Re: nerve conduction studies (NCS) and current perception thresholds (CPT) in workers assessed for hand-arm vibration syndrome (HAVS).

The paper on nerve conduction studies (NCS) and current perception thresholds (CPT) in workers assessed for hand-arm vibration syndrome (HAVS) by Lander et al. [1] while informative contained several oversights about the CPT neurophysiological test that would bias any reader's interpretation of the findings. The standardized automated double-blind CPT evaluation provides a painless objective neuroselective measure of sensory function with a resolution of 620 mAmps at a P , 0.006. Reliable measures may be obtained from individuals receiving potent narcotics [2]. The CPT evaluation measures the functional integrity of unmyelinated and both large and small myelinated sensory nerve fibres that comprise .95% of the typical sensory nerve [3]. The sensory nerve conduction velocity study (NCS) used for comparison to CPT in this study tests only the large myelinated fibres that comprise ,10% of the typical sensory nerve fibres and requires a segment of a large peripheral nerve. Previous CPT studies with HAVS and vibration neuropathy in rats show 100% specificity in the pathology involving myelinated fibres with sparing of the unmyelinated fibres [4–6]. Unfortunately, the authors of the present study overlooked and did not report neuroselective CPT data. Most importantly, the authors conclusion suggesting that NSC is superior because it can detect proximal neuro-pathies such as CTS is missing the fact that the CPT evaluation may be conducted from any cutaneous site as well as mucosal sites. CPT measures are used to evaluate proximal nerve function, focal nerve impairments (including CTS), radiculopathies and myelopathies as well as to distinguish between axonal versus demyelinat-ing polyneuropathies [7–10]. RL. Effects of electrical stimulation at different frequencies on perception and pain in human volunteers: epidural versus intravenous administration of fentanyl. Anesth Analg 1996;82:98–102. 3. Tseng CH. Abnormal current perception thresholds measured by neurometer among residents in blackfoot disease-hyperendemic villages in Taiwan. Acute vibration reduces Ab nerve fiber sensitivity and alters gene expression in the ventral tail nerves of rats. Objective evaluation of sensory function in patients with carpal tunnel syndrome using the current perception threshold. Quantitative analysis of sensory functions after lumbar discectomy using current perception threshold testing. Current perception threshold: an adjunctive test for detection of acquired demyelinating polyneuropathies.