Measurement of sensory deficiency in fine touch after stroke during textile fabric stimulation by electroencephalography (EEG)

Objective. Sensory deficiency of fine touch limits the restoration of motor functions after stroke, and its evaluation was seldom investigated from a neurological perspective. In this study, we investigated the cortical response measured by electroencephalography (EEG) on the fine touch sensory impairment during textile fabric stimulation after stroke. Approach. Both participants with chronic stroke (n = 12, stroke group) and those unimpaired (n = 15, control group) were recruited. To investigate fine touch during textile fabric stimulations, full brain EEG recordings (64-channel) were used, as well as the touch sensation questionnaires based on the American Association of Textile Chemists and Colorists (AATCC) Evaluation Procedure 5. During the EEG measurement, relative spectral power (RSP) and EEG topography were used to evaluate the neural responses toward the fabric stimuli. In the subjective questionnaire, the fine touch for fabric stimuli was rated and represented by 13 different sensation parameters. The correlation between the fine touch evaluated by the EEG and the questionnaire was also investigated. Main results. The neural responses of individuals with fine touch impairments after stroke were characterized by a shifted power spectrum to a higher frequency band, enlarged sensory cortical areas and higher RSP intensity (P < 0.05). Asymmetric neural responses were obtained when stimulating different upper limbs for both unimpaired participants and stroke participants (P < 0.05). The fine touch sensation of the stroke participants was impaired even in the unaffected limb. However, as a result of different neural processes, the correlation between the EEG and the questionnaire was weak (r < 0.2). Significance. EEG RSP was able to capture the varied cortical responses induced by textile fabric fine touch stimulations related to the fine touch sensory impairment after stroke.