Age and upper limb tension testing affects current perception thresholds.

Current perception threshold (CPT) testing was used to quantitatively measure the sensory response to upper limb tension testing (ULTT). The study addressed the ability of ULTT to tension the intended nerve, and the influence of age on CPT. Normal subjects (n=59) performed a randomized series of CPT tests at 5 and 2,000 Hz in a resting position and in a median-nerve bias position using the Neurometer. Results indicate that ULTT impacts CPT in normal subjects, with greater effects observed in the ulnar nerve (p<0.05) than for median nerve (NS). Age was a significant covariate for CPT (2,000 Hz, p=0.032; 5 Hz, p=0.034), and Pearson correlations indicated a weak but significant correlation of age with CPT. Age had a differential impact on CPT frequencies, suggesting differential impacts on nerve fibers, with a trend towards hypoesthesia at 2,000 Hz (r=0.10 to 0.30) and toward hyperesthesia at 5 Hz (r=-0.16 to -0.28). ULTT causes measurable effects in the sensory threshold of peripheral nerve, which are more pronounced with age; increased touch threshold and decreased pain thresholds can be expected. The specificity of nerve bias elicited by specific ULTT needs further exploration.