Limb ataxia originating from peri-central sulcus demyelinating lesion in multiple sclerosis

Background: To report the development of limb ataxia/intention tremor (LA/IT) associated with inflammatory demyelinating cortical peri-central sulcus lesions. Methods: We describe a case series of five multiple sclerosis (MS) patients followed at the Jacobs Neurological Institute who developed LA/IT associated with contralateral cortical lesions without visible subtentorial MRI pathology. Demographics, MRI findings and tremor evolution in relation to specific therapies were recorded. Results: Five patients (M = 1/F = 4), age range 29-51 that developed LA/IT associated with a contralateral cortical MRI lesion were identified. LA/IT developed after an average of 3.1 years (range 0-8 years) from disease onset. The contralateral cortical MRI lesion became visible on average 23.2 months before the development of limb ataxia/intention tremor. Central sulcus widening was noted suggesting local atrophy. Median nerve somatosensory evoked potentials revealed asymmetric reductions in N20 amplitudes. Abnormalities in latencies and amplitudes were also noted in the posterior tibial somatosensory evoked potentials, ipsilateral to the lesion. Symptomatic therapeutic interventions were only partially beneficial. Conclusion: Limb ataxia/intention tremor can be associated with a demyelinating lesion involving cortical and adjacent subcortical white matter, in the absence of rubro-cerebellar lesions. Aggressive therapeutic intervention to control the cortical inflammatory process is recommended.