Phonation stabilisation time as an indicator of voice disorder

Abstract

There is increasing emphasis on use of connected speech for acoustic analysis of voice disorder, but the differential impact of disorder on initiation, maintenance and termination of phonation has received little attention. This study introduces a new measure of dynamic changes at onset of phonation during connected speech, phonation stabilisation time (PST), and compares this measure with conventional analysis of sustained vowels. Voice samples obtained from the KayPENTAX Disordered Voice Database were analysed (202 females, 128 males) including 'below threshold' voices where there was a clinical diagnosis but acoustic parameters for sustained vowels were within the normal range. Female disordered voices showed significantly longer PST duration than normal voices, including those in the 'below threshold' group. Overall differences for male voices were also significant. Results suggest that, at least for females, PST measurement from connected speech could provide a more sensitive indicator of disorder than traditional analysis of sustained vowels.

Discussions on the use of anti-retroviral drugs (ARVs) in developing countries have in the past focused on the limitations caused by the high cost of the drugs and by the lack of health system capacity to adequately deliver and make use of them (Colebunders et al. 2000; The New York Times 2001). An additional concern has been the risk of increasing resistance to ARVs if there were widespread inappropriate administration and lack of monitoring (Harries et al. 2001). Lately, however, including at the 2002 International AIDS Conference in Barcelona, there have been stronger calls for scaling up access to ARVs with less attention paid to these concerns and limitations, as expressed by Lange (2002): 'If we can get cold Coca-Cola and beer to every remote corner of Africa, it should not be impossible to do the same with drugs'.