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Quantitative sensory thresholds in carpal tunnel syndrome
M P Merchut1, M A Kelly, S C Toleikis
1Department of Neurology, Loyola University Medical Center.
Electromyography and Clinical Neurophysiology
|February 1, 1990
Summary
Quantitative sensory testing showed limited utility in diagnosing carpal tunnel syndrome (CTS). Electromyography (EMG) is more effective than sensory testing for detecting median nerve abnormalities in mild to moderate CTS.
Area of Science:
- Neurology
- Neurophysiology
Background:
- Carpal tunnel syndrome (CTS) is a common condition causing median nerve compression.
- Accurate diagnosis relies on correlating clinical symptoms with objective testing.
- Quantitative sensory testing (QST) and electromyography (EMG) are diagnostic tools for nerve disorders.
Purpose of the Study:
- To evaluate the diagnostic value of QST for vibration and temperature sensation in patients with confirmed carpal tunnel syndrome.
- To compare QST findings with the severity of median nerve dysfunction indicated by EMG.
Main Methods:
- Vibration and temperature sensation thresholds were measured in the second and fifth digits of 28 hands with symptomatic CTS.
- Thresholds were also measured in 23 age-matched healthy controls.
- Results were correlated with electromyographic nerve conduction study findings.
Main Results:
- Abnormal sensory thresholds, specifically in the second digit, were found in only 11% of CTS hands.
- No significant correlation was observed between sensory threshold abnormalities and the degree of median nerve abnormality on EMG.
- EMG was more sensitive in detecting nerve damage in mild to moderate CTS.
Conclusions:
- QST for vibration and temperature sensation has limited sensitivity for diagnosing carpal tunnel syndrome.
- EMG is a more reliable method for detecting median nerve dysfunction in mild to moderate CTS.
- Focal demyelination in early CTS stages is better identified by EMG than QST.