Voice abnormalities and their relation with motor dysfunction in Parkinson's disease

Objective – To evaluate changes in perceptual and several acoustic parameters of voice in patients with Parkinson’s disease (PD) and to find out any relation with these parameters and motor components of Unified Parkinson’s Disease Rating Scale (UPDRS) in this patient group. Materials and methods – Twenty patients with PD (12 male and 8 female) were given objective and subjective voice tests and results were compared with those of 20 age‐ and sex‐matched controls. Patient's perceptual voice analysis was assessed using GRBAS scale including Grade of Dysphonia, Roughness, Breathiness, Asthenia and Strain items. Measurements for objective voice analysis, acoustic assessment tests including frequency perturbation [jitter (jitt)%], intensity perturbation [shimmer (shim)%], noise to harmonic ratio (NHR), fundamental frequency (F0), variability of fundamental frequency (vF0), diadochokinetic rate (DDK) and maximum phonation time (MPT) were used. An assessment of disability caused by voice disorders was scored according to the Voice Handicap Index (VHI) by the patient. All subjects also underwent videolaryngostroboscopic (VLS) examination. Motor components of UPDRS and acoustic parameters of voice were investigated for any correlations. Results – Compared with controls, roughness (P = 0.15), breathiness (P = 0.004) and asthenia (P = 0.031) values of males and breathiness (P = 0.043) and asthenia (P = 0.023) values of females were higher in patients with PD. Mean VHI scores of patients with PD were higher for both male and female patients (P = 0.0001 for male, P = 0.002 for female). The mean values for MPT (P = 0.02) and DDK (P = 0.025) were shorter in patients with PD. Jitt%, shim% and mean F0 values were similar among the two groups. But mean vF0 values were significantly higher in male patients with PD (P = 0.05). On VLS examination, non‐closure glottic pattern was found to be more frequent in the PD group. Conclusion – Although it is well known that pathophysiological changes in PD affect the voice, the present study found only few significant correlations between motor component of UPDRS and voice parameters.     

Voice acoustic changes during bilateral subthalamic stimulation in patients with Parkinson's disease

Objectives

The purpose of this study was to investigate the effects of bilateral subthalamic nucleus deep brain stimulation on the phonation of patients with Parkinson's disease in three drug-free conditions: (1) stimulation off, (2) with clinically optimised stimulation parameters, and (3) subthreshold overstimulation, in order to detect differences following voice analysis.

Patients and methods

Conversational speech and sustained vowel sounds /a/, /i/, /o/, /u/ and high /i/ were recorded from 22 PD patients. Perceptual analysis, perturbation jitter, shimmer, noise-to-harmonics ratio, and nonlinear dynamic analysis (NDA) with detrended fluctuation analysis and recurrence period density entropy were measured and compared to the above conditions. Quadratic discriminant analysis (QDA) was used to investigate stimulation conditions for given acoustic data.

Results

The changes of perturbation measurements for the above conditions were not significant. With differences between vowels, NDA showed more significant changes and more powerful correlation with perceptual scores than perturbation measurements. NDA was significantly more sensitive during the QDA of the conditions.

Conclusions

Acoustic voice analysis of sustained vowels can help with recognizing the overstimulated condition, and, with an appropriate test battery and software package including nonlinear dynamic analysis, it can be a valuable tool for fine adjustments of stimulation parameters.     

Acoustic voice assessment in Parkinson's disease patients submitted to posteroventral pallidotomy

Long-term complications in levodopa treated Parkinson's disease (PD) patients caused a resurgence of interest in pallidotomy as an option of treatment. However, postoperative complications such as speech disorders can occur. PURPOSE: The aim of this study is to evaluate the acoustic voice in PD patients, before and after posteroventral pallidotomy. METHOD: Twelve patients with PD were submitted to neurological and voice assessments during the off and on phases, in the pre-operative, 1st and 3rd post-operative months. The patients were evaluated with the UPDRS and the vocal acoustic parameters -- f0, NHR, jitter, PPQ, Shimmer, APQ (using the software MultiSpeech-Kay Elemetrics-3700). RESULTS: The off phase UPDRS scores revealed a tendency to improvement at the 1st month and the off phase worsened. The shimmer and APQ improved. CONCLUSION: This study shows that pallidotomy has little improvement on functional use of communication of PD patients.     

Progression of dysprosody in Parkinson's disease over time—A longitudinal study

Parkinsonian speech or hypokinetic dysarthria results from a multidimensional impairment of phonation, articulation, and prosody. Although the dysprosody in Parkinson's disease (PD) is well described (alterations in speech rate and pause time, speech intensity and pitch variation), little is known about alterations of these single prosodic parameters over a longer time course. The objective of this study is to analyze changes of speech rate and pitch variation in patients with PD over time and to compare these findings with healthy controls. Patients with PD (N = 50; 27 male and 23 female) and n = 50 age‐matched healthy controls (25 male, 25 female) were tested and retested after at least 7 months (mean: 25.02; median: 21; SD: 17.44; range: 7–79 months). In the PD group, motor impairment according to UPDRS motor score was similar at first and second visit. The participants had to accomplish a standardized four sentence reading task. The acoustical analysis was performed using a standard head‐worn microphone for voice recordings and commercial audio software (WaveLab®). For the determination of intonation based upon fundamental frequency (F₀) variation, we used a computer analysis program (Praat®). Articulatory velocity was determined by measurement of syllable rate and pause ratios. In the PD group, total speech rate (syllables per second related to total speech time/TSR) and net speech rate declined from first to second examination, especially in the male patients, but showed no significant differences to the control group. The course of pitch variation revealed some gender particularities. Whereas female patients' pitch variability declined over time, male patients' intonation variability remained relatively stable. F₀ variation in male and female patients with PD were significantly reduced compared with the control group in the first examination and the follow up as well. Progression of prosodic impairment over time showed no correlation to disease duration or UPDRS motor score. Some aspects of dysprosody in PD show characteristic changes over time, but show no clear correlation with general motor impairment as assessed by UPDRS motor score. Therefore, we suspect that the underlying mechanism could be independent from dopaminergic deficits. © 2008 Movement Disorder Society     

Voice quality of psychological origin

Variations in voice quality are essentially related to modifications of the glottal source parameters, such as: F0, jitter, and shimmer. Voice quality is affected by prosody, emotional state, and vocal pathologies. Psychogenic vocal pathology is particularly interesting. In the present case study, the speaker naturally presented a ventricular band voice whereas in a controlled production he was able to use a more normal phonation process. A small corpus was recorded which included sustained vowels and short sentences in both registers. A normal speaker was also recorded in similar tasks. Annotation and extraction of parameters were made using Praat's voice report function. Application of the Hoarseness Diagram to sustained productions situates this case in the pseudo-glottic phonation region. Analysis of several different parameters related to F0, jitter, shimmer, and harmonicity revealed that the speaker with psychogenic voice was capable of controlling certain parameters (e.g. F0 maximum) but was unable to correct others such as shimmer.     

Acoustic evaluation of short-term effects of repetitive transcranial magnetic stimulation on motor aspects of speech in Parkinson’s disease

Hypokinetic dysarthria in Parkinson’s disease (PD) can be characterized by monotony of pitch and loudness, reduced stress, variable rate, imprecise consonants, and a breathy and harsh voice. Using acoustic analysis, we studied the effects of high-frequency repetitive transcranial magnetic stimulation (rTMS) applied over the primary orofacial sensorimotor area (SM1) and the left dorsolateral prefrontal cortex (DLPFC) on motor aspects of voiced speech in PD. Twelve non-depressed and non-demented men with PD (mean age 64.58 ± 8.04 years, mean PD duration 10.75 ± 7.48 years) and 21 healthy age-matched men (a control group, mean age 64 ± 8.55 years) participated in the speech study. The PD patients underwent two sessions of 10 Hz rTMS over the dominant hemisphere with 2,250 stimuli/day in a random order: (1) over the SM1; (2) over the left DLPFC in the “on” motor state. Speech examination comprised the perceptual rating of global speech performance and an acoustic analysis based upon a standardized speech task. The Mann–Whitney U test was used to compare acoustic speech variables between controls and PD patients. The Wilcoxon test was used to compare data prior to and after each stimulation in the PD group. rTMS applied over the left SM1 was associated with a significant increase in harmonic-to-noise ratio and net speech rate in the sentence tasks. With respect to the vowel task results, increased median values and range of Teager-Kaiser energy operator, increased vowel space area, and significant jitter decrease were observed after the left SM1 stimulation. rTMS over the left DLPFC did not induce any significant effects. The positive results of acoustic analysis were not reflected in a subjective rating of speech performance quality as assessed by a speech therapist. Our pilot results indicate that one session of rTMS applied over the SM1 may lead to measurable improvement in voice quality and intensity and an increase in speech rate and tongue movements. Nevertheless, these changes were not accompanied by changes in a perceptual evaluation of speech performance by a speech therapist. Future placebo-controlled studies in larger patient cohorts should verify if rTMS would be clinically useful for treating hypokinetic dysarthria in PD.     

Relationship between acoustic measures and judgments of intelligibility in Parkinson’s disease: A within-speaker approach

This study investigated the acoustic basis of within-speaker, across-utterance variation in sentence intelligibility for 12 speakers with dysarthria secondary to Parkinson’s disease (PD). Acoustic measures were also obtained for 12 healthy controls for comparison to speakers with PD. Speakers read sentences using their typical speech style. Acoustic measures of speech rate, articulatory rate, fundamental frequency, sound pressure level and F2 interquartile range (F2 IQR) were obtained. A group of listeners judged sentence intelligibility using a computerized visual-analog scale. Relationships between judgments of intelligibility and acoustic measures were determined for individual speakers with PD. Relationships among acoustic measures were also quantified. Although considerable variability was noted, articulatory rate, fundamental frequency and F2 IQR were most frequently associated with within-speaker variation in sentence intelligibility. Results suggest that diversity among speakers with PD should be considered when interpreting results from group analyses.     

Voice quality of psychological origin

Variations in voice quality are essentially related to modifications of the glottal source parameters, such as: F₀, jitter, and shimmer. Voice quality is affected by prosody, emotional state, and vocal pathologies. Psychogenic vocal pathology is particularly interesting. In the present case study, the speaker naturally presented a ventricular band voice whereas in a controlled production he was able to use a more normal phonation process. A small corpus was recorded which included sustained vowels and short sentences in both registers. A normal speaker was also recorded in similar tasks. Annotation and extraction of parameters were made using Praat's voice report function. Application of the Hoarseness Diagram to sustained productions situates this case in the pseudo‐glottic phonation region. Analysis of several different parameters related to F₀, jitter, shimmer, and harmonicity revealed that the speaker with psychogenic voice was capable of controlling certain parameters (e.g. F₀ maximum) but was unable to correct others such as shimmer.     

Association of codon 167 Ser/Asn heterozygosity in the parkin gene with sporadic Parkinson's disease.

A variety of deletional and point mutations has been identified in the parkin gene on chromosome 6q25.2-27 in patients with autosomal recessive juvenile parkinsonism, a distinct form of familial Parkinson's disease (PD). To study the potential involvement of the parkin gene in development of non-hereditary idiopathic PD, a codon 167 serine/asparagine (167S/N) polymorphism located in its exon 4 was analyzed by direct sequencing in 71 patients with sporadic PD and 109 age-matched non-PD controls. The frequency of either 167S or 167N allele was not statistically different between PD patients and controls, while the frequency of 167S/N heterozygotes was significantly higher in PD patients (62.0% vs 45.9%), compared with that of both 167S/S and 167N/N homozygotes combined (chi2 4.467, p = 0.0346; odds ratio = 1.92, 95% confidence interval = 1.05-3.54). These observations suggest that the heterozygosity at codon 167 in the parkin gene might represent a genetic risk factor for development of sporadic PD.     

Polymorphism in the parkin gene in sporadic Parkinson's disease.

We report polymorphism of the parkin gene in 160 sporadic Parkinson's disease (PD) patients and controls. Three polymorphisms were found: a G-to-A transition in exon 4 (S/N167), a C-to-T transition in exon 10 (R/W366), and a G-to-C transition in exon 10 (V/L380). Genotype distributions and allele frequencies of S/N167 and V/L380 did not differ significantly between the two groups. The R/W366 allele frequency was significantly lower in PD patients (1.2 vs 4.4%). The level of protection from PD provided by this allele was 3.60 (95% CI; range, 0.45-6.50), suggesting that it may be a protective factor against PD.     

A longitudinal study of voice before and after phonosurgery for removal of a polyp

The aim of the present investigation was to evaluate the acoustic parameters, perceptual estimation, and self-estimation of voice before, 1 month after, and 6 years after surgical removal of a vocal fold polyp. Subjects were five male patients who came to the Phoniatric Clinic because of breathiness. For all patients, a polyp of one vocal fold was diagnosed. The operation was performed using cold instruments based on the principles of contemporary phonosurgery aiming maximally at preserving the phonatory bridge of the vocal fold. The subjects were recorded in a sound-proof booth three times: before surgery, 1 month post-, and 6 years post-operation. The patients read a short tale and they pronounced a sustained vowel /a/. The following variables were measured: clinical (the distance of the polyp from the anterior commissure, the width of the polyp base and the size of the polyp), and acoustic (F0, jitter, shimmer, harmonic-to-noise ratio, voice turbulence index, degree of voice breaks, and long-term average spectrum). Acoustic variables were measured using the program Praat, while the estimation of voice quality was completed using the GRBAS scale and self-estimation questionnaire of the voice quality, which were answered by the patients. The results showed significant improvement in the variables investigated and improved patients satisfaction with their vocal health after the surgery.     

N100 evoked potential latency variation and startle in schizophrenia

The contribution of evoked potential (EP) latency jitter, a measure of CNS temporal variability, on startle and EP gating defects in schizophrenic subjects has not been characterized. The amplitude of the N100/P200 EP complex (peak to trough) derived using a time-locked averaging procedure, N100 EP latency jitter derived from single trial analysis, acoustic startle response and clinical symptoms were measured in 51 schizophrenic subjects. N100 latency jitter was inversely correlated with N100/P200 EP amplitude in both cross-sectional and longitudinal analysis. Subjects with elevated EP gating ratios (>0.5) had similar latency jitter values for initial (S1) and test (S2) stimuli, while subjects with a low gating ratio (0-0.5) had a lower level of S1 latency jitter. Temporal variability thus plays a significant and complex role in previously reported sensory gating deficits in schizophrenic subjects.     

Voice and speech after laryngectomy

The aim of the investigation is to compare voice and speech quality in alaryngeal patients using esophageal speech (ESOP, eight subjects), electroacoustical speech aid (EACA, six subjects) and tracheoesophageal voice prosthesis (TEVP, three subjects). The subjects reading a short story were recorded in the sound-proof booth and the speech samples were acoustically analysed. Speech sound production was judged by 15 students of phonetics. The following variables were considered: (1) voice quality: fo, jitter, shimmer and harmonic-to-noise ratio, (2) speech sound production: number of recognized VCV syllables, and (3) temporal organization of speech: duration of the phonetic block, number of syllables in the phonetic block, rate of speech, rate of articulation and number of syllables in the longest phonetic block. The results showed that nearly normal air-stream source (lungs) in speech production of speakers with tracheoesophageal prosthesis significantly contributed to the speech timing and speech intelligibility of the alaryngeal speakers.     

A longitudinal study of voice before and after phonosurgery for removal of a polyp

The aim of the present investigation was to evaluate the acoustic parameters, perceptual estimation, and self‐estimation of voice before, 1 month after, and 6 years after surgical removal of a vocal fold polyp. Subjects were five male patients who came to the Phoniatric Clinic because of breathiness. For all patients, a polyp of one vocal fold was diagnosed. The operation was performed using cold instruments based on the principles of contemporary phonosurgery aiming maximally at preserving the phonatory bridge of the vocal fold. The subjects were recorded in a sound‐proof booth three times: before surgery, 1 month post‐, and 6 years post‐operation. The patients read a short tale and they pronounced a sustained vowel /a/. The following variables were measured: clinical (the distance of the polyp from the anterior commissure, the width of the polyp base and the size of the polyp), and acoustic (F0, jitter, shimmer, harmonic‐to‐noise ratio, voice turbulence index, degree of voice breaks, and long‐term average spectrum). Acoustic variables were measured using the program Praat, while the estimation of voice quality was completed using the GRBAS scale and self‐estimation questionnaire of the voice quality, which were answered by the patients. The results showed significant improvement in the variables investigated and improved patients satisfaction with their vocal health after the surgery.     

Evaluation of speech impairment in early stages of Parkinson’s disease: a prospective study with the role of pharmacotherapy

Despite the initial reports showing beneficial effects of dopaminergic treatment on speech in Parkinson’s disease (PD), more recent studies based upon valid measurements have not approved any improvement of speech performance under pharmacotherapy. The aim of this study was to analyze the effect of treatment initiation on the progression of speech impairment in PD, using novel evaluation criteria. Nineteen de novo patients with PD were tested and retested within 2 years after the introduction of antiparkinsonian therapy. As controls, 19 age-matched individuals were recorded. Speech examination included sustained phonation, fast syllable repetition, reading text, and monolog. Quantitative acoustic analyses of the key aspects of speech based on Gaussian kernel distribution, statistical decision-making theory, and healthy speech observation were used to assess the improvement or deterioration of speech. A trend for speech performances to improve was demonstrated after treatment mainly in quality of voice, intensity variability, pitch variability, and articulation. The treatment-related improvement differed in various aspects of speech for individual PD patients. Improvements in vowel articulation and pitch variability correlated with treatment-related changes in bradykinesia and rigidity, whereas voice quality and loudness variability improved independently. Using a novel approach of acoustic analysis and advanced statistics, improvements in speech performance can be demonstrated in PD patients after the introduction of antiparkinsonian therapy. Moreover, changes in speech articulation and pitch variability appear to be related with dopaminergic responsiveness of bradykinesia and rigidity. Therefore, speech may be a valuable marker of disease progression and treatment efficacy in PD.     

Characterizing the phenotypes of obstructive sleep apnea: Clinical,sleep, and autonomic features of obstructive sleep apnea with and without hypoxia

ObjectiveThe pathophysiological basis of obstructive sleep apnea (OSA) is not completely understood and likely varies among patients. In this regard, some patients with OSA do not exhibit hypoxemia. We aimed to analyze the clinical, sleep, and autonomic features of a group of patients with severe OSA without hypoxia (OSA−h) and compare to OSA patients with hypoxia (OSA+h) and controls.MethodsFifty-six patients with OSA−h, 64 patients with OSA+h, and 44 control subjects were studied. Clinical and sleep features were analyzed. Besides, time- and frequency-domain heart rate variability (HRV) measures comprising the mean R–R interval, the standard deviation of the RR intervals (SDNN), the low frequency (LF) oscillations, the high frequency (HF) oscillations, and the LF/HF ratio, were calculated across sleep stages during a one-night polysomnography.ResultsOSA−h patients had a lower body mass index, a lower waist circumference, lower apnea duration, and a higher frequency of previous naso-pharyngeal surgery when compared to OSA+h patients. In terms of heart rate variability, OSA+h had increased LF oscillations (i.e., baroreflex function) during N1–N2 and rapid eye movement (REM) sleep when compared to OSA−h and controls. Both OSA+h and OSA−h groups had decreased HF oscillations (i.e., vagal inputs) during N1–N2, N3 and REM sleep when compared to controls. The LF/HF ratio was increased during N1–N2 and REM sleep, only in patients with OSA+h.ConclusionsPatients with OSA−h exhibit distinctive clinical, sleep, and autonomic features when compared to OSA with hypoxia.SignificanceOSA is a heterogeneous entity. These differences must be taken into account in future studies when analyzing therapeutic approaches for sleep apnea patients.     

Parkin 基因多态性与散发性帕金森病关系的研究

目的探讨Parkin基因S/N 167多态性与散发性帕金森病(PD)的遗传易感性之间的关系.方法以120例散发性PD患者为研究对象,分为早发性PD组和晚发性PD组,120名正常人作为对照.采用聚合酶链式反应(PCR)扩增所需DNA片段,用限制性内切酶酶切技术测定所研究对象的基因型和等位基因.比较各组间基因型及等位基因频率的差异.结果 PD组与对照组S/N 167多态性等位基因频率无显著性差异(P>0.05);早发性PD组S/N 167多态性等位基因频率显著高于对照组和晚发性PD组(均P<0.05).结论Parkin基因S/N 167多态性可能是早发性PD的危险因素,其患PD的危险性较对照组增高1.69倍.     

Acoustic analysis of prosody in females with Parkinson's disease: comparison with normal controls

BACKGROUND: Voice abnormalities, collectively labeled as hypokinetic dysarthria, have been well characterized and occur in 90% of Parkinson's disease (PD) patients. However, studies of speech in PD, particularly of patients whose native language is other than English, are rarely found. The aim of this study is to compare the prosodic features of the speech of female PD patients and gender- and age-matched controls using acoustic analysis. METHOD: We have studied 8 PD female patients (68.4 +/- 6.4 years) and 8 female controls (63.5 +/- 6.8 years). The PD patients (H-Y stage 2, one subject; stage 2.5, four patients; stage 3, three patients), although treated with L-dopa, were examined when off. The fundamental frequency (Fo), intensity and duration of the speech were analysed with the software WinPitch 1.8 (Philippe Martin). The analysed Fo parameters were: usual Fo (Fo us), maximal Fo (Fo max), minimal Fo (Fo min), Fo max of the prenuclear tonic (Fo max PNT), Fo min of the prenuclear tonic (Fo min PNT), Fo max of the nuclear tonic (Fo max NT), Fo min of the nuclear tonic (Fo min TN), velocity of melodic variation of the PNT (VPNT), velocity of melodic variation of the NT (VNT), amplitude of melodic variation of the PNT (APNT), and amplitude of melodic variation of the NT (ANT). Duration of the statement (D), duration of the PNT (DPNT), duration of the NT (DNT) and number of syllables per second (NSS) were the duration parameters investigated. The following intensity variables were studied: mean intensity (MI), maximal intensity (I max), minimal intensity (I min), intensity of the PNT (IPNT) and intensity of the NT (INT). Differences were statistically significant if p<0.05. RESULTS: PD patients had significantly lower Fo max (232.1 +/- 32.9 Hz), lower Fo max PNT (168.5 +/- 83.5 Hz), lower Fo max NT (182.1 +/- 29.5 Hz), lower VNT (0.2 +/- 0.1 Hz), smaller APNT (20.4 +/- 12.1 Hz), smaller ANT (26 +/- 12.6 Hz), smaller NSS (4.8 +/- 0.1), higher IM (32.7 +/- 5.6 dB), higher I max (37.1 +/- 2.9 dB), higher I min (23.2 +/- 6.1 dB) and higher IPNT (35.4 +/- 2.9 dB) than controls (respectively: 248.7 +/- 23.9 Hz, 216.4 +/- 25.6 Hz, 197.5 +/- 35.8 Hz, 0.3 +/- 0.2 Hz, 22.7 +/- 15.9 Hz, 36.3 +/- 21.8 Hz, 5.3 +/- 0.8, 30.4 +/- 6.1 dB, 20.2 +/- 6.6 dB, 33.1 +/- 2.9 dB, and 30.9 +/- 4.3 dB. CONCLUSION: In comparison with controls, Brazilian female PD patients have a slower speech characterized by a narrow range of Fo variation (which likely accounts for the poor vocal tessitura of parkinsonian speech) and higher intensity. The latter is consistent with a compensatory attempt to overcome the latter.     

Exercise test in Parkinson's disease

In this study we assessed cardiovascular performance and metabolic response after an exercise test in Parkinsonian patients (PD patients). Methods: 15 PD patients (10 male, 5 female; mean age;63±6.17 y; mean weight: 72.2±9.5 kg) and 15 sex, age (mean: 63.8±5.38 y), and weight-(mean: 72.2±8.69 kg) matched controls performed an exercise test using a cycle ergometer and a ramp protocol. All patients and control subjects underwent a heart rate variability test prior to the exercise test. At rest and at the end of each interval blood pressure (BP) and capillary lactate samples were taken. Heart rate was monitored continuously. Results: The heart rate variability tests were abnormal in Parkinson's patients. All patients and control subjects achieved an intensity level of 75 watts, 12/15 PD patients managed 100 watts, and 7/15 PD patients managed 150 watts. 12/15 control subjects performed at an intensity level of 125 Watts and 9/15 at an intensity level of 150 Watts. There was no statistically significant difference in heart rate increase but there was a tendency to lower lactate levels at high intensity levels in PD patients. PD patients had a statistically lower systolic BP at 75, 100, 125, and 150 watts. Conclusion: We did not find striking differences in cardiovascular adaptation to physical work in PD patients and we propose, therefore, that it should be possible to improve cardiovascular endurance in PD patients. Previously, reports have suggested respiratory chain impairment in Parkinson's disease and poor endurance performance. However, our results do not support a clinically relevant impairment of the respiratory chain.     

Cardiac autonomic impairment during sleep is linked with disease severity in Parkinson’s disease

ObjectiveCardiac physiology during sleep in Parkinson’s disease (PD) remains poorly explored. We studied heart rate variability (HRV) across sleep stages in PD patients and correlated the results with clinical features.MethodsCross-sectional study comprising 33 patients with PD and 29 controls matched for age, gender, and number of apneas/hypopneas per hour. HRV measures, (mean R–R interval, SDNN, ULF, VLF, LF, HF and LF/HF) were calculated separately for all sleep stages as well as wakefulness just before and after sleep during one-night polysomnography. Correlation analysis was performed between HRV values and PD patients’ characteristics.ResultsThe mean R–R interval was lower in all sleep stages in PD patients when compared with controls. VLF and LF were lower during REM sleep in PD patients. HF during N1–N2 stage was higher in PD. We found inverse correlations between VLF and LF during REM sleep and UPDRS-ON and UPDRS-OFF.ConclusionVLF and LF during REM sleep might constitute surrogate markers of disease severity.SignificanceThese findings provide additional clinical evidence of the autonomic impairment commonly observed in PD, and prove that cardiac autonomic dysfunction during REM sleep is correlated with disease severity.