Assessment of Voice and Respiratory Function

Abstract

Voice is multidimensional. Audio recording is the most important basic requisite for voice quality assessment. Once a high-quality complete recording has been attained, it can be stored and remains available. Existing research does not support the complete substitution of instrumental measures for auditory perceptual assessment. To be valuable, however, perceptual assessment should follow a standard procedure, as does the voice recording. A currently used scale for making perceptual judgments is the GRBAS scale. Videolaryngostroboscopy is the main clinical tool for diagnosing the etiology of voice disorders, but it can also be used to assess the quality of vocal fold vibration and thus evaluate the effectiveness of a treatment. The simplest aerodynamic parameter of voicing is the maximum phonation time (MPT), in seconds. It consists of the prolongation of an /a:/ for as long as possible after maximal inspiration and at a spontaneous, comfortable pitch and loudness. A reduction of possible bias (e.g., supportive respiratory capabilities compensating for poor membranous vocal fold closure) is possible by computing the ratio or quotient : Averaged phonation airflow or PQ = VC (ml)/MPT (s). Accu­rate estimation of subglottal pressure can be achieved by measuring the intraoral air pressure produced during the repeated pronunciation of /pVp/ syllables (i.e., a vowel between two ­plosive consonants). Among Voice Range Profile parameters, the highest and lowest frequencies and the softest intensity (decibels, or dBA, at 30 cm) seem most sensitive for changes in voice quality. Although subjective by definition, self-­evaluation is of great importance in clinical practice. Careful quantification is needed for self-evaluation to be compared and correlated with the objective as­­sessment provided by the voice, an important adjuvant technique, laboratory. The Voice Handicap Index is a largely diffused, validated protocol. Electromyography (EMG), an important adjuvant technique, is an electrophysiological investigation of neuromuscular function.