Ing. Michal Šimek

Background Research on the possible influence of lateralised basal ganglia dysfunction on speech in Parkinson's disease is scarce. This study aimed to compare speech in de-novo, drug-naive patients with Parkinson's disease (PD) with asymmetric nigral dopaminergic dysfunction, predominantly in either the right or left hemisphere. Methods Acoustic analyses of reading passages were performed. Asymmetry of nigral dysfunction was defined using dopamine transporter-single-photon emission CT (DAT-SPECT). Results From a total of 135 de novo patients with PD assessed, 47 patients had a lower right and 36 lower left DAT availability in putamen based on DAT-SPECT. Patients with PD with lower left DAT availability had higher dysarthria severity via composite dysarthria index compared with patients with lower right DAT availability (p=0.01). Conclusion Our data support the crucial role of DAT availability in the left putamen in speech. This finding might provide important clues for managing speech following deep brain stimulation.

Head tremor is a common symptom in both essential tremor (ET) and cervical dystonia (CD). Distinguishing between these two conditions can be challenging in clinical practice, particularly when head tremor is the dominant feature. Our goal was to explore the potential of speech assessment in recognizing the mechanisms of head tremor in patients with ET and CD. Objective acoustic vocal assessments of oral diadochokinesis, phonatory stability, vocal tremor, and speech timing were performed. Of the 93 patients assessed, 39 had cervical dystonia (CD) with head tremor, 38 had ET with head tremor (ET-HT), and 16 had ET with no head tremor (ET-nHT). Compared to both CD and ET-nHT, ET-HT showed irregular sequential motion rate, excessive pitch fluctuations, increased noise, and higher extent of vocal vibrato. Compared to CD, ET-HT also demonstrated slower sequential motion rate, prolonged pauses, and a slower articulation rate. Additionally, ET-HT had more pronounced vocal tremolo compared to ET-nHT. Speech assessment provided discrimination between the CD and ET-HT groups with an area under curve of 0.80. This study underscores the promising potential of speech analysis in recognizing mechanisms of head tremor in patients with ET or CD, revealing more severe and distinct speech impairments in ET-HT patients compared to those with CD.

We present an open-source application for mobile devices called VASIR that provides a reliable and sensitive tool for accessible intelligibility rating using visual analog scales. VASIR is validated by examining the intelligibility in 23 Parkinson's disease (PD) patients treated with subthalamic nucleus deep brain stimulation (DBS) in on and off stimulation states, and 23 healthy controls. Two rater groups of naive and expert listeners performed intelligibility ratings using the provided application. An excellent intraclass correlation was found in both the naive (ICC = 0.97) and expert (ICC = 0.95) groups. Both listener groups were able to confidently differentiate between the controls and DBS groups (p < 0.001) whereas only the expert group was able to find statistically significant differences in intelligibility between on and off stimulation states (p = 0.031).

Background: Speech dysfunction represents one of the initial motor manifestations to develop in Parkinson's disease (PD) and is measurable through smartphone. Objective: The aim was to develop a fully automated and noise-resistant smartphone-based system that can unobtrusively screen for prodromal parkinsonian speech disorder in subjects with isolated rapid eye movement sleep behavior disorder (iRBD) in a real-world scenario. Methods: This cross-sectional study assessed regular, everyday voice call data from individuals with iRBD compared to early PD patients and healthy controls via a developed smartphone application. The participants also performed an active, regular reading of a short passage on their smartphone. Smartphone data were continuously collected for up to 3 months after the standard in-person assessments at the clinic. Results: A total of 3525 calls that led to 5990 minutes of preprocessed speech were extracted from 72 participants, comprising 21 iRBD patients, 26 PD patients, and 25 controls. With a high area under the curve of 0.85 between iRBD patients and controls, the combination of passive and active smartphone data provided a comparable or even more sensitive evaluation than laboratory examination using a high-quality microphone. The most sensitive features to induce prodromal neurodegeneration in iRBD included imprecise vowel articulation during phone calls (P = 0.03) and monopitch in reading (P = 0.05). Eighteen minutes of speech corresponding to approximately nine calls was sufficient to obtain the best sensitivity for the screening. Conclusion: We consider the developed tool widely applicable to deep longitudinal digital phenotyping data with future applications in neuroprotective trials, deep brain stimulation optimization, neuropsychiatry, speech therapy, population screening, and beyond.

This study investigated whether voice quality is differentially affected in two distinct basal ganglia disorders causing hypokinetic and hyperkinetic dysarthria, including effects of gender and speaking task. The sustained vowel phonations and monologues of 40 de novo Parkinson's disease (PD) patients, 40 Huntington's disease (HD) patients, and 40 healthy control participants were evaluated. Using cepstral peak prominence extracted from sustained phonation, differences from controls were found for male and female HD patients (p < 0.05) but only male PD patients (p < 0.05). Using the glottal-to-noise excitation ratio obtained from monologue, differences from controls were detected for male and female PD groups (p < 0.05) but only male HD group (p < 0.05). In general, female patients show better voice quality. Our findings highlight that selecting suitable acoustic measures and speaking material is essential for adequate evaluation of dysphonia severity across differing etiologies.

Dysphonia is a common speech disruption in people with Parkinson's (PD) and Huntington's (HD). Though the glottal source analysis (GSS) yielded promising results in PD, no study analyzed utility of the GSS in HD. In addition, the potential GSS sex-dependency remains unknown. This study examines sustained vowel phonations provided by 40 PD, 40 HD and 40 age- and sex-matched healthy participants using six GSS features including normalized amplitude quotient, quasi-open quotient, magnitude difference of first two spectral peaks, harmonic richness factor, maximum dispersion quotient (MDQ), and peak slope. Our results showed significant differences in HD men and women compared to the healthy counterpart, suggesting breathiness (p < 0.01), tension (p < 0.001), and decreased timbre (p < 0.01) in HD. Reported sex-related differences highlighted the sensitivity of the GSS towards the speaker's sex. The correlation analysis revealed significant relationship between disease severity and MDQ in HD men.

Background: Patients with synucleinopathies frequently display language abnormalities. However, whether patients with isolated rapid eye movement sleep behavior disorder (iRBD) have prodromal language impairment remains unknown. Objectives: We examined whether the linguistic abnormalities in iRBD can serve as potential biomarkers for conversion to synucleinopathy, including the possible effect of mild cognitive impairment (MCI), speaking task, and automation of analysis procedure. Methods: We enrolled 139 Czech native participants, including 40 iRBD without MCI and 14 iRBD with MCI compared to 40 PD without MCI, 15 PD with MCI, and 30 healthy controls. Spontaneous discourse and story tale narrative were transcribed and linguistically annotated. A quantitative analysis was performed computing 3 linguistic features. Human annotations were compared to fully-automated annotations. Results: Compared to controls, iRBD patients showed poorer content density, reflecting the reduction of content words and modifiers. Both PD and iRBD subgroups with MCI manifested less occurrence of unique words and a higher number of n-grams repetitions, indicating poorer lexical richness. The spontaneous discourse task demonstrated language impairment in iRBD without MCI with an area under the curve of 0.72, while the story tale narrative task better reflected the presence of MCI, discriminating both PD and iRBD subgroups with MCI from controls with an area under the curve of up to 0.81. A strong correlation between manually and automatically computed results was achieved. Conclusions: Linguistic features might provide a reliable automated method for detecting cognitive decline due to prodromal neurodegeneration in subjects with iRBD, providing critical outcomes for future therapeutic trials.

Although cepstral peak prominence (CPP) and its smooth variant (CPPS) are considered robust acoustic measures for the evaluation of dysphonia, whether they are sensitive to capture early voice changes in Parkinson’s disease (PD) has not yet been explored. This study aimed to investigate voice changes via CPP measures in idiopathic rapid eye movement sleep disorder behaviour (iRBD), a special case of prodromal neurodegeneration, and in both newly diagnosed, and advanced-stage PD patients using different speaking tasks across noise-free and noisy environments. The sustained vowel phonation, the reading of passages and the monologues of 60 early-stage untreated PD, 30 advanced-stage PD, 60 iRBD, and 60 healthy control (HC) participants were evaluated. We found significant differences between both PD groups and the controls in sustained phonation via CPP (p < 0.05) and CPPS (p < 0.01) and in monologue via CPP (p < 0.01), although neither CPP nor CPPS measures were sufficiently sensitive to capture possible prodromal dysphonia in iRBD. The quality of both CPP and CPPS measures was influenced substantially by the addition of ambient noise. We anticipated that CPP measures might serve as a promising digital biomarker in assessing dysphonia from the early stages of PD.