SummaryAlterations in early auditory evoked potentials (EAEP) in individuals with demyelinating disease are suggestive of lesions in the brainstem.Aimthis study aims to evaluate the prevalence of hearing disorders and altered EAEP in multiple sclerosis (MS) patients.Materials and methodsixteen female and nine male patients with a defined diagnosis of multiple sclerosis took part in this study. All individuals underwent hearing and EAEP tests. The wave forms were categorized according to Jerger (1986).Resultsfifty EAEP tests were carried out; 70% were classified as type I (normal response) according to Jerger's criteria. Altered EAEP results in at least one ear were classified into types II, III, IV or V according to Jerger. Females accounted for 31.25% of alterations, and males 44.44%, adding up to 36% of all cases.Conclusionsthese findings stress the importance of looking at EAEP in cases where there is suspicion of demyelinating disease and in patients with a defined diagnosis for MS

Crato, Aline Nascimento

Gonçalves, Denise Utsch

Lima, Tania Mara Assis

Mancini, Patrícia Cotta

Simões, Lília Correa

Brazilian Journal of Otorhinolaryngology

Elsevier - Publisher Connector 

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Alterations in early auditory 
evoked potentials in multiple 
sclerosis patients
   Summary
Tania Mara Assis Lima1, Aline Nascimento Crato2, 
Patrícia Cotta Mancini3, Lília Correa Simões4, 
Denise Utsch Gonçalves5 
1 PhD in Otorhinolaryngology, Adjunct Professor in the Department of Otorhinolaryngology at FM UFMG.
 2 Speech and Hearing Therapist.
 3 MSc in Linguistics, Associate Professor in the Department of Speech and Hearing Therapy at FM UFMG.
 4 Speech and Hearing Therapist in the Audiology Ward at Hospital das Clínicas da UFMG.
 5 PhD in Tropical Medicine, Adjunct Professor in the Department of Otorhinolaryngology at FM UFMG.
UFMG Medical School, Hospital das Clínicas da UFMG.
Send correspondence to: Tânia Mara Assis Lima - Rua do Ouro 229/502 30220-000 Belo Horizonte MG.
This paper was submitted to the RBORL-SGP (Publishing Manager System) on 7 July 2007. Code 4645.
The article was accepted on 2 November 2007.
Alterations in early auditory evoked potentials (EAEP) 
in individuals with demyelinating disease are suggestive of 
lesions in the brainstem. Aim: this study aims to evaluate the 
prevalence of hearing disorders and altered EAEP in multiple 
sclerosis (MS) patients. Materials and method: sixteen 
female and nine male patients with a defined diagnosis of 
multiple sclerosis took part in this study. All individuals 
underwent hearing and EAEP tests. The wave forms were 
categorized according to Jerger (1986). Results: fifty EAEP 
tests were carried out; 70% were classified as type I (normal 
response) according to Jerger’s criteria. Altered EAEP results 
in at least one ear were classified into types II, III, IV or 
V according to Jerger. Females accounted for 31.25% of 
alterations, and males 44.44%, adding up to 36% of all cases. 
Conclusions: these findings stress the importance of looking 
at EAEP in cases where there is suspicion of demyelinating 
disease and in patients with a defined diagnosis for MS. 
Keywords: multiple sclerosis, auditory evoked potentials, 
brainstem.
ORIGINAL ARTICLE
Braz J Otorhinolaryngol.
2009;75(2):177-81.
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INTRODUCTION
Brainstem auditory evoked potentials (BAEP) are 
short latency potentials generated in the auditory nerve 
and in the auditory pathways of the brainstem as the 
cochlea is activated in frequencies ranging between 2000 
and 4000Hz after the introduction of sound stimuli. They 
are characterized by a series of positive peak waves that 
come up within the first 10 milliseconds (ms) and that 
represent the summation of the neural activity of one or 
more sites. The more important waves are the rising ones, 
namely I, III, and Vl.
BAEP results are altered in neurologic disorders 
introduced by tumors, diffuse lesions, demyelinating di-
seases, or functional disorders2.
Multiple sclerosis (MS) is the most common type 
of demyelinating disease and the main cause of neurolo-
gic damage in young adults. This is a slow, progressive 
disease that features periods of symptom exacerbation 
and remission3 and huge variation between individuals, 
depending on the site of the lesion4.
BAEP tests in individuals with demyelinating dise-
ase are important to assess central nervous system invol-
vement5. The incidence of altered results in MS patients 
reported in the literature varies considerably. Wave I is 
almost always normal in patients without hearing loss. 
The anomalies found in patients with MS include: prolon-
ged wave latency and intervals between peaks; reduced 
amplitude on wave V; reduced wave V/I amplitude ratio; 
absent wave V6.
The goal of this study is to assess the incidence of 
hearing disorders and altered BAEP test results in indivi-
duals with multiple sclerosis, looking at hearing thresholds 
and absolute latencies, intervals between peaks, wave 
characteristics, morphology and reproducibility.
MATERIALS AND METHOD
This study was approved by the UFMG-COEP Ethics 
Committee under permit 052/2004. Sixteen female and nine 
male patients from the Multiple Sclerosis Research Center 
(Centro de Investigação em Esclerose Múltipla - CIEM) 
were enrolled in the study. All had clinically defined diag-
nosis for multiple sclerosis according to the criteria set by 
Poser7. Clinical manifestations were categorized according 
to the principles proposed by Lubin and Reingold 8. The 
female patient group’s age ranged between 33 and 53 years 
(mean 42.6 years) while the male patient group was aged 
between 24 and 56 years (mean 38 years).
All patients were interviewed and underwent cli-
nical ENT examination, tympanometry, tone audiometry, 
and BAEP tests.
The criteria defined by Russo9 were used to sort 
tympanometry results. Audiometry results were classified 
according to the principles defined by Davis and Silver-
man10.
On the BAEP tests we used a sound stimulus of 
1024 clicks introduced by a TDH-39 rarefied polarity 
supra-auricular transducer in 100ms pulses, at 60dB of 
sound pressure level above the psychoacoustic threshold 
of each subject. Stimuli were presented in one ear at a 
time, masked by white noise in the contralateral ear at 
30dB SPL.
High pass filters at 3000Hz and low pass filters at 
100Hz were used. Clicks were introduced at a rate of 13.1/
sec on the right ear and then on the left ear.
The criteria defined by Munhoz11 were used to 
define normal BAEP findings.
Waves were categorized as defined by Jerger12:
Type I: normal response; all waves (I-V) had normal 
latencies and between peak intervals.
Type II: prolonged interval I-V.
Type III: degraded wave form; poor morphology; 
peaks hard to tell apart and/or reduced amplitude; and/
or altered amplitude ratios.
Type IV: absent last waves; absent last waves, first 
waves present with normal latency.
Type V: extremely altered response or only wave 
I normal.
RESULTS
Fifty-six percent of the 25 patients enrolled in the 
study had acute remissive MS, as shown in Table 1. Sixty-
eight percent of the patients had tone hearing thresholds 
within normal range, and other cases of hearing loss did 
not interfere with BAEP acquisition (Tables 2 and 3).
From the 50 BAEP tests done, 70% were catego-
rized as type I. Prolonged intervals between peaks I-V 
were found in 6.25% of the female subjects and 11.11% 
of the male patients, and they were categorized as type II. 
Wave form degradation and poor morphology was found 
in 5.55% of the male group, and they were categorized 
as type III. Type IV was not found. Type V, with more 
altered tracings, occurred in 18.75% of females and 22.22% 
of males (Table 4).
Subjects with types II, III, and IV were considered 
to have altered BAEP results in at least one ear. Thirty-
six percent of the patients had altered BAEP results, with 
incidences of 31.25% among females and 44.44% among 
males (Table 5).
Individual values of absolute latency and between 
peak intervals in MS patients can be seen on Charts 1 
and 2.
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Table 1. MS Clinical forms according to the Lublin and Reingold Classification
Gender
Female Masculino Total
Clinical form Male N % N %
Remission flare 62,50 4 44,44 14 56
Progressive flare 1 6,25 2 22,22 3 12
Secondary progressive 0 0 0 0 0 0
Primary progressive 5 31,25 3 33,33 8 32
TOTAL 16 100 9 100 25 100
N = number
Table 2. Hearing loss classification as to intensity according to Davis and Silverman
Females Males
RE LE RE LE
Classification N % N % N % N %
Normal 12 75 11 68,75 6 66,66 6 66,66
Mild 1 8,33 1 6,25 2 22,22 2 22,22
Moderate 3 16,66 4 25 1 11,11 1 11,11
Severe 0 0 0 0 0 0 0 0
Profound 0 0 0 0 0 0 0 0
TOTAL 16 100 16 100 9 100 9 100
N = number   RE: Right ear   LE: Left ear
Table 3. Tonal audiometry results according to Davis e Silverman
Females Males Total
Audiometry N % N % N %
Normal 11 68,75 6 66,66 17 68
Altered 5 31,25 3 33,33 8 32
TOTAL 16 100 9 100 25 100
N = number
Table 4. Classification of wave types according to Jerger
Females Males Total
N % N % N %
Type I 24 75,00 11 61,11 35 70
Type II 2 6,25 2 11,11 4 8
Type III 0 0 1 5,55 1 2
Type IV 0 0 0 0 0 0
Type V 6 18,75 4 22,22 10 20
TOTAL 32 100 18 100 50 100
N = number
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Table 5. Classification of BAEP in both genders
Females Males Total
N % N % N %
Normal 11 68,75 5 55,55 16 64
Altered 5 31,25 4 44,44 9 36
TOTAL 16 100 9 100 25 100
N = number
Chart 1. Individual values of absolute latencies and interpeak intervals of female individuals
Waves Interpeak intervals
I III V I-III III-V I-V
RE LE RE LE RE LE RE LE RE LE RE LE
1,52 1,56 3,44 3,40 5,52 5,72 1,92 1,84 2,08 2,32 4,00 4,16
1,48 1,76 3,28 3,52 5,20 5,72 1,80 1,76 1,92 2,20 3,72 3,96
1,60 1,60 3,48 3,52 5,48 5,60 1,88 1,92 2,00 2,08 3,88 4,00
1,68 1,72 3,88 3,96 6,00 5,92 2,20 2,24 2,12 1,96 4,32 4,20
1,56 1,56 3,88 3,80 5,28 4,88 2,32 2,24 1,40 1,08 3,72 3,32
1,44 1,76 3,44 3,44 5,16 5,72 2,00 1,68 1,72 2,28 3,72 3,96
1,56 1,72 3,68 3,52 5,56 5,72 2,12 1,80 1,88 2,20 4,00 4,00
1,64 1,60 3,88 3,80 5,84 5,92 2,24 2,20 1,96 2,12 4,20 4,32
1,68 1,56 3,84 3,80 5,36 5,36 2,16 2,24 1,52 1,56 3,68 3,80
- - - - - - - - - - - -
- - - - - - - - - - - -
1,64 1,80 3,48 3,60 6,24 5,88 1,84 1,80 2,76 2,28 4,60 4,08
1,60 1,40 4,16 3,60 6,24 5,28 2,56 2,20 2,08 1,68 4,64 3,88
1,12 1,16 2,80 2,84 4,64 4,76 1,68 1,68 1,84 1,92 3,52 3,60
1,36 1,36 3,56 3,48 5,60 5,44 2,20 2,12 2,04 1,96 4,24 4,08
RE: Right Ear  LE: Left Ear
Chart 2. Individual values of absolute latencies and interpeak intervals of males
Waves Interpeak Intervals
I III V I-III III-V I-V
RE LE RE LE RE LE RE LE RE LE RE LE
1,52 1,56 3,76 3,64 5,48 5,48 2,24 2,08 1,72 1,84 3,96 3,92
1,60 1,44 3,64 3,60 5,56 5,60 2,04 2,16 1,92 2,00 3,96 4,16
- - - - - - - - - - - -
1,12 1,12 3,28 3,20 5,32 5,32 2,16 2,08 2,04 2,12 4,20 4,20
1,48 1,60 3,80 4,52 5,96 6,80 2,32 2,92 2,16 2,28 4,48 5,20
1,48 1,64 3,84 3,72 5,80 5,80 2,36 2,08 1,96 2,08 4,32 4,16
1,40 - - - - - - - - - - -
1,40 1,24 3,76 3,84 5,12 5,92 2,36 2,60 1,36 2,08 3,72 4,68
1,48 1,48 3,64 3,84 5,80 5,92 2,16 2,36 2,16 2,08 4,32 4,44
RE: Right Ear  LE: Left Ear
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DISCUSSION
Hearing loss in MS is sensorineural and bilateral in 
85% of the cases3. In our study, tone audiometry results 
were altered in 32% (8) of the patients, with 87.5% ha-
ving bilateral sensorineural hearing loss and 12.5% being 
affected by moderate left conductive hearing loss due to 
ear drum perforation. Jerger12 reported altered audiometry 
results in 39% of multiple sclerosis patients, all of whom 
affected by sensorineural hearing loss.
MS neurologic symptoms are many, and may 
vary from case to case and throughout the progress of 
the disease. In Brazil, Lana-Peixoto and Lana-Peixoto13 
found brainstem alterations in 34% of the individuals 
with manifestations compatible with early MS and 45% 
with progressed disease. Papais-Alvarenga et al.14 found 
brainstem alterations in 28.4% of early MS patients and 
in 28.5% of patients with progressed MS. Tilbery et al.15 
found signs and symptoms of brainstem alteration in 32% 
of patients with early MS and in 52% of patients with 
progressed disease.
Our study showed altered BAEP in 9 patients (36%) 
in one or both ears, 31.25% of whom were females and 
44.44% males. In 66.7% of these patients, altered results 
were found in both ears. Jerger12 found 52% of BAEP alte-
ration in one or both ears, 68.75% of whom had bilateral 
hearing loss. Santos et al.16 found altered unilateral and 
bilateral results in 58.62% of the patients, 60% in females 
and 56% in males.
The most frequently found alteration in our study 
was type V12, as it occurred in 18.75% of females and 
22.22% of males. Jerger12 reported type II alteration in 
6.5%, type III in 8%, type IV in 16.1%, and type V in 13% 
of patients. Santos16 reported type II in 32.8%, type IV in 
5%, and type V in 7% of patients.
CONCLUSION
Thirty-six percent of the 25 patients with clinically 
diagnosed MS had brainstem alterations as found in BAEP 
tests, thus stressing the importance of this test in examining 
patients clinically suspected for demyelinating disease.
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Alterations in early auditory evoked potentials in multiple sclerosis patients 

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Alterations in early auditory evoked potentials in multiple sclerosis patients

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