Changes in electrical perceptual threshold in the first 6 months following spinal cord injury

Abstract

Objectives: To investigate the use of electrical perceptual threshold (EPT) testing to follow the natural history of sensory progression after complete and incomplete acute spinal cord injury (SCI) and to compare EPT changes with the American Spinal Injuries Association (ASIA) Impairment Scale (AIS). Study Design: Prospective descriptive study. Methods: ASIA examination and EPT testing was performed on 17 patients (7 AIS A, 10 AIS B-D), within 1, 3, and 6 months after acute SCI. EPT assessment was carried out bilaterally at ASIA sensory points from 2 levels above the neurological level to all levels below, including the sacral segments. Comparisons of EPT values above, at, and below the SCI were made at the three time points as well as comparisons of EPT data to ASIA assessment. Results: There was poor agreement between lowest normal level on EPT and ASIA assessment. Over time, EPTs tended to deteriorate above and at the ASIA level in AIS A patients with modest changes below the neurological level of injury (NLI), mainly where EPTs correlated with the zone of partial preservation. Sacral sparing was detected in one patient with EPT testing, but not with ASIA assessment. AIS B-D patients showed improvement at the ASIA level and extensive changes, both improvement and deterioration, below the NLI. Conclusion: EPT testing has sufficient sensitivity to detect subclinical changes in sensory function as early as the first month post-SCI, which is not apparent in ASIA examination. In particular, the testing is able to show abnormalities at and around the injury site for both complete and incomplete SCI. In addition, EPT allows for the detection and monitoring of alterations, both improvements and deterioration, in the abnormal range of sensation.

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

“…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.…”

“…For example, a study comparing the pinprick and light touch sensory sections of the ISNCSCI examination with the EPT in humans with incomplete SCI revealed that the number of participants with a sensory level detected by EPT above the level assessed by the ISNCSCI examination was larger *1 month compared with later months after injury. 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.…”

“…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.…”

Development and validation of a bowel-routine-based self-report questionnaire for sacral sparing after spinal cord injury

“…3 Thus, it is important to promptly detect any improvement or deterioration of the neurological impairment 4,5 or any possible effects of clinical care both in the acute phase after injury and during the long-term follow up. 5,6 Besides, monitoring the neurological level of injury and the AIS grade will also support clinical research and provide better understanding regarding the pathophysiology following SCI. 6 Among the evaluations to be performed when classifying SCI using the ISNCSCI, sacral sparing is the most important component to distinguish a complete injury (AIS A) from an incomplete one (AIS B/C/D), as well as a sensory incomplete injury (AIS B) from a motor incomplete one (AIS C/D).…”

“…5,6 Besides, monitoring the neurological level of injury and the AIS grade will also support clinical research and provide better understanding regarding the pathophysiology following SCI. 6 Among the evaluations to be performed when classifying SCI using the ISNCSCI, sacral sparing is the most important component to distinguish a complete injury (AIS A) from an incomplete one (AIS B/C/D), as well as a sensory incomplete injury (AIS B) from a motor incomplete one (AIS C/D). 1 The definition of sacral sparing was first introduced as a criterion of classification in the 1992 revision of ISNCSCI.…”