INFLUENCE OF TACTILE AND PROPRIOCEPTIVE SENSORY STIMULATION ON THE CEREBRAL CORTEX: SUPPLEMENTARY MOTOR AREA (SMA)

I. Sanz Esteban¹, C. Estrada Barranco¹, P. Rico¹, C. Jimenez Antona², R. Cano De La Cuerda², J.I. Serrano³

¹Universidad Europea de Madrid, Physical Therapy, Faculty of Sport Sciences, Madrid, Spain, ²Universidad Rey Juan Carlos, Physical Therapy, Occupational Therapy, Physical Medicine and Rehabilitation, Madrid, Spain, ³Superior Council of Scientific Investigations (SCSI), Center for Automation and Robotics of the SCSI, Madrid, Spain

Background: The main therapeutic tool of the physiotherapist is his hands. The precision of the sensory stimulus transmitted by the physiotherapist's hands is essential for the brain to register it properly and respond in the best possible way.
Patients with neurological disorders usually have difficulties at the sensorimotor level. Being able to know and show through EEG the existence of activation in the areas that prepare and organize movement before a specific and defined tactile and proprioceptive stimulus allows us to establish a promising line of work that helps to know how the CNS responses to tactile sensory stimuli favor neuroplasticity.

Purpose: Increase knowledge of the main motor or premotor areas of the cerebral cortex that are active during the application of a specific tactile and proprioceptive sensory stimulus.
Analyze the responses of the supplementary motor area.

Methods: A randomized-controlled trial was conducted. Participants were randomly distributed into two groups: a non-specific tactile input-group (non-STI-group) (n = 20) and a Vojta specific tactile input-group (V-STI-group) (n = 20). The non-STI-group was stimulated in a non specific area (quadriceps distal area) and V-STI-group was stimulated in a specific area (intercostal space, at the mammillary line between the 7th and 8th ribs) according to the Vojta therapy. Recording was performed with EEG for 10 min considering a first minute of rest, 8 min during the stimulus and 1 min after the stimulus. EEG activity was recorded from 32 positions with active Ag/AgCl scalp electrodes following the 10–20 system. The continuous EEG signal was split into consecutive segments of one minute.

Results: The V-STI-group showed statistically significant differences in theta, low alpha and high alpha bands, bilaterally in the supplementary motor (SMA) and premotor (PMA) areas (BA6 and BA8), superior parietal cortex (BA5, BA7) and the posterior cingulate cortex (BA23, BA31). For the V-STI-group, all frequency bands presented an initial bilateral activation of the superior and medial SMA (BA6). This activation was maintained until the fourth minute. It is remarkable the great activation that occurs in the ipsilateral (SMA) of the stimulus from minute five and six, the activation in the upper and middle SMA rose again in the three frequency bands.

Conclusions: Our findings highlight that the specific stimulation area at intercostal space, on the mammillary line between 7 and 8th ribs according to Vojta therapy differentially increased bilateral activation in SMA (BA6) and Pre-SMA (BA8), BA5, BA7, BA23 and BA31 in theta, low and high alpha bands in healthy subjects. These results could indicate the activation of innate locomotor circuits during stimulation.

Implications: Knowledge of the activation of areas involved in the organization and motor programming that are activated at the brain level (SMA) during the performance of an adequate and specific tactile sensory stimulus. Specifically, knowing how often and for how long these SMA zones are activated before the application of the sensory stimulus, can help to establish the bases on the suitability of the application of manual stimuli to help in the activation of the premotor zones in those patients who they need it.

Funding acknowledgements: The authors would like to thank the volunteers for participating in this study.
Funding not applicable

Keywords:
Brain activity, cortical activity
Electroencephalography
Tactile stimulation, Vojta therapy

Topics:
Neurology
Disability & rehabilitation

Did this work require ethics approval? Yes

Institution: Rey Juan Carlos University

Committee: Comité Etica URJC

Ethics number: 2309201912919