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Brainstem auditory evoked response in adrenoleukodystrophy.

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Brainstem Auditory
Evoked Response in
Adrenoleukodystrophy
James A. Black, MD, Ruggero G. Fariello, MD,
and Raymond W. Chun, M D
Clinical, laboratory, and electrophysiological data, including brainstem auditory evoked responses, are reported in a case of adrenoleukodystrophy. A striking
asymmetry was noted in wave VI of the brainstem auditory evoked potential, followed by absence of any
recognizable wave on the abnormal side. The presumed site of origin of wave V I is the medial geniculate body, a structure severely involved in adrenoleukodystrophy. It is suggested that the brainstem
auditory evoked response may promise noninvasive
diagnostic aid in this disorder and that absence of wave
VI may emerge as a clinically useful finding in diseases of the central nervous system.
Black JA, Fariello RG, Chun RW: Brainstem auditory
evoked response in adrenoleukodystrophy.
Ann Neurol 6:269-270, 1979
W e have recently had the opportunity to study a patient with adrenoleukodystrophy in whom an abnormality of brainstem auditory evoked potentials was
noted. Given the rarity of the disorder, we report this
case in the hope that our findings may stimulate further studies and contribute to early diagnosis by a
noninvasive technique.
A 734-year-old boy presented for evaluation of dementia,
behavior changes, apparent hearing loss, and gait ataxia of
approximately eight months' duration. Until this illness he
had developed normally. The faniilp history indicated a
sex-linked recessive disorder manifested as neurological o r
adrenal disease. O n examination the child appeared alert
and in apparent general good health. A hearing deficit was
present in both ears and he appeared to be mildly aphasic.
There was mild dysarthria. Mild dysdiadochokinesia and
truncal ataxia were noted. Reflexes were symmetrical. Pertinent data accumulated while in the hospital included adrenal unresponsiveness to administration of adrenocorticotropic hormone and abnormal C T scanning, which
showed symmetrical decreased attenuation in the parietooccipital regions that enhanced upon contrast administration,
From the Department of Neurology, University o f Wisconsin
School of Medicine, Madison, WI.
Accepted for publication Mar 27, 1979.
Address reprint requests to Dr Fariello, Department of Neurology, Clinical Sciences Center, 600 Highland Ave, Madison, WI
53792.
The electroencephalogram was abnormal on two occasions and indicated fairly well preserved background
rhythms in the anterior, central, and temporal regions, with
bilateral slowing and high-voltage sharp waves occurring
symmerrically but independently in the parietal and occipital leads (Fig 1). Cerebrospinal fluid was normal. Visual
evoked responses could not be elicited due to lack of cooperation from the patient. The brainstem auditory responses
were of interest (Fig 2). The latencies ofwaves I through V
were normal bilaterally. O n repetitive trials, waves VI and
V11 were consistently absent on the left. Actually, after
wave V there were no identifiable waves on the left even
when the time of analysis was extended to 80 msec. A
diagnosis of adrenoleukodystrophy was made. He continues t o deteriorate.
Discussion
Adrenoleukodystrophy is a rare, sex-linked, genetically transmitted multisystem disease involving most
conspicuously the central nervous system and the adrenals. It is now widely recognized that the majority
of male children usually diagnosed as having Schilder
disease probably suffer from adrenoleukodystrophy.
A rather characteristic C T presentation has been
identified [ 11, and early diagnosis depends o n recognition of the clinical presentation and a positive family history [ 3 ] .The value of adrenal or testicular biopsy has been recognized [ 31. Pathological findings in
postmortem material have documented severe neuron loss in the medial geniculate body in several patients 131.
Wave VI of the brainstem evoked response has
been postulated to originate partially in the thalamus,
possibly in the vicinity of the medial geniculate body
[4].
Recent depth electrode studies in humans have
substantiated this hypothesis [6].Since waves VI and
VII are sometimes asymmetrical in normal patients
[2], their unilateral absence is thought to be of questionable clinical relevance [ 21 unless longitudinally
studied [4, 51. Nevertheless, we believe that the absence of these waves in our patient is clinically important. No recognizable waves followed wave V on
the left, even when the time analysis was extended to
80 msec. By expanding the time analysis, we showed
absence of the middle latency component of the auditory evoked potential o n the left, indicating that
the auditory pathway on that side was probably interrupted at the level of the medial geniculate body and
no auditory information proceeded beyond that
point .
We have had no opportunity to study similar patients with adrenoleukodystrophy. Based on a single
observation, statements or generalizations on the
meaning of our findings would be inappropriate.
Confirmation of our results in other patients, however, would have a double relevance. From a physiological standpoint, it would prove that wave VI
0364-51 ~4/7')/0')02(,9-02$01.25@ 1979 by Ruggero G. Fariello 269
originates in the medial geniculate body in humans;
on clinical grounds, it would establish the diagnostic
usefulness of wave VI of the brainstem auditory
evoked potential, thus contributing to early diagnosis
of adrenoleukodystrophy through a simple, noninvasive electrophysiological technique with results independent of the patient's state of alertness o r cooperation.
References
1. Greenberg HS, Halverson D, Lane B: CT scanning and diagnosis of adrenoleukodystrophy. Neurology (Minneap) 27:
884-886, 1977
2. Rowe MJ: Normal variability of the brainstem auditory evoked
response in young and old adult subjects. Electroencephalogr
Clin Neurophysiol 45:459-470, 1978
3. Schaumberg H H , Powers JM, Raine CS, et al: Adrenoleukod ystrophy . Arch Neurol 33: 57 7-591. 1975
4. Stockaril JJ, Rossiter VS: Clinical and pathological correlates of
brainstem auditory response abnormalities. Neurology (Minneap) 27:316-325, 1977
5. Stockard JJ, Stockard JE, Sharbrough FW: Neuropathologic
factors influencing brainstem auditory evoked potentials. Am J
EEG Techno1 18:177-209, 1978
6. Tsubokawa T , Nishimoto H, Moriyasu N: Far-held responses
of acoustic brain stem potentials in the thalamus and the subrhalamic area. Neurol Med Chi, (Tokyo) 18:part 1:1-3, 1978
270 Annals of Neurology
F i g I . Electroencephalogramrecorded during drowsiness. The
tracing shows normal rhythm i n the anterior and central head
regions. Posterior temporal and parietal areas demonstrate predominant theta and delta actizdy bilaterally with occasional
sharp features. (Calibration signal: 1 ser, 50 p.)
Left
80db
Right 80 d b
I
I
I
3
I
V
I
1
6
I
9
I
I
12
I-?
I
15
msec
F i g 2. Brainstem auditory euoked potentials jhonz the right and
lejt ears, induced by high-frequency click t0ne.r at 80 db. Note
the absence of any recognizable wave VI on the l4t following
peaks IV and V (5.0 and 5.8 msec latencies, respectively).A
u/ell-defned wave VI i s Seen On the right at 7.6 msec.
Vol 6 No 3 September 1979
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response, adrenoleukodystrophy, auditors, brainstem, evoked
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