The effect of different physiological stimuli on skin vasomotor reflexes above and below the lesion in human chronic spinal cord injury.
OBJECTIVE
Spinal cord injury (SCI) results in disruption of descending tonic activation of sympathetic circuits in the spinal cord. The authors determined whether different stimuli that increase sympathetic activity induced cutaneous vasoconstriction (skin vasomotor reflex, SkVR) above and below the level of lesion in subjects with clinically complete SCI.


METHODS
Baseline skin blood flow (SkBF) and SkVR reduction rate in the pulp of the finger and great toe was measured by laser Doppler probes in chronic complete SCI and in controls.


RESULTS
In the finger, baseline SkBF was similar in SCI and controls. The SkVR was elicited by all stimuli in controls but was significantly diminished to gasp, mental arithmetic, tactile stimulation, cutaneous cold, and deep breathing in high SCI compared to controls. In the toe, baseline SkBF was less stable in both controls and SCI. SkVR trends were identified in controls, and responses were not present or greatly reduced in high and low SCI.


CONCLUSIONS
Measurements of skin vasomotor reflexes to physiological stimuli may be a noninvasive method to evaluate the extent of sympathetic adrenergic pathways in chronic SCI. This is of clinical relevance in monitoring recovery of sympathetic adrenergic function either spontaneously or following repair interventions.
Nicotra
Alessia
A
Neurovascular Medicine Unit, Faculty of Medicine, Imperial College London at St Mary's Hospital, UK. a.nicotra@imperial.ac.uk
Young
Tim M
TM
Asahina
Masato
M
Mathias
Christopher J
CJ
D000328:Adult; D016022:Case-Control Studies; D002574:Cervical Vertebrae; D005260:Female; D005385:Fingers / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010812:Physical Stimulation; D012021:Reflex, Abnormal / Q000502:physiology*; D012653:Self Stimulation; D012867:Skin / Q000503:physiopathology*; D013119:Spinal Cord Injuries / Q000503:physiopathology* / Q000523:psychology; D013904:Thoracic Vertebrae; D014034:Toes / Q000503:physiopathology; D014666:Vasomotor System / Q000503:physiopathology*