Peripheral sensory abnormalities in patients with multiple sclerosis

Abstract

Although multiple sclerosis primarily affects myelin within the central nervous system, both pathologic and physiological studies suggest that mild deficits in peripheral nervous system myelin may be common. To evaluate this question further, we performed near nerve studies on sural nerves of 14 patients with multiple sclerosis. Peak-to-peak amplitude and maximum conduction velocity were normal in 9 of 14 patients, while minimum conduction velocity, or the velocity of the slowest-conducting component of the sensory action potential, was abnormally reduced in 9 patients. In addition, the supernormal period was evaluated for patients and compared with a control sample; multiple sclerosis patients showed a significant reduction in the amplitude of supernormality. Both the reduction in minimum conduction velocity and the alteration in the supernormal period are consistent with a mild defect in peripheral myelin.

Chronic Inflammatory Demyelinating Polyradiculoneuropathy Associated With Multiple Sclerosis

“…No distinction between demyelinating and axonal PNS involvement was made. Moreover, the extent of CNS and PNS involvement varied greatly, ranging from subclinical to clinically evident disease 4,5 as judged from the reported electrophysiologic, [21][22][23][24][25][26][27][28] neuroimaging, 9,[28][29][30] and pathologic [31][32][33][34] abnormalities.…”

Cardiac autonomic function during sleep in several neuropsychiatric disorders

“…Another possibility is that the damage of peripheral afferent or efferent pathways may contribute to ANS impairment. Consistent abnormalities in peripheral sensory nerve conduction have been demonstrated in MS, probably asa result of a defect in the myelin of the peripheral nervous system [24].…”

Central motor drive is increased during voluntary muscle contractions in multiple sclerosis

“…This feature is reflected in the similar group MVC and CMAP amplitudes. Though these measures are not definitive, it is thus unlikely that muscle atrophy or lower motor neuron dysfunction, as sometimes observed in persons with MS, 29 could have substantially influenced our results.…”

“…These data were subsequently transferred to a spread sheet, rectified, and integrated. To rule out any peripheral changes in motor nerve excitability that might affect the surface EMG, 29 the compound muscle action potential (CMAP) in response to a single supramaximal stimulus of the peroneal nerve was obtained as previously described. 17 Three CMAPs were collected 1 min apart at a sampling rate of 2500 Hz for 0.5 s and reported as peak to peak amplitude.…”