A new electrophysiological method for assessing somatosensorial stimulations in physiotherapy

The aim of this study was to investigate the brain oscillatory responses to tactilestimuli (somatosensory evoked oscillations) in healthy adults by comparing the resultswith visual and auditory evoked oscillations. 60 young adults with ages ranging from 18-29 volunteered to this study. They were randomly divided into three groups:somatosensory, visual and auditory and received one of these sensory stimulusrespectively. The tactile stimulus was given means a pneumatic stimulator. Each volunteerwas seated in a electromagnetically- and soundproof and dimly illuminated room. Surfaceelectrodes were placed according to the international 10-20 system andelectroencephalographic (EEG) recordings were made. The subject received 60 stimuliwith a random interstimulus interval in one session. After artefarct rejection, maksimumamplitudes 1000 ms poststimulus of filtered EEG recordings were statistically analysedwith ANOVA. Our results show that tactile stimulation to the index finger show an overallsignificant delta response (0,5-3,5 Hz) and different from auditory and visual evokedoscillations, alpha (8-13 Hz) and teta (4-7 Hz) responses over primary and secondarysensory cortices. All three sensory modalities evoked an overall beta (15-30 Hz) andgamma (28-48 Hz) response in the human cortex. We conclude that especially slowrhythms are sensory modality specific brain oscillations which may serve as a tool inrehabilitation research in the future.Keywords: somatosensory evoked potentials, brain oscillations, ERO, tactile, pneumaticstimulation,2