Listener Detection of Objectively Validated Acoustic Features of Speech in Huntington's Disease.

BACKGROUND: Subtle progressive changes in speech motor function and cognition begin prior to diagnosis of Huntington's disease (HD). OBJECTIVE: To determine the nature of listener-rated speech differences in premanifest and early-stage HD (i.e., PreHD and EarlyHD), compared to neurologically healthy controls. METHODS: We administered a speech battery to 60 adults (16 people with PreHD, 14 with EarlyHD, and 30 neurologically healthy controls), and conducted a cognitive test of processing speed/visual attention, the Symbol Digit Modalities Test (SDMT) on participants with HD. Voice recordings were rated by expert listeners and analyzed for acoustic and perceptual speech features. RESULTS: Listeners perceived subtle differences in the speech of PreHD compared to controls, including abnormal pitch level and speech rate, reduced loudness and loudness inflection, altered voice quality, hypernasality, imprecise articulation, and reduced naturalness of speech. Listeners detected abnormal speech rate in PreHD compared to healthy speakers on a reading task, which correlated with slower speech rate from acoustic analysis and a lower cognitive performance score. In early-stage HD, continuous speech was characterized by longer pauses, a higher proportion of silence, and slower rate. CONCLUSION: Differences in speech and voice acoustic features are detectable in PreHD by expert listeners and align with some acoustically-derived objective speech measures. Slower speech rate in PreHD suggests altered oral motor control and/or subtle cognitive deficits that begin prior to diagnosis. Speakers with EarlyHD exhibited more silences compared to the PreHD and control groups, raising the likelihood of a link between speech and cognition that is not yet well characterized in HD.

Effects of face masks on acoustic analysis and speech perception: Implications for peri-pandemic protocols.

Wearing face masks (alongside physical distancing) provides some protection against infection from COVID-19. Face masks can also change how people communicate and subsequently affect speech signal quality. This study investigated how three common face mask types (N95, surgical, and cloth) affected acoustic analysis of speech and perceived intelligibility in healthy subjects. Acoustic measures of timing, frequency, perturbation, and power spectral density were measured. Speech intelligibility and word and sentence accuracy were also examined using the Assessment of Intelligibility of Dysarthric Speech. Mask type impacted the power distribution in frequencies above 3 kHz for the N95 mask, and above 5 kHz in surgical and cloth masks. Measures of timing and spectral tilt mainly differed with N95 mask use. Cepstral and harmonics to noise ratios remained unchanged across mask type. No differences were observed across conditions for word or sentence intelligibility measures; however, accuracy of word and sentence translations were affected by all masks. Data presented in this study show that face masks change the speech signal, but some specific acoustic features remain largely unaffected (e.g., measures of voice quality) irrespective of mask type. Outcomes have bearing on how future speech studies are run when personal protective equipment is worn.

Speech in prodromal and symptomatic Huntington's disease as a model of measuring onset and progression in dominantly inherited neurodegenerative diseases.

Subtle motor and cognitive changes can manifest prior to diagnosis in many progressive neurological disorders. Most people with Huntington's disease (HD) develop dysarthria. Yet, how speech evolves, how the brain regulates speech in HD, and the clinical implications of these changes remain unclear. We reviewed existing literature on speech production in premanifest (PreHD) to symptomatic HD. A search of databases yielded 12 eligible studies. Nine of the twelve studies were included in the meta-analysis. Data suggest that speech in PreHD is characterized by impaired speech agility, phonatory function and speech rate. Over the disease course, speech gradually deteriorates across all subsystems of speech. Our findings indicate subtle changes in speech appear prior to a clinical diagnosis of HD. However, distinct patterns of decline and the magnitude of these deficits require further investigation. Our current understanding of speech impairment in HD relies on small cohort studies. Natural history studies documenting changes from premanifest to end stage may facilitate the development of speech as a marker of disease onset and treatment response.