Parkinson’s Speech

Our radical idea is that there are at least two speech disorders associated with Parkinson’s:

  • Hypophonia or low vocal volume is well known. Multitalker babble noise increases vocal volume 3 to 10 dB via the Lombard effect. Our current devices don’t provide multitalker babble noise.
  • Festinating speech is a pacing disorder in which one’s words run together. Our DAF devices pace and slow down your speech 20-40%.
  • We’ve seen a small number of patients who respond to our FAF devices with increased articulation.

We generally don’t see carryover fluency with Parkinson’s patients. There are exceptions.

We’ve measured intelligibility increases of 85–625% with our devices.

Parkinson’s patients do best with a headset. A headset is big and easy to put on and take off. The microphone is close to your mouth and picks up your voice even when your volume is low.


  • Mr. B is in his 70s. His speech is rapid and unintelligible. He read at 191 words per minute with 4% intelligibility. With DAF set at 75ms and training to slow down, he read at 113 words per minute and 25% intelligibility. Results: 625% increase in intelligibility, 41% decrease in speaking rate.
  • Michael read at 148 words per minute and 5% intelligibility. His vocal volume was adequate. With his SmallTalk set at 70 ms and -0.4 octaves his speaking rate slowed to 122 wpm and intelligibility rose to 16%. Results: 300% increase in speech intelligibility, 20% decrease in speaking rate.
  • Jesse is 61 years old and has moderate Parkinson’s. His baseline had adequate vocal volume and 32% intelligibility. With 88ms DAF and -0.25 FAF he tried to talk as slowly as he could. Intelligibility rose to 49%. Jesse than took off the device and spoke at a normal speaking rate and 59% intelligibility. Results: 85% increase in intelligibility, carryover after removing the device.
  • Anne Marie’s DBS eliminated a tremor but made her unable to walk and reduced her vocal volume. Her articulation is clear and she has no pacing problems. Standard Babble Noise increased her volume 10 dB but she slurred words. Advanced Babble Noise increased her volume 7 dB without slurred words. Results: 7 dB increase in vocal volume, excellent intelligibility and pacing, no hearing impairment.


[1] Darling, M. & Huber, J. Changes to Articulatory Kinematics in Response to Loudness Cues in Individuals With Parkinson’s Disease. Journal of Speech, Language & Hearing Research, Oct 2011; 54: 1247-1259. This paper reports that multitalker babble noise induced a 10 dB increase in vocal volume in persons with Parkinson’s.

[2] Blanchet, P., & Snyder, G. Speech Rate Treatments For Individuals With Dysarthria. Perceptual and Motor Skills, Vol. 110, Iss. 3 (June 2010) doi: 10.2466/pms.110.3.965-982.

[3] Kessler, L., Solomon, N., & Grill, S. Effects of altered auditory feedback on festinating speech in Parkinson’s disease (conference presentation, unpublished). This longitudinal study addressed short- and long-term effects of DAF and FAF on speech rate, naturalness, intelligibility, and speech disability (modified Voice Handicap Index, mVHI) in 6 men with Parkinson’s and festinating speech. Participants provided repeated-baseline data, wore a binaural SmallTalk daily, and returned monthly for 6 months for retesting. Two participants were non-compliant for wearing the device and withdrew from the study before its completion. The four who completed the study reported or demonstrated improved speech while wearing the device. Three participants purchased it at the conclusion of the study and continued to report benefits 2 years later.

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