We read with great interest the article by Wolfe and colleagues1 on chronic cryptogenic sensory polyneuropathy (CSPN) and their conclusion on the clinical and laboratory characteristics of the disease. The authors provided an extensive overview on their large series of patients with CSPN. However, we have some questions about the criteria recommended to define the diagnosis. Sensory symptoms were mandatory, and minimal weakness or atrophy in muscle supplying toes and fingers was allowable, while patients with symptoms of weakness were excluded. Tendon hyporeflexia was not mandatory. Nerve conduction studies should show the predominant impairment of sensory fibers, but motor involvement was also allowed. The authors identified 93 patients who had positive and/or negative sensory disturbances and met the diagnostic criteria for CSPN. Consistent with the proposed criteria, no one complained of motor symptoms, although 41% showed distal weakness and 15% had muscle atrophy of lower or even upper extremities. Results of electrodiagnostic studies revealed decreased compound muscle action potential (CMAP) amplitude and motor conduction velocity in the lower extremities in more than 50% of patients and in the upper extremities in about 8% of patients. Surprisingly, increased ulnar motor distal latency and decreased conduction velocity were found in 20.8% and 8.3% of cases, respectively. Similarly, the median motor distal latency was abnormal in 17.6% of patients and conduction velocity was impaired in 20.3% of cases. Results of electromyography were abnormal in 70% of patients.
Lauria G, Pareyson D, Sghirlanzoni A. Chronic Cryptogenic Sensory Polyneuropathy. Arch Neurol. 2000;57(5):759-760. doi: