Cutaneous silent period recordings in demyelinating and axonal polyneuropathies

Reversible cutaneous silent period abnormalities in vitamin B12 deficiency: A case report

“…Observed CSP abnormalities in the present patient, i.e. delayed onset but normal duration, is actually in agreement with demyelination of A-delta fibers (Lopergolo et al, 2015), while incomplete EMG suppression rather suggests profound axonal loss of A-delta fibers. The fact that CSP abnormalities returned to entirely normal values after 21 months of intramuscular vitamin B12 substitution also concurs with demyelination and secondary remyelination (Fine and Soria, 1991, Kalita et al, 2014), which tends to recover better than axonal loss.…”

A neurophysiological study of large- and small-diameter nerve fibers in the hands of hemodialysis patients

“…In addition, increasing motor neuron firing in axonal polyneuropathy may influence CSP parameters producing shorter CSP duration. CSP onset latency delay is considered a problem with conduction properties of A-delta nerve fibers [38]. The finding of prolonged CSP duration in axonal and demyelinating polyneuropathies is supported by previous nerve biopsy studies, which showed loss of both large-and small-diameter nerve fibers in patients with diabetic polyneuropathy [39].…”

“…It is known that cold sensation is mediated by thin myelinated A-delta nerve fibers, and the authors suggested that thin myelinated A-delta nerve fibers are more affected than unmyelinated fibers in UP. The authors did not find significant CSP parameter alterations between patients with and without pain, excluding C-nerve fiber involvement [38]. The advantage of CSP is that it is simple and can be conducted in most laboratories.…”

The utility of electrodiagnostic tests for the assessment of medically unexplained weakness and sensory deficit

“…If in doubt, the use of an oscilloscope sweep-triggering hammer may be of interest to obtain the latency of the muscle response to the tendon tap (Péréon et al, 2004). In limb muscles, the presence of a normal silent period to electrical stimulation indicates normal afferent inputs not only for large fibers but also for small fibers (Kofler, 2003, Lopergolo et al, 2015). Cutaneous reflexes such as the long latency reflexes of hand muscles (Deuschl and Lücking, 1990, Chen and Ashby, 1993) may also be useful to disclose absence of damage in the segments of the sensory system involved in the reflex.…”