Sabine Skodda

Speech rate and rhythm in Parkinson's disease

Articulatory rate and pause time in a standardized reading task in Parkinsons disease (PD) patients in correlation to disease duration and severity as compared to healthy controls were analyzed. In 121 PD patients and 70 healthy controls, an acoustical analysis was performed on the first and last sentence of a standardized 170‐syllabic text, using a commercial audio software. Articulatory rate and speech to pause ratios were calculated by measuring the length of each syllable and each pause both at the end of words and within polysyllabic words. No significant difference in overall articulatory rate was found between PD patients and controls. Both groups showed an accelerated speech rate in the last sentence compared to the first; however, PD patients had a higher speech acceleration than did controls. PD patients exhibited a significantly reduced percental pause duration in relation to total speech time in the first sentence and a reduced percental pause time within polysyllabic words. PD patients made significantly less but longer pauses at the end of words and less pauses within polysyllabic words. UPDRS III showed an inverse relation to number and rate of intraword pauses, and disease duration was negatively correlated with articulatory rate. The characteristics of parkinsonian speech feature was not only a stronger acceleration of articulation rate in the course of speaking but also a significant reduction of the total numbers of pauses, indicating an impaired speech rhythm and timing organization.

Impairment of Vowel Articulation as a Possible Marker of Disease Progression in Parkinson's Disease

Purpose The aim of the current study was to survey if vowel articulation in speakers with Parkinsons disease (PD) shows specific changes in the course of the disease. Method 67 patients with PD (42 male) and 40 healthy speakers (20 male) were tested and retested after an average time interval of 34 months. Participants had to read a given text as source for subsequent calculation of the triangular vowel space area (tVSA) and vowel articulation index (VAI). Measurement of tVSA and VAI were based upon analysis of the first and second formant of the vowels /α/, /i/and /u/ extracted from defined words within the text. Results At first visit, VAI values were reduced in male and female PD patients as compared to the control group, and showed a further decrease at the second visit. Only in female Parkinsonian speakers, VAI was correlated to overall speech impairment based upon perceptual impression. VAI and tVSA were correlated to gait impairment, but no correlations were seen between VAI and global motor impairment or overall disease duration. tVSA showed a similar reduction in the PD as compared to the control group and was also found to further decline between first and second examination in female, but not in male speakers with PD. Conclusions Measurement of VAI seems to be superior to tVSA in the description of impaired vowel articulation and its further decline in the course of the disease in PD. Since impairment of vowel articulation was found to be independent from global motor function but correlated to gait dysfunction, measurement of vowel articulation might have a potential to serve as a marker of axial disease progression.

Gender-Related Patterns of Dysprosody in Parkinson Disease and Correlation Between Speech Variables and Motor Symptoms

Explorative analysis of prosodic parameters in patients with Parkinson disease (PD) and in healthy controls in correlation to gender, disease-specific parameters, and motor symptoms. Acoustical analysis was performed on 169 patients with PD and 64 age-matched healthy controls based on a four sentence-reading task. Assessment of motor impairment was performed on the basis of Unified Parkinsons Disease Rating Scale/Motor Score III and further symptom-related subscores. F(0) variability was reduced in male and female PD patients, whereas mean F(0) was found to be elevated in male patients with PD only. No significant difference in overall articulatory rate was found between PD patients and controls, but patients showed a reduction of percentual pause time within polysyllabic words (Pin w%). Female PD patients showed an additional reduction of percentual pause ratio (PR%). Variables of intonation and articulatory rate were not correlated to each other. Strong correlations were seen between some distinct prosodic variables and the axial and akinesia parkinsonian symptoms with some gender-related particularities. Reduction of F(0) variability and Pin w% are the most conspicuous features of parkinsonian dysprosody with some further gender-related characteristics. Changes of intonation variability and speech velocity seem to be controlled by different pathophysiological conditions. In consideration of some gender differences, several distinct aspects of dysprosody can be interpreted as axial and akinesia symptoms of PD.

Automatic detection of Parkinson's disease in running speech spoken in three different languages.

The aim of this study is the analysis of continuous speech signals of people with Parkinsons disease (PD) considering recordings in different languages (Spanish, German, and Czech). A method for the characterization of the speech signals, based on the automatic segmentation of utterances into voiced and unvoiced frames, is addressed here. The energy content of the unvoiced sounds is modeled using 12 Mel-frequency cepstral coefficients and 25 bands scaled according to the Bark scale. Four speech tasks comprising isolated words, rapid repetition of the syllables /pa/-/ta/-/ka/, sentences, and read texts are evaluated. The method proves to be more accurate than classical approaches in the automatic classification of speech of people with PD and healthy controls. The accuracies range from 85% to 99% depending on the language and the speech task. Cross-language experiments are also performed confirming the robustness and generalization capability of the method, with accuracies ranging from 60% to 99%. This work comprises a step forward for the development of computer aided tools for the automatic assessment of dysarthric speech signals in multiple languages.

Aspects of speech rate and regularity in Parkinson's disease.

The hypokinetic dysarthria of Parkinsons disease (PD) has been defined as a multidimensional impairment leading to abnormalities in speech breathing, phonation, articulation and prosody. The aspect of prosody can be subdivided into further dimensions, as for example stress and accentuation, intonation variability and speech rate and regularity. According to available data from literature and findings of our own published studies, the present review illuminates the concept that inconstancies of speech fluency in PD are characterized by modifications of the arrangement of speech pauses and by a tendency of pace acceleration in the course of the performance. Furthermore, on the level of single utterances, Parkinsonian speakers feature significant difficulties to steadily repeat single syllables without accelerating or slowing down the pace as we were able to show in a series of published investigations. Evidence from literature and our own work justifies the hypothesis that the characteristic abnormalities in speech articulatory rate and regularity might serve as a marker of disease progression in PD.

Characterization Methods for the Detection of Multiple Voice Disorders: Neurological, Functional, and Laryngeal Diseases

This paper evaluates the accuracy of different characterization methods for the automatic detection of multiple speech disorders. The speech impairments considered include dysphonia in people with Parkinsons disease (PD), dysphonia diagnosed in patients with different laryngeal pathologies (LP), and hypernasality in children with cleft lip and palate (CLP). Four different methods are applied to analyze the voice signals including noise content measures, spectral-cepstral modeling, nonlinear features, and measurements to quantify the stability of the fundamental frequency. These measures are tested in six databases: three with recordings of PD patients, two with patients with LP, and one with children with CLP. The abnormal vibration of the vocal folds observed in PD patients and in people with LP is modeled using the stability measures with accuracies ranging from 81% to 99% depending on the pathology. The spectral-cepstral features are used in this paper to model the voice spectrum with special emphasis around the first two formants. These measures exhibit accuracies ranging from 95% to 99% in the automatic detection of hypernasal voices, which confirms the presence of changes in the speech spectrum due to hypernasality. Noise measures suitably discriminate between dysphonic and healthy voices in both databases with speakers suffering from LP. The results obtained in this study suggest that it is not suitable to use every kind of features to model all of the voice pathologies; conversely, it is necessary to study the physiology of each impairment to choose the most appropriate set of features.

Instability of syllable repetition in Parkinson's disease—Influence of levodopa and deep brain stimulation

The aim of this study was to test the hypothesis of a fundamental impairment of vocal pace performance in Parkinsons disease (PD) based on a syllable repetition paradigm and the influence of levodopa and deep brain stimulation of the subthalamic nucleus (STN‐DBS). Twenty‐two PD patients under stable dopaminergic medication, 14 patients with STN‐DBS, and 30 controls were tested. Participants had to repeat the syllable /pa/ in a steady pace. Percental coefficient of variance (COV) of interval length was measured for the description of pace stability. Patients were tested in the OFF state and again in the ON state after levodopa administration or ongoing STN‐DBS. COV was elevated in both PD subgroups. COV was not influenced by levodopa administration but showed a further deterioration under STN‐DBS. The impaired syllable repetition capacity shows similarities to the patterns of more complex speech rhythm abnormalities in PD and therefore might share the same pathophysiology.

Effect of Subthalamic Stimulation on Voice and Speech in Parkinson’s Disease: For the Better or Worse?

Background: Deep brain stimulation of the subthalamic nucleus, although highly effective for the treatment of motor impairment in Parkinson’s disease (PD), can induce speech deterioration in a subgroup of patients. The aim of the current study was to survey (1) if there are distinctive stimulation effects on the different parameters of voice and speech and (2) if there is a special pattern of preexisting speech abnormalities indicating a risk for further worsening under stimulation. Methods: N = 38 patients with PD had to perform a speech test without medication with stimulation ON (StimON) and stimulation OFF (StimOFF). Speech samples were analyzed: (1) according to a four-dimensional perceptual speech score and (2) by acoustic analysis to obtain quantifiable measures of distinctive speech parameters. Results: Quality of voice was ameliorated with StimON, and there were trends of increased loudness and better pitch variability. N = 8 patients featured a deterioration of speech with StimON, caused by worsening of articulation or/and fluency. These patients already had more severe overall speech impairment with characteristic features of articulatory slurring and articulatory acceleration under StimOFF condition. Conclusion: The influence of subthalamic StimON Parkinsonian speech differs considerably between individual patients, however, there is a trend to amelioration of voice quality and prosody. Patients with stimulation-associated speech deterioration featured higher overall speech impairment and showed a distinctive pattern of articulatory abnormalities at baseline. Further investigations to confirm these preliminary findings are necessary to allow neurologists to pre-surgically estimate the individual risk of deterioration of speech under stimulation.

Instability of syllable repetition as a marker of disease progression in Parkinson's disease: a longitudinal study.

Parkinsonian speakers show a tendency to articulatory acceleration and have difficulties to keep the steady pace of repeated syllables. The aim of this study was to analyse the stability of motor speech performance based upon a syllable repetition paradigm during the course of disease to find a potential marker of disease progression in Parkinsons disease (PD). 58 patients withPD and 35 controls were tested and re‐tested after at least 12 months (mean: 33.40/range: 12–88). In the PD group, motor impairment was similar at first and second visit. Participants had to repeat the syllable /pa/ in a self chosen steady pace. Percental coefficient of variance (COV) of interval length was measured for description of pace stability throughout the performance. Percental pace acceleration (%PA) was based upon a comparison of the speed of syllable repetition in the first and second half of the task. Patients with PD showed a significant elevation of COV and %PA indicating an instability of syllable repetition and a tendency to pace acceleration in the course of performing. Furthermore, in the PD group, COV and %PA showed a significant deterioration from first to second examination. Instability of steady syllable repetition in PD shows characteristic changes during the course of the disease, but no correlation with general motor impairment. Therefore, the underlying mechanism may be independent from dopaminergic deficits. The potential role of impaired syllable repetition as a marker of non‐dopaminergic disease progression in PD needs validation by further studies.

Towards an automatic monitoring of the neurological state of Parkinson's patients from speech

The suitability of articulation measures and speech intelligibility is evaluated to estimate the neurological state of patients with Parkinsons disease (PD). A set of measures recently introduced to model the articulatory capability of PD patients is considered. Additionally, the speech intelligibility in terms of the word accuracy obtained from the Google® speech recognizer is included. Recordings of patients in three different languages are considered: Spanish, German, and Czech. Additionally, the proposed approach is tested on data recently used in the INTERSPEECH 2015 Computational Paralinguistics Challenge. According to the results, it is possible to estimate the neurological state of PD patients from speech with a Spearmans correlation of up to 0.72 with respect to the evaluations performed by neurologist experts.