Spinal cord injury results in restricted somatosensory input to the central nervous system. Evidence from experimental and human sensory deprivation literature suggests that loss of such input could influence both cortical arousal and subsequent cognitive efficiency. To test that hypothesis, spinal cord injured individuals and able-bodied controls were asked to perform an auditory vigilance task which, by its nature, should enhance spinal cord injured/able-bodied differences. There were no differences between the inpatient paraplegic, quadriplegic, or the able-bodied persons on measures of arousal or task efficiency. However, recently injured spinal cord patients showed lower arousal and decreased task efficiency compared to spinal cord injured subjects with older injuries or the able-bodied. There was also an effect noted for hospitalization. Outpatient quadriplegic individuals who had been injured for a long time performed better on the vigilance task than spinal cord injuries inpatients and able-bodied control groups. Results are discussed in terms of sensory deprivation theory and relevance.