Veronika Majerová

Imprecise vowel articulation as a potential early marker of Parkinson's disease: effect of speaking task.

The purpose of this study was to analyze vowel articulation across various speaking tasks in a group of 20 early Parkinsons disease (PD) individuals prior to pharmacotherapy. Vowels were extracted from sustained phonation, sentence repetition, reading passage, and monologue. Acoustic analysis was based upon measures of the first (F1) and second (F2) formant of the vowels /a/, /i/, and /u/, vowel space area (VSA), F2i/F2u and vowel articulation index (VAI). Parkinsonian speakers manifested abnormalities in vowel articulation across F2u, VSA, F2i/F2u, and VAI in all speaking tasks except sustained phonation, compared to 15 age-matched healthy control participants. Findings suggest that sustained phonation is an inappropriate task to investigate vowel articulation in early PD. In contrast, monologue was the most sensitive in differentiating between controls and PD patients, with classification accuracy up to 80%. Measurements of vowel articulation were able to capture even minor abnormalities in speech of PD patients with no perceptible dysarthria. In conclusion, impaired vowel articulation may be considered as a possible early marker of PD. A certain type of speaking task can exert significant influence on vowel articulation. Specifically, complex tasks such as monologue are more likely to elicit articulatory deficits in parkinsonian speech, compared to other speaking tasks.

Acoustic assessment of voice and speech disorders in Parkinson's disease through quick vocal test.

The disorders of voice and speech in Parkinson’s disease (PD) result from involvements in several subsystems including respiration, phonation, articulation, and prosody. We investigated the feasibility of acoustic measures for the identification of voice and speech disorders in PD, using a quick vocal test consisting of sustained phonation, diadochokinetic task, and running speech. Various traditional and novel acoustic measurements have been designed in order to be gender independent, represent all speech subsystems, reduce the time required for voice investigation, and provide a reliable automated assessment in practice.

Biochemical oxidative stress-related markers in patients with obstructive sleep apnea

Summary Background Obstructive sleep apnea (OSA) is a condition contributing to oxidative stress. The aim of this study was to ascertain if there is any connection between OSA and novel oxidative stress-related markers. Matrix metalloproteinases 2 and 9 (MMP-2, MMP-9), high sensitive C-reactive protein (hsCRP), pregnancy-associated plasma protein-A (PAPP-A), soluble receptors for advanced glycation end-products (sRAGE), zinc (Zn) and copper (Cu) were measured. Further biochemical markers were evaluated. Material/Methods Fifty-one men suspected for OSA indicated for night polygraphy were included. Apnea/hypopnea index (AHI), oxygen desaturation index (ODI), mean blood hemoglobin oxygen saturation (SpO2) and time of blood hemoglobin oxygen saturation below 90% (SpO2 <90%) were measured. Morning venous blood samples were taken. Results For body mass index (BMI) we found strong positive correlation with levels of Cu, MMP-9, hsCRP and fibrinogen, and negative correlation with sRAGE. Concerning ventilation parameters, we found positive correlation of ODI and SpO2 <90% with markers MMP-9 and hsCRP. sRAGE level correlated with AHI and ODI negatively. SpO2 correlated negatively with Cu, MMP-9, hsCRP and fibrinogen. There was no correlation between ventilation parameters and markers MMP-2, PAPP-A and Zn. Compared to severity of OSA, there was significant difference in levels of hsCRP and Cu between patients with AHI ≤5 and AHI ≥30 independent of BMI. Conclusions MMP-9, hsCRP, sRAGE and Cu seem to be strong predictors of oxidative stress in OSA patients. The strong correlation between oxidative stress-related markers and OSA is elucidated by connection of these to BMI, which is probably a primary condition of oxidative stress, but OSA is an additive condition.

Effects of Ropinirole Prolonged-Release on Sleep Disturbances and Daytime Sleepiness in Parkinson Disease

This study evaluated the effects of ropinirole prolonged-release (RPR) in comparison with ropinirole immediate-release (RIR) on sleep-related disorders in Parkinson disease (PD).Thirty-three PD patients (aged 62.5 [SD, 8] years; PD duration, 9 [SD, 4] years) were evaluated on a stable dose of RIR and 5 to 13 weeks after switch to the closest possible dose of RPR. The following questionnaires were administered: Epworth Sleepiness Scale, PD Sleep Scale, Pittsburgh Sleep Quality Index, REM Sleep Behavior Disorder Screening Questionnaire, and PD Questionnaire 39. We further monitored the occurrence of restless legs syndrome and sleep attacks (SAs). Motor disability was evaluated by PD diary and by Unified Parkinson Disease Rating Scale part 3 on medication (ON) and after medication withdrawal (OFF). In 8 patients with marked subjective sleep disturbance, polysomnography, and multiple sleep latency test were performed.After switching to RPR, there was an improvement in PD Sleep Scale (94.9 [SD, 23] vs 102.2 [SD, 27]; P < 0.05 corrected), Pittsburgh Sleep Quality Index (7.2 [SD, 3] vs 5.8 [SD, 3]; P < 0.05 corrected), Epworth Sleepiness Scale (14.1 [SD, 5] vs 12.0 [SD, 6]; P < 0.05 corrected) and Unified Parkinson Disease Rating Scale part 3 in the ON state (20.9 [SD, 10] 10 vs 17.6 [SD, 10]; P < 0.05 corrected). Thirteen patients reported disappearance of SAs on RPR. Polysomnography and multiple sleep latency test showed no changes in a subgroup of 8 patients after the switch to RPR.Ropinirole prolonged-release compared with RIR improved subjective quality of sleep, reduced daytime sleepiness, and led to disappearance of SAs in some patients possibly due to a more stable plasma level of ropinirole.

Horizontal and vertical eye movement metrics: What is important?

OBJECTIVE To assist other eye movement investigators in the design and analysis of their studies. METHODS We examined basic saccadic eye movements and smooth pursuit in the horizontal and vertical directions with video-oculography in a group of 145 healthy subjects between 19 and 82 years of age. RESULTS Gender and education level did not influence eye movement metrics. With age, the latency of leftward and vertical pro- and antisaccades increased (p<0.001), velocity of upward prosaccades decreased (p<0.001), gain of rightward and upward prosaccades diminished (p<0.001), and the error rate of antisaccades increased (p<0.001). Prosaccades and antisaccades were influenced by the direction of the target, resulting in a right/left and up/down asymmetry. The skewness of the saccade velocity profile was stable throughout the lifespan, and within the range of saccades analyzed in the present study, correlated with amplitude and duration only for antisaccades (p<0.001). CONCLUSIONS Some eye movement metrics must be separated by the direction of movement, others according to subject age, while others may be pooled. SIGNIFICANCE This study provides important information for new oculomotor laboratories concerning the constitution of subject groups and the analysis of eye movement metrics.

Validity of the Montreal Cognitive Assessment in the Detection of Cognitive Dysfunction in Huntington's Disease

The purpose of this study was to assess the convergent and discriminative validity of the Montreal Cognitive Assessment (MoCA) as a screening tool for cognitive dysfunction in Huntingtons disease (HD). Twenty HD patients with cognitive deficit and 23 normal controls (NC) without cognitive deficit were matched for age, sex, and education. The mean MoCA score was 20.5 (SD = 5.5) in HD and 27.5 (SD = 2.2) in NC. The MoCA correlated in both samples with the brief cognitive battery composite score (r = .81, p < .001). With the screening and diagnostic cutoff scores determined at <26 points, the MoCA showed a sensitivity of 94% and a specificity of 84% in the detection of cognitive dysfunction in HD. The area under the receiver-operating characteristics curve (95% confidence interval) for the MoCA was 0.90 (0.809–0.997), p < .001. Our results show that the MoCA is a suitable tool for assessing cognitive dysfunction in patients with HD.

Objective Acoustic Quantification of Phonatory Dysfunction in Huntington's Disease

Purpose Although speech motor changes are reported as a common sign of Huntington’s disease (HD), the most prominent signs of voice dysfunction remain unknown. The aim of the current study was to explore specific changes in phonatory function in subjects with HD. Method 34 subjects with HD and 34 age- and sex-matched healthy controls were examined. Participants performed sustained vowel phonation for subsequent analyses of airflow insufficiency, aperiodicity, irregular vibrations of vocal folds, signal perturbations, increased noise, and articulation deficiency. In total, 272 phonations were collected and 12 voice parameters were extracted. Subsequently, a predictive model was built to find the most salient patterns of voice disorders in HD. The results were also correlated with disease severity according to the Unified HD Rating Scale (UHDRS) motor score. Results Subjects with HD showed deterioration in all investigated phonatory functions. Irregular pitch fluctuations, sudden phonation interruption, increased noise, and misplacement of articulators were found to be most significant patterns of phonatory dysfunction in HD (p<0.001). The combination of these four dysphonia aspects contributed to the best classification performance of 94.1% (sensitivity: 95.1%; specificity: 93.2%) in the separation of HD patients from healthy participants. Our results further indicated stronger associations between sudden phonation interruption and voluntary components of the UHDRS (r = −0.48, p<0.01) and between misplacement of articulators and involuntary components of the UHDRS (r = 0.52, p<0.01). Conclusions Our configuration of phonatory features can detect subtle voice abnormalities in subjects with HD. As impairment of phonatory function in HD was found to parallel increasing motor involvement, a qualitative description of voice dysfunction may be helpful to gain better insight into the pathophysiology of the vocal mechanism.

Disturbance of real space navigation in moderately advanced but not in early Huntington's disease

BACKGROUND Visuospatial skills including spatial navigation are known to be impaired in Huntingtons disease. Spatial navigation comprises two navigational frameworks, allocentric and egocentric. Several studies have associated the allocentric navigation with the hippocampus and the egocentric navigation with the striatum. The striatum is predominantly impaired from the early stages of Huntingtons disease. OBJECTIVE To find whether spatial navigation impairment is present in the early stages of Huntingtons disease and to test the hypothesis that the egocentric navigation is predominantly affected compared to the allocentric navigation. METHODS In nineteen patients with Huntingtons disease the egocentric and the allocentric navigation skills were tested using the Blue Velvet Arena, a human analog of Morris Water Maze, and compared to nineteen age and gender-matched healthy controls. Cognitive functions, with emphasis on the executive functions, were also assessed. RESULTS The spatial navigation skills deteriorated with the increasing motor impairment in Huntingtons disease. These changes only became apparent in patients with moderate functional impairment. No difference between the egocentric and the allocentric skills was seen. DISCUSSION Spatial navigation deficit is not an early marker of the cognitive dysfunction in Huntingtons disease. We speculate that the striatal circuitry that is known to degenerate early in the course of Huntingtons disease is not directly associated with the spatial navigation.

Patterns of gene flow and selection across multiple species of Acrocephalus warblers: footprints of parallel selection on the Z chromosome

BackgroundUnderstanding the mechanisms and selective forces leading to adaptive radiations and origin of biodiversity is a major goal of evolutionary biology. Acrocephalus warblers are small passerines that underwent an adaptive radiation in the last approximately 10 million years that gave rise to 37 extant species, many of which still hybridize in nature. Acrocephalus warblers have served as model organisms for a wide variety of ecological and behavioral studies, yet our knowledge of mechanisms and selective forces driving their radiation is limited. Here we studied patterns of interspecific gene flow and selection across three European Acrocephalus warblers to get a first insight into mechanisms of radiation of this avian group.ResultsWe analyzed nucleotide variation at eight nuclear loci in three hybridizing Acrocephalus species with overlapping breeding ranges in Europe. Using an isolation-with-migration model for multiple populations, we found evidence for unidirectional gene flow from A. scirpaceus to A. palustris and from A. palustris to A. dumetorum. Gene flow was higher between genetically more closely related A. scirpaceus and A. palustris than between ecologically more similar A. palustris and A. dumetorum, suggesting that gradual accumulation of intrinsic barriers rather than divergent ecological selection are more efficient in restricting interspecific gene flow in Acrocephalus warblers. Although levels of genetic differentiation between different species pairs were in general not correlated, we found signatures of apparently independent instances of positive selection at the same two Z-linked loci in multiple species.ConclusionsOur study brings the first evidence that gene flow occurred during Acrocephalus radiation and not only between sister species. Interspecific gene flow could thus be an important source of genetic variation in individual Acrocephalus species and could have accelerated adaptive evolution and speciation rate in this avian group by creating novel genetic combinations and new phenotypes. Independent instances of positive selection at the same loci in multiple species indicate an interesting possibility that the same loci might have contributed to reproductive isolation in several speciation events.