Discrepancies between clinical assessments of sensory function and electrical perceptual thresholds after incomplete chronic cervical spinal cord injury

Abstract

Study Design Prospective experimental. Objectives To compare sensory function as revealed by light touch and pin prick tests of the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) and the electrical perceptual threshold (EPT) exams in individuals with chronic incomplete cervical spinal cord injury (SCI). Setting Pittsburgh, United States. Methods EPT was tested using cutaneous electrical stimulation (0.5 ms pulse width, 3 Hz) in 32 healthy controls and in 17 participants with SCI over key points on dermatomes C2 to T4 on each side of the body. Light touch and pin prick ISNCSCI scores were tested at the same key dermatomes in SCI participants. Results In controls, EPT values were higher in older males (1.26±0.2 mA, mean±s.d.) compared with younger males (1.0±0.2 mA) and older females (0.9±0.2 mA), regardless of the dermatome and side tested. Fifteen out of seventeen SCI participants showed that the level of sensory impairment detected by the EPT was below the level detected by the ISNCSCI (mean=4.5±2.4, range 1–9). The frequency distribution of EPTs was similar to older male controls in dermatomes above but not below the ISNCSCI sensory level. The difference between EPT and ISNCSCI sensory level was negatively correlated with the time post injury. Conclusions The results show that, in the chronic stage of cervical SCI, the EPT reveals spared sensory function at lower (~5) spinal segments than the ISNCSCI sensory exam. It is hence found that the EPT is a sensitive tool to assess recovery of sensory function after chronic SCI.

Time-Dependent Discrepancies between Assessments of Sensory Function after Incomplete Cervical Spinal Cord Injury

“…The chronic SCI group was defined based on our previous results highlighting that differences in sensory levels detected by the EPT and ISNCSCI sensory examination followed a similar pattern in persons with SCI up to 10 years post-injury. 9 Because in our previous work, two of the individuals with a SCI for more than 10 years showed different responses, the group with extended-chronic SCI included participants with an injury for more than 10 years. Individuals in the chronic and extended-chronic group were tested at The Miami Project to Cure Paralysis.…”

“…It has been proposed that the electrical perceptual threshold (EPT) examination, which measures the sensory threshold or minimally detectable electrical stimulus intensity applied to the skin, 3 is a sensitive tool to assess sensory function that can complement the ISNCSCI examination after human SCI. [4][5][6][7][8][9] The ISNCSCI and EPT examinations have both been used to assess persons immediately and at well-defined periods after SCI. Using the ISNCSCI, it was found that most sensory and motor recovery occurs within the first months after cervical SCI, [10][11][12] but some sensorimotor recovery was also detected 1-5 years post-SCI.…”

“…13 Interestingly, the EPT detected subclinical changes in sensory function that were not identified by the ISNCSCI examination as early as the first month after SCI 8 and also in persons with a median time of 6.5 years post-SCI. 9 Although understanding the nature and extent of recovery in sensory function in humans with SCI is critical for proper development of clinical studies, rehabilitation therapies, and clinical trials, the extent to which the EPT and ISNCSCI sensory scores change over time after incomplete SCI still remains unknown.…”

“…8 It was recently shown in a group of SCI participants that the EPT examination detected spared sensory function below the ISNCSCI sensory examination in the majority of persons with chronic cervical SCI between 1-10 years post-injury. 9 It has also been proposed that the EPT examination provides a comprehensive assessment of sensory function because EPTs correlate with somatosensory evoked potentials (SSEPs), 14 and by which have a strong prognostic value after SCI. 15 Further, the number of discrepancies reported between light touch and pinprick sensory scores in persons with SCI became larger in those with incomplete SCI.…”

Low Frequencies of Physical Activity in Patients with Spinal Cord Injury

“…PA) must compensate the impairment to maximise the potential for recovery and reduce risks for secondary complications 15,16 . The PA in programs of rehabilitation show positive effects on cardiovascular parameters 17 , motor and sensory functions 18 , psychosocial factors 19 , well-being, functionality 20 , quality of life and everyday activities 11 . The appropriate prescription of exercise programs is needed to improve health status and overall quality of life 3 .…”