cortical ERA performed three months later gave
thresholds of 40-70 dB in each ear. Three years later, pure tone audiometry showed
variable thresholds which were never less than 65-80 dB and he remained unable
consistently to identify the nature, or even the presence, of sounds. Z611ner et al.
(1977) described a patient with bitemporal lesions, deafness (of unspecified severity),
marked pure tone audiometric loss, delayed and diminished cortical ERA (possibly
a response to vibration rather than auditory stimuli) and brainstem responses of
normal amplitude and latency, although of marginally elevated threshold. This
case almost certainly represents true cortical deafness.
The history of our patient is similar to that of the patient reported by Earnest
et al. (1977). Both patients were completely unresponsive to the loudest noises and
to pure tone audiometry. Our patient showed no response to delayed speech feed-

47
back and no psychogalvanic skin response or attenuation of E E G to sudden loud
sounds. It is of interest to note the absence of any startle response in these patients
since the startle reaction to acoustic stimuli is well known to occur in decorticate
primates and h u m a n anencephalics (see Larsson 1956). It is also apparent that purely
cortical lesions may result in total deafness, despite the statement to the contrary
by Howe and Miller (1975) and evidence from previously noted animal work
indicating that sound m a y be detected at subcortical levels.
The patient reported by Earnest et al. (1977) showed only slight recovery at
three years; our case has shown no improvement after nine months. The statements
by Jerger et al. (1972) and DiCarlo et al. (1962) that substantial hearing loss is not
a permanent consequence of bitemporal lesions must, therefore, be questioned.
Our patient showed normal stapedius reflexes and brainstem-evoked responses,
effectively demonstrating the normality of the peripheral auditory pathways as high
as the inferior colliculi. We believe our patient is the first with complete cortical
deafness in w h o m brainstem-evoked responses have been reported. The absence of
cortical E R A response is taken as confirming the cortical level of the auditory
pathway lesion. However, it is noted with some caution that the patient of Jerger
et al. (1969) showed no response on cortical E R A although able to hear the test
sound, whereas the patient of Earnest et al. (1977) showed responses, albeit at elevated
thresholds, but was unable to hear the stimulus.
Complete cortical deafness is therefore a most unusual event but is unquestionable as an entity. Our case illustrates nicely the use of modern audiological
techniques in determining the level of a lesion in the auditory pathway.
ACKNOWLEDGEMENTS
We thank Dr. C. J. Earl for permission to report this case and for advice and
encouragement, Dr. Macdonald Critchley and Dr. M. J. G. Harrison for seeing the
patient and for criticism of the manuscript, Mr. H . A . Beagley for his advice and the
assistance of the department of Electrophysiology at the Nuffield Centre for Speech
and Hearing, G r a y ' s Inn Road, London, and Miss A. Sayers and Miss E. Higgins
for kindly typing the manuscript.
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