The Use of Visual Feedback in Establishing Normal Vocal Intensity in Two Mildly Retarded Adults

Abstract

A voice-activated relay was used to provide visual feedback of vocal amplitude for two subjects who habitually used very soft voices. The relay system caused a light to go on when vocal intensity was 65 dB SPL or greater. Both subjects demonstrated significant increases in their use of normal vocal intensity. One subject was able to transfer this progress to spontaneous conversational settings. Though some difficulties in generalization and automatization were evident, this system is recommended for use with persons exhibiting functional intensity deficiences.

Effects of Biofeedback in Phonatory Disorders and Phonatory Performance: A Systematic Literature Review

“…As shown in Table II, only five studies (29.4%) mentioned long-term results. Whereas Andrews et al (1986), D'Antonio et al (1987 and Sime and Healey (1993) reported retention after respectively 3, 1 and 15 months, there was no longterm effect of biofeedback after 5 months (Brody et al, 1975), or, in one case, even in the second baseline period directly after biofeedback therapy (Till et al, 1987). Several advantages can be enumerated.…”

“…The biofeedback therapy in the participant described by Sime and Healey (1993) maintained the decreased laryngeal EMG levels at the 15-months follow-up. On the other hand, the two patients described in Brody et al (1975) showed no retention of the effects of biofeedback therapy after 5 months. Till et al (1987) reported that the therapeutic effect demonstrated in that study disappeared once the biofeedback stopped.…”

“…A third challenge lies in direct rather than analogue evidence voice quality. Instead of working with quantitative measurements-as for example, Brody et al (1975), Holbrook et al (1974), Howard and Welch (1989), Till et al (1987), and others-this might be best achieved through the use of real-time continuous display of a voice quality-related parameter.…”

“…This means that there is no discrepancy with the goal for which it was used, since microphones are developed for acoustic waveform measurements (intensity and pitch). Microphones (and the real-time feedback on acoustical properties) seem to be effective in decreasing abusive vocal intensity (Holbrook et al, 1974;McGillivray et al, 1994), increasing hypofunctional intensity (Brody et al, 1975), increasing vocal performance (Howard & Welch, 1989;Rossiter et al, 1996) and reducing stomal noise (Till et al, 1987), but seems unable to increase overtones (Laukkanen et al, 2004).…”

“…Only three patients (11.1%) were not helped by the treatment and underwent microlaryngoscopy and vocal cord stripping. Brody, Nelson, and Brody (1975) described two case studies with a multiple measurement design (without baseline). Both participants were adults with mild mental retardation, diagnosed with hypofunctional dysphonia.…”