Hypoaesthesia occurs with sensory hypersensitivity in chronic whiplash - Further evidence of a neuropathic condition

Abstract

Hypersensitivity to a variety of stimuli has been shown in whiplash associated disorders and may be indicative of peripheral nerve involvement. This cross-sectional study utilised Quantitative sensory testing (QST) including vibration, thermal, electrical detection thresholds as an indirect measure of primary afferents that mediate innocuous and painful sensation. Pain thresholds and psychological distress (SCL-90-R) were also measured. Thirty-one subjects with chronic whiplash (>3 months, NDI: 49+/-17) and 31 controls participated. The whiplash group demonstrated elevated vibration, heat and electrical detection thresholds at most hand sites compared to controls (p<0.05). Electrical detection thresholds in the lower limb were no different from controls (p=0.83). Mechanical and cold pain thresholds were lower in the whiplash group (p<0.05) with no group difference in heat pain thresholds (p>0.1). SCL-90 scores were higher in the whiplash group but did not impact on any of the sensory measures. A combination of pain threshold and detection measures best predicted the whiplash group. Sensory hypoaesthesia and hypersensitivity co-exist in the chronic whiplash condition. These findings may indicate peripheral afferent nerve fibre involvement but could be a further manifestation of disordered central pain processing.