Tactile Sensitivity of the Oral Tissues and Chewing Efficiency Are Impaired in Stroke Patients

Material and Methods:

Ethical approval was granted (Psy11-259, Psy 11-032) and written informed consent was obtained from all participants and/or their legal guardian. Patients were screened and recruited from the Division of Neurorehabilitation, Department of Clinical Neurosciences, University Hospital and University of Geneva, Geneva, Switzerland by a senior consultant neurologist (BL). Patients were included if they were hospitalized for stroke rehabilitation, were able to undergo psychophysical testing and presented with a facial impairment according to the House-Brackmann criteria ≥2 15. They were excluded if they presented with acute pain in the oro-facial sphere (nominal question) or an additional neuro-muscular disease.

For the experiments, an in-depth oral examination was performed and the number of functional premolar units (OU) was noted. A premolar tooth with occluding antagonist counts as one OU whereas a molar is considered two OU (including third molars). Participants were asked with a simple dichotomic question if they perceived a dry mouth.

Food-hoarding Food-hoarding was assessed with an ordinal Likert scale. Participants were asked if they currently "lost" foodstuff in the oral vestibule: Never (score 0), rarely (score1), occasionally (score2), frequently (score 3), very frequently (score 4) or always (score 5).

Maximum voluntary bite force Maximum voluntary Bite Force (MBF) was assessed by means of an Occlusal Force-Meter GM 10® (Nagano Keiki, Higashimagome, Ohta-ku, Tokyo, Japan), which has an 8.6 mm thick bite element. The gauge was placed in-between the first molars and the participants were asked to bite three times as hard as possible for about three seconds. The MBF was tested independently on the right and left side. For the analysis, the peak MBF of each side was noted.