Electrophysiological findings in the syndrome of acute ocular muscle palsy with ataxia (fisher syndrome)

Abstract

4 patients are described with ophthalmoplegia (Figs. 1 and 2) and ataxia with acute onset. Three of them showed only very slight symptoms of generalized polyneuritis. Measurement of sensory nerve conduction velocity (Fig. 4, Table 2) and determination of vibration sense by an electrical vibrator (Fig. 3) proved to be helpful for diagnosis. The ocular EMG revealed signs of peripheral denervation in 3 cases. Pathological changes of the somatosensory evoked potential (Fig. 5) which has been registered in one case, might give some speculation as to whether or not central nervous pathways are affected.

Miller Fisher Syndrome: A Hospital-Based Retrospective Study

“…These findings suggest a block of conduction in the spinal roots, limb girdle plexuses or proximal segments of the nerves. Several reports had the consensus that sensory changes predominated with significant loss of amplitudes and mild motor and sensory conduction slowing [21, 22, 25, 26, 29]. In our study, this phenomenon was not observed.…”

“…As the result reported by Shuaib and Becker [19], all of the antecedent events in our patients were URTI only. Gastrointestinal infection, which was the second common one reported by other series [20, 21], was not present in our patients. In contrast to the previous report [18], the commonest initial symptom in our patients was dizziness (6/11, 54.5%) rather than diplopia (table 2).…”

“…Some investigators regard it purely as brainstem encephalitis based on ocular findings and cerebellar ataxia [8, 9, 21, 49, 50]. Many of the ocular motor signs, such as symmetrical ophthalmoplegia, Parinaud’s syndrome, convergence spasm, preserved Bell’s phenomenon despite upward paresis and internuclear ophthalmoplegia have been considered to be due to central nervous system lesions.…”

“…The results have been controversial. Although some studies revealed no evidence of affection of the peripheral nerves [9, 11, 12, 13], most studies revealed peripheral nerve involvement such as abnormalities in distal motor latencies, motor conduction velocities, sensory conduction velocities, F wave latencies and H reflexes [19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34]. Three out of our 10 patients had abnormal electrophysiological findings.…”

Demyelinating Features in Sensory Nerve Conduction in Fisher Syndrome

“…The days listed in the nerve conduction studies (NCSs) column indicate the timing of the NCSs from the onset of FS. Abbreviations: URI: upper respiratory infection case series indicate that demyelinating processes cause the decreased amplitudes of SNAPs observed in patients with FS (11)(12)(13)(14), whereas the results from two large case series suggest that axonal neuropathy or dorsal root ganglionopathy are responsible (8,10). Therefore, the question of whether decreases in SNAP amplitudes result from a demyelinating process or an axonal mechanism remains controversial.…”