Chemli M. Functional hypotonic dysphonia course prediction based on electrophysiological studies

We examined 123 patients with functional hypotonic dysphonia using EEG, SLAEP and LAEP, and divided them into 4 groups according to the violations in the activity of the vocal apparatus observing during videolaryngostroboskopy: 1st - minor disorders in the activity of the vocal apparatus, 2nd - with apparent disorders, 3rd - with complicated disease course, 4th - with complicated disease course and the larynx vestibular hypertonicity. According to SLAEP in all groups of patients with FHD a significant (Р <0,05) increase was observed in the latent period (LPP) of the V SLAEP wave in the groups 2nd, 3rd and 4th, as well as LPP II and III, IPI (interpeak interval) I-V in the 3rd and 4th, moreover - elongation of I-III SLAEP in the 4th group. According to LAEP in all groups of patients with FHD during as 1 as 4 kHz іpsilateral stimulation a significant prolongation of the LPP component N2 LAEP was observed. Also the LPP component P2 was significantly increased in the 3rd and 4th groups of studied patients. Changes were revealed in brain activity in all patients according to EEG, moreover the majority of patients in the 3rd and 4th groups showed the signs of pathology in the diencephalic and stem-diencephalic structures, in percentage of basic rhythms, especially ?-rhythm, with reduction of the ?-rhythm amplitude. It was found that FHD, which goes parallel with progression of disorders in the voice-system in patients, has worsened the functional state of the central parts of the auditory analyzer and brain activity according to AEP and EEG. Obtained data supplement the knowledge of the pathogenesis of vocal dysfunction, the role of the central nervous system functional state and central parts of the auditory analyzer in the origin and development of functional voice disorders