Perceptual Analyses of Spasmodic Dysphonia Before and After Treatment

Abstract

To evaluate expert listeners' perceptions of voice and fluency in persons with adductor spasmodic dysphonia (ADSD) before and after treatment with botulinum toxin type A (Botox), as a function of initial severity of the disorder (while controlling for patients' age at injection). Design: Simple before-and-after trial with blinded randomized listener judgments. Setting: Ambulatory care clinic at a single medical center. Participants: Forty-two consecutive patients with ADSD who underwent examination, with a 3-to 6-week followup, after initial botulinum toxin type A injection. There were also 42 age-and sex-matched healthy control subjects. Interventions: Injections of botulinum toxin type A into the thyroarytenoid muscle(s). Main Outcome Measures: Computer-implemented visual analog scaling judgments of voice quality and speech fluency made by expert listeners under psychoacoustically controlled conditions. Results: Response to botulinum toxin type A varied markedly as a function of pretreatment severity of ADSD. More severe initial symptoms exhibited greater magnitudes of improvement. Patients with mild dysphonia did not exhibit pretreatment to posttreatment change. Following treatment, voice and fluency remained significantly (PϽ.05) poorer in ADSD than in healthy speakers. Older patients exhibited less improvement than younger patients when the effect of initial severity was statistically controlled. Conclusions: Voice quality and fluency improved for most patients following treatment, but older patients and those with milder dysphonia exhibited the least optimal responses to the procedure. Patients who were profoundly impaired demonstrated the greatest amount of improvement. Computer-implemented visual analog scaling provided a reliable clinical tool for determining treatment-related changes in those with ADSD.

Acoustic Measures of Phonation during Connected Speech in Adductor Spasmodic Dysphonia

“…Connected speech samples from 10 female speakers diagnosed with ADSD for at least four years prior to the study were selected from a larger archival database of recordings from 42 consecutive cases with ADSD who underwent initial BT injection [20]. Their clinical characteristics are provided in Table 1.…”

“…The purpose of the present study is to demonstrate the effectiveness of some alternative approaches to extraction and measurement of f 0 and associated features of amplitude and SNR in connected speech. These are both continuous and ratio in scale, and were obtained from an archival data base of recordings of speakers with ADSD pre/post BT treatment and of non-dysphonic healthy control (NHC) speakers [20]. Such measures may prove useful toward developing a more complete profile of voice characteristics in ADSD before and after treatment.…”

Expert System-Type Approach to Voice Disorders: Scheduling Botulinum Toxin Treatment for Adductor Spasmodic Dysphonia

“…Not only do patients themselves feel the improvement, this improvement can also be detected -in a blind-control situation -both by measurements and by expert listeners [3,7]. Specifically, expert listeners "perceived significant improvement in ADSD connected speech at one month following botulinum toxin injection relative to preinjection levels" [3].…”

“…Specifically, expert listeners "perceived significant improvement in ADSD connected speech at one month following botulinum toxin injection relative to preinjection levels" [3].…”

“…The problem with BT treatment is that while there have been studies evaluating pre-and post-BT treatment changes in the voice and speech fluency of ADSD individuals (see, e.g., [3,7,8]), the nature of speech stability of individuals with spasmodic dysphonia (SD) treated with botulinum toxin (BT) is still poorly understood.…”