Implementation of the European Laryngological Society (ELS) basic protocol for assessing voice treatment effect

93 patients with various kinds of organic benign voice pathology (vocal fold nodules, polyp, Reinke's oedema, unilateral paralysis, sulcus/scar) and/or with muscle tension dysphonia, were evaluated before and after their voice treatment (phonosurgery with voice therapy, antireflux medication, or voice therapy alone) in order to check the clinical relevance of a basic multidimensional protocol for assessing functional results of voice treatments, as developed by the Committee on Phoniatrics of the ELS.

The protocol has been used in different university voice clinics. It comprises 5 dimensions: Perception: Grade, Breathiness and Roughness from the GRBAS-scale, rated by two experienced judges: a phoniatrician/laryngologist and a speech therapist. Acoustics: Jitter % and Shimmer % computed on a /a:/, at comfortable loudness and pitch. Also Fo-range and softest possible intensity. Videostroboscopy: Glottal closure, regularity, mucosal wave and symmetry, rated separately. Phonation quotient: computed by dividing the vital capacity (ml) by the maximum phonation time (s) (best value of 2x3 trials). Self rating by the patient: voice quality in itself and general social/occupational handicap due to the voice problem rated separately.

Results show that, at group level, the overall effects for each parameter indicate a significant improvement after treatment. However, the correlations between the pre/post changes for the different parameters are weak (low redundancy).

The assessment of voice pathology needs to be multidimensional, as these multidimensional informations about voice changes lead to a better understanding of the actual way in which a treatment works.