title: Normative studies of the TSEP. The basis of an objective sensory testing procedure in oral and maxillofacial surgery.
abstract: Disturbances of oro-facial sensation may frequently complicate dental surgical procedures, including the extraction of impacted third molars and osteotomies, and are often associated with fractures of the facial bones. The development and refinement of an objective measure of this clinical problem is highly desirable, particularly as it is increasingly being raised as a medico-legal issue. Evoked potential techniques have attracted considerable attention as a means of assessing the function and integrity of nervous pathways. An investigation of the trigeminal somatosensory evoked potential (TSEP) has been undertaken, in the hope of providing a safe, simple objective test of oro-facial sensibility that is acceptable to the patient. The 'normal' TSEP response has been standardised in 23 healthy volunteers, and the typical evoked waveform was found to be in line with the findings of other investigators. The TSEP waveform begins with a positive deflection at 20 ms (P20), followed by a negative deflection at 29 ms (N29) and then a second positive deflection at 37 ms (P37). In all cases, standard stimulation and recording procedures were followed. Stimulation of the maxillary or mandibular branches of the trigeminal nerve at the lip or the gingiva was employed. Evoked potentials were recorded at scalp loci overlying the oro-facial representation area of the post-central gyrus. Averaging and display of data was governed by microcomputer. A standardised method for recording trigeminal evoked responses was satisfactorily achieved and it is suggested that the technique may be useful in the clinical assessment of oro-facial sensory loss.
mesh_terms: D000328:Adult; D004568:Electrodiagnosis / Q000592:standards; D005073:Evoked Potentials, Somatosensory; D005145:Face / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D009055:Mouth / Q000601:surgery; D056948:Orthognathic Surgical Procedures; D014276:Trigeminal Nerve / Q000502:physiology*