Treating festinating speech with altered auditory feedback in Parkinson's disease: A preliminary report

Advanced speech symptoms in Parkinson's disease (PD), such as "festinating speech" or palilalia and frequent hesitations, are a clinical challenge. This preliminary report is part of a larger study testing the hypothesis that the use of altered auditory feedback (AAF) will improve speech intelligibility in patients with PD and more advanced speech impairment. Nine patients with PD and advanced speech impairment served as subjects. Blinded to the testing conditions (which were randomized for each subject except for the first baseline condition), the subjects produced reading, controlled monologue, picture description, and conversation samples of 30 seconds each under six testing conditions (two baseline, two placebo, and two feedback). The placebo and feedback conditions required subjects to wear an in-the-ear device in one ear. For each subject, an effective combination of delayed auditory feedback (DAF) and frequency altered feedback (FAF) was determined. Twenty graduate student clinicians blindly rated the samples for speech intelligibility and speaking rate. The results show that speech intelligibility was consistently improved under the feedback condition for monologue but not for reading tasks. The speaking rate rating remained unchanged for the monologue task but was statistically different for the reading task. The possible mechanism responsible for the improvement is suggested.