The risk assessment framework for hyperfunctional voice disorders

Abstract

A number of risks have been proposed in the literature to be associated with hyperfunctional voice disorder (HVD), one of the most common communication disorders. Yet, it is not distributed randomly in the population, certain population groups are at higher risks of developing voice disorders. It is generally agreed that the development of voice disorders involves a multifactorial genesis. The study of risks has been documented in different diseases and also in the World Health Report (W.H.O., 2002). The probabilistic approach has been recommended to effectively manage the likelihood of health outcome in relations to disease development (Tonetti, 1988) and systematically devise prevention and intervention programs targeting population at risk. Yet, in the study of the development of HVD, the lack of a universally agreed theoretical framework prohibited the establishment of such structure and research on advancement on preventive programs.

The present thesis aimed to investigate the adoption of the FMAT risk assessment framework based on the probabilistic approach (WHO) to the field of hyperfunctional voice disorders. A Voice Risk Calculator (VRC) Questionnaire was developed focusing on the vocal loading, physiological/medical and psycho-emotional indicators and all subjects completed this questionnaire. The VRC Questionnaire was then validated based on the FMAT framework using a cross-sectional study was used to identify risk indicators associated with HVD development in the local population and a longitudinal study was employed to validate these risk indicators as risk factors. A total of 192 Cantonese-speaking subjects participated in the cross-sectional study including 123 dysphonic subjects and 69 non-dysphonic control subjects and 7 in the longitudinal study. Instrumental measurements including the voice range profile, aerodynamic measurements and the Voice Activity and Participation Profile (VAPP, Ma & Yiu, 2001) were also used as part of the validation procedure.

The findings showed that significant differences were found between the dysphonic and non-dysphonic group in the cross-sectional study based on results from the instrumental measurements protocol. A minimal set of selected VRC questionnaire items were also determined (Items 1, 3, 25 and somatization scale) to differences between the subject groups in this study. Thus a set of locally-applicable risk indicators have been suggested. Yet, only minimal changes have been detected in a high-risk group targeted in the longitudinal study. Research (Beck, 1994) indicated that disease progression takes over a time frame of at least more than two years. Thus the small subject size and temporal element of the longitudinal study in the present thesis limited research aim to be achieved. Nonetheless that first phase of the FMAT framework for hyperfunctional voice disorders have been established in the current study and a finalized version of the Voice Risk Calculated Questionnaire has been developed for future research.