The influence of inhaled corticosteroids on normal voice production in adults : an acoustic study
Thesis DisciplineHealth Sciences
Degree GrantorUniversity of Canterbury
Degree NameMaster of Health Sciences
Corticosteroids are the most potent and reliable of the available agents among the anti-inflammatory drugs, and have assumed a major role in the management of asthma. This has subsequently resulted in the global widespread use of inhaled corticosteroids (ICS). A variety of studies have been undertaken to examine the effects of ICS on voice production among people with asthma. Most research suggests that the long-term use of ICS has a negative effect on voice production. However, the results of these studies are limited because of the reliance upon examining an asthmatic population and not consistently recording the dose prescribed. As a result, one cannot exclude that some of the voice problems may have been previously caused by asthma and thus, the contributing effects of ICS are obscured. Therefore, an ideal approach to examine the influence of ICS on voice is to test its short-term effects on healthy individuals, using a specific ICS (Fluticasone Propionate) at a fixed dose (1000 µg/Day). Thirty healthy adults (15 females & 15 males) aged between 18 to 30 years participated in this study. All participants were non-smokers with no history of speech, language or voice disorder. No participants had a history of asthma, respiratory illness hospital admission or inhaler use within the past 3 months. All participants followed the treatment regime often prescribed by physicians (in Canterbury region) for treating asthma (500 µg in morning & 500 µg in evening). Each participant self administered (inhaled) two puffs of ICS in the morning and again in the evening over a six day period. Voice samples were audio-recorded prior to undergoing the ICS regime, at various points during the ICS regime, and at the conclusion of ICS regime. Each participant’s audio-recorded samples were submitted for acoustic analysis using a commercially available speech analysis system (CSL 4300B, Kay Elemetrics, 1994). Three measures were performed, (1) vocal fundamental frequency (F0), (2) long-time spectral analysis (LTAS) and (3) formant frequency and formant frequency bandwidth. The results of this study indicate that ICS does have an effect on acoustic properties of voice. These effects were more evident in connected speech compared to isolated vowel productions. In particular, the spectral tilt and first spectral peak of continuous speech samples were found to change from baseline. The current results are discussed in regard to the phonatory deterioration associated with ICS use. The present study provides a framework for developing ICS treatment for respiratory disease in the phase of minimizing adverse effects on voice.