Acoustic and vestibular function in multiple sclerosis

Electronystagmography in the diagnosis of multiple sclerosis

The aim of our study was to define the diagnostic importance of a complete electronystagmographic (ENG) examination (visual-vestibular, vestibular and visual suppression tests on caloric nystagmus) in patients affected by MS. Of 144 patients examined, 116 were definite and 28 possible. Descriptive data of the instrumental findings showed very frequent alterations of one or more subtests: pursuit movements and visual suppression test were especially pathological, in respectively 56% and 58% of the cases; spontaneous and/or evoked nystagmus was present in 45%. A comparison between clinical and instrumental evidence of brainstem/cerebellar involvement indicated that 18% of the definite and 32% of the possible MS cases presented a negative clinical examination with positive instrumental findings. The usefulness of including a comprehensive ENG examination to obtain paraclinical evidence of a second lesion in the CNS in early MS is discussed.

Auditory deficits in multiple sclerosis: a review

This article reviews available clinical and psychophysical data concerning the effects of multiple sclerosis (MS) on basic auditory processes. On the basis of the data, it is suggested that the presence of auditory deficits should be sought in MS patients. This is especially important in light of recent psychophysical evidence suggesting that subtle auditory problems present in affected individuals may not always be detectable via conventional clinical testing. These data also provide an alternate means of interpreting various aspects of impaired auditory functioning in MS patients, and aid in generating new hypotheses regarding the possible consequences of demyelination on normal auditory perception. Finally, new ways of testing such hypotheses are proposed, and possible directions for future research are suggested.

Evoked potentials. With special reference to the diagnostic value in multiple sclerosis

A survey is given of my studies of evoked potentials in patients with multiple sclerosis (MS) and in control subjects. Potentials were recorded following random low-rate auditory stimulation (BAEP), checker-board pattern-reversal stimulation (VEP), somatosensory stimulation (SEP); blink reflexes (BR) were recorded following electrical stimulation of the supraorbital nerve. Normal data had to be related to age and sex in evaluating BAEPs and VEPs. In 160 MS patients, a total of 421 recordings were obtained. Changes by repeated BAEP and VEP tests might reflect changes in the clinical state, but they also did occur in clinically stable patients. In patients with definite MS, high incidences of abnormality were shown, supporting the clinical findings. The diagnostic value was greatest when clinically silent lesions were demonstrated in patients with suspected or possible MS. In these patients, either BAEP or VEP gave evidence of subclinical lesions in about 50%, and when combined, in 71% of the patients, thus making a transfer to a more certain diagnostic classification possible and invasive examinations unnecessary. When SEP and BR tests were added, subclinical lesions were found in 74% of the patients. The SEP recordings did show a high incidence of abnormality, but only few silent lesions; the BR test was the least sensitive. The VEP was abnormal in all patients with signs of optic neuritis and in all but one with a history of optic neuritis. The present results are compared to those obtained in other laboratories and with other types of examinations in MS patients. It is concluded that although the tests are not specific for MS, they give valuable information in the majority of patients with a clinically uncertain diagnosis. This information will most often not be given by other types of examination. The combination of VEP and BAEP is recommended, but it should be supplemented by SEP recording in patients without spinal signs.

Cortical deafness in multiple sclerosis

Cortical deafness in a patient with multiple sclerosis is reported. Complete recovery from total deafness was seen following stages of auditory agnosia and pure word deafness. The otological and neurophysiological studies suggested lesions in subcortical white matter. This report stresses the rarity of the condition, its subcortical origin and good prognosis.

The anatomy and pathology of the central auditory pathways

The anatomy of the central auditory pathways from the cochlear nucleus to the auditory cortex is reviewed. The common pathologies affecting these pathways are described and the neurological, ophthalmological and vestibular symptoms and signs, which are valuable in diagnosing and siting the level of these lesions are discussed.

Hearing loss in brainstem disorders

A retrospective study of 309 unselected patients with brainstem disorders was carried out to establish the incidence and degree of hearing loss in this group as a whole and in each of three separate pathologies: multiple sclerosis, vertebro-basilar ischaemia and brainstem tumours. Pure tone audiograms were corrected for age and sex and upon analysis, thereafter, 59% and 26% of patients were found to have hearing thresholds in excess of 10dB and 30dB respectively. The hearing loss tended to be slight to moderate, 87% of those with a deficit were in the range 11--59dB, and tended to involve the higher frequencies. No characteristic audiometric configuration emerged. 75% of those with a hearing loss suffered a bilateral deficit. Considering the multiple sclerosis, vertebro-basilar insufficiency and tumour groups individually, similar findings were observed with the mildest losses occurring in multiple sclerosis and the most severe in the tumour group.

Multiple sclerosis. The value of clinical vestibular examination

A clinical vestibular examination was carried out on 82 patients with multiple sclerosis (MS) selected on McAlpine's criteria. Spontaneous nystagmus, positional nystagmus or pathological caloric test were found in 49 (60%) patients. Pathological horizontal optokinetic nystagmus occurred in 47 (57%) patients. In 36 cases horizontal optokinetic nystagmus was pathological to both sides, in 28 cases combined with a pathological vertical optokinetic nystagmus, indicative of diffuse intracerebral lesions. Lesions in the central vestibular system and in the optokinetic pathways were frequently discovered in early or atypical cases of MS.