Observed changes in clinical proxy measures of airway protection after cervical epidural spinal cord stimulation in neurological disorders: a preliminary retrospective case series.

OBJECTIVES: Although spinal cord stimulation (SCS) has been investigated for cough and respiratory motor output after neurological injury, its relationship with clinical proxy measures of airway protection remains unclear. We explored observed changes in aspects of airway protection after cervical SCS in patients with neurological disorders. MATERIALS AND METHODS: We retrospectively analyzed six patients who underwent cervical SCS for spinal cord injury, amyotrophic lateral sclerosis, or disorders of consciousness. Clinical proxy measures included the Semi-quantitative Cough Strength Score (SCSS), Functional Oral Intake Scale (FOIS), Water Swallow Test (WST), and Chinese Swallowing Quality of Life Questionnaire (cSWAL-QoL). SCSS was available for all six patients, whereas FOIS, WST, and cSWAL-QoL were limited to the four conscious patients. SCSS, FOIS, and WST were descriptively compared across preoperative, stimulation ON, and stimulation OFF conditions when clinically permissible. cSWAL-QoL was compared between preoperative and postoperative follow-up. RESULTS: During active stimulation, SCSS scores were higher in all six patients, with the median score changing from 3.0 preoperatively to 4.0 during stimulation ON (nominal p = 0.031). SCSS was also higher during stimulation ON than OFF (4.0 vs. 3.0; nominal p = 0.031). Among the four conscious patients, FOIS changed from 4.0 to 5.0 and WST changed from 3.5 to 2.5 during stimulation ON, while cSWAL-QoL changed from 91.0 to 151.5 postoperatively. No stimulation-related adverse events occurred. CONCLUSION: Clinical proxy measures related to airway protection showed exploratory state-associated changes during cervical epidural SCS, particularly in cough-strength scores. These preliminary findings do not establish efficacy or mechanism.