Thermal perception thresholds: assessing the level of human spinal cord injury

Abstract

Controlled, cross-sectional, observational. To investigate whether quantitative sensory testing (QST) is able to reveal subclinical deficits at the neurological level of lesion in subjects with chronic spinal cord injury (SCI). National Spinal Injuries Centre, Stoke Mandeville Hospital and Imperial College London, UK. QST and clinical assessments were carried out on 18 subjects with complete SCI (American Spinal Injury Association (ASIA) grade A) and 10 subjects with incomplete SCI (ASIA grades B, C or D). A total of 10 healthy subjects acted as controls. At the level of lesion perceptual thresholds to monofilaments, cold pain and heat pain were similar to values in control subjects but cool and warm thresholds were significantly raised. A correlation between cool and warm thresholds was observed at the level of lesion in complete SCI and between heat and cold pain thresholds at the level of lesion in complete SCI, incomplete SCI and in control subjects. In the zone of partial preservation in complete SCI and below the level of lesion in incomplete SCI, thresholds for all modalities were all different compared to controls. QST reveals impaired thermal sensation in dermatomes clinically defined as normal with ASIA standards. Quantitative thermal testing therefore permits a discriminating assessment of preserved sensation and subclinical deficit and has the potential to improve upon the clinical detection of natural recovery or changes in level of injury following interventions designed to repair SCI.