Heat sensitivity of sensory fibers in carpal tunnel syndrome

• Published in: Muscle & nerve 1999-01, Vol.22 (1), p.37-42
• Main Authors: Wang, Annabel K., Raynor, Elizabeth M., Blum, Andrew S., Rutkove, Seward B.
• Format: Article
• Language: English
• Subjects: Adult; Age Factors; Aged; carpal tunnel syndrome; Carpal Tunnel Syndrome - physiopathology; compression; conduction block; demyelination; Female; heat; Hot Temperature; Humans; Linear Models; Male; Middle Aged; Neural Conduction - physiology; Neurons, Afferent - physiology
• ISSN: 0148-639X; 1097-4598
• DOI: 10.1002/(SICI)1097-4598(199901)22:1<37::AID-MUS7>3.0.CO;2-G

Elevations in temperature may produce conduction block in demyelinated neurons. A well‐described phenomenon in multiple sclerosis, it has also been reported in some patients with inflammatory demyelinating polyneuropathies. We used carpal tunnel syndrome (CTS) as a model to study the effect of heat on nerves with focal demyelination secondary to chronic compression. Compound motor and sensory responses were measured in 12 CTS patients and 12 normal subjects at 32°C and with heating to 42°C. Changes in relative motor response amplitude and area were similar for both normal subjects and CTS patients. In CTS patients, however, sensory response amplitude and area decreased 34.3% and 48.9%, significantly more than the 25.2% and 39.1% reductions in normal subjects (P = 0.021 and P = 0.018 respectively). We hypothesize that these reductions in response amplitude are secondary to the occurrence of heat‐induced conduction block in demyelinated sensory neurons. © 1999 John Wiley & Sons, Inc. Muscle Nerve 22: 37–42, 1999