Lorraine O. Ramig

Suitability of Dysphonia Measurements for Telemonitoring of Parkinson's Disease

In this paper, we present an assessment of the practical value of existing traditional and nonstandard measures for discriminating healthy people from people with Parkinsons disease (PD) by detecting dysphonia. We introduce a new measure of dysphonia, pitch period entropy (PPE), which is robust to many uncontrollable confounding effects including noisy acoustic environments and normal, healthy variations in voice frequency. We collected sustained phonations from 31 people, 23 with PD. We then selected ten highly uncorrelated measures, and an exhaustive search of all possible combinations of these measures finds four that in combination lead to overall correct classification performance of 91.4%, using a kernel support vector machine. In conclusion, we find that nonstandard methods in combination with traditional harmonics-to-noise ratios are best able to separate healthy from PD subjects. The selected nonstandard methods are robust to many uncontrollable variations in acoustic environment and individual subjects, and are thus well suited to telemonitoring applications.

Intensive voice treatment (LSVT®) for patients with Parkinson's disease: a 2 year follow up

OBJECTIVES To assess long term (24 months) effects of the Lee Silverman voice treatment (LSVT®), a method designed to improve vocal function in patients with Parkinsons disease. METHODS Thirty three patients with idiopathic Parkinsons disease were stratified and randomly assigned to two treatment groups. One group received the LSVT®, which emphasises high phonatory-respiratory effort. The other group received respiratory therapy (RET), which emphasises high respiratory effort alone. Patients in both treatment groups sustained vowel phonation, read a passage, and produced a monologue under identical conditions before, immediately after, and 24 months after speech treatment. Change in vocal function was measured by means of acoustic analyses of voice loudness (measured as sound pressure level, or SPL) and inflection in voice fundamental frequency (measured in terms of semitone standard deviation, or STSD). RESULTS The LSVT® was significantly more effective than the RET in improving (increasing) SPL and STSD immediately post-treatment and maintaining those improvements at 2 year follow up. CONCLUSIONS The findings provide evidence for the efficacy of the LSVT® as well as the long term maintenance of these effects in the treatment of voice and speech disorders in patients with idiopathic Parkinsons disease.

Changes in vocal loudness following intensive voice treatment (LSVT®) in individuals with Parkinson's disease: A comparison with untreated patients and normal age-matched controls

This study assessed the impact of the Lee Silverman Voice Treatment (LSVT®) on vocal loudness [sound pressure level (SPL)] in a group of dysarthric individuals with idiopathic Parkinsons disease (IPD). Pre‐ to post‐treatment changes in SPL in the treated group were compared with changes in voice SPL during the same time in two control groups: individuals with IPD not treated with the LSVT® and in non‐disordered individuals, age‐matched to the patients. All subjects produced the same voice and speech tasks—sustaining vowel phonation, reading the “Rainbow Passage,” producing a short monologue, and describing a picture. These tasks were recorded at three different occasions: just prior to treatment, just after treatment, and 6 months following treatment. The individuals treated with LSVT® increased voice SPL from baseline to post‐treatment by an average of 8 dB and from baseline to 6 months follow‐up by an average of 6 dB. These changes were statistically significant and perceptibly audible. No significant changes in SPL were observed in the control groups during the time corresponding to the treatment and follow‐up. Differences in SPL between the treated and untreated patients at post‐treatment and follow‐up were statistically significant for all voice and speech tasks. These findings, along with others, provide additional support for the efficacy of the LSVT®. Mov. Disord. 16:79–83, 2001.

Swallowing and voice effects of Lee Silverman Voice Treatment (LSVT®): a pilot study

Objective: To define the effects of Lee Silverman Voice Treatment (LSVT® on swallowing and voice in eight patients with idiopathic Parkinsons disease. Methods: Each patient received a modified barium swallow (MBS) in addition to voice recording before and after 1 month of LSVT®. Swallowing motility disorders were defined and temporal measures of the swallow were completed from the MBS. Voice evaluation included measures of vocal intensity, fundamental frequency, and the patients perception of speech change. Results: before LSVT®, the most prevalent swallowing motility disorders were oral phase problems including reduced tongue control and strength. Reduced tongue base retraction resulting in residue in the vallecula was the most common disorder in the pharyngeal stage of the swallow. Oral transit time (OTT) and pharyngeal transit time (PTT) were prolonged. After LSVT®, there was an overall 51% reduction in the number of swallowing motility disorders. Some temporal measures of swallowing were also significantly reduced as was the approximate amount of oral residue after 3 ml and 5 ml liquid swallows. Voice changes after LSVT® included a significant increase in vocal intensity during sustained vowel phonation as well as during reading. Conclusions: LSVT® seemingly improved neuromuscular control of the entire upper aerodigestive tract, improving oral tongue and tongue base function during the oral and pharyngeal phases of swallowing as well as improving vocal intensity.

Intensive speech treatment for patients with Parkinson's disease Short- and long-term comparison of two techniques

The purpose of this study was to evaluate the long-term (12 months) effects of two forms of speech treatment on the speech and voice deficits that occur in Parkinsons disease. Thirty-five patients with idiopathic Parkinsons disease were assigned to one of two speech treatment groups: voice and respiration (The Lee Silverman Voice Treatment [LSVT]) or placebo (respiration) treatment. Vocal intensity data from before, immediately after, and at 6 and 12 months after speech treatment revealed statistically significant differences between the treatment groups. Only subjects in the LSVT group improved or maintained vocal intensity above pretreatment levels by 12 months after treatment. The placebo group had statistically significant deterioration of vocal intensity levels from before to 12 months after treatment during conversational monologue. The LSVT group did not deteriorate to levels below pretreatment in vocal intensity over the 12-month period. This study is the first to document the short- and long-term effects of intensive speech treatment (LSVT), which focuses on the voice, for patients with Parkinsons disease compared with a placebo speech treatment group. NEUROLOGY 1996;47: 1496-1504

Novel Speech Signal Processing Algorithms for High-Accuracy Classification of Parkinson's Disease

There has been considerable recent research into the connection between Parkinsons disease (PD) and speech impairment. Recently, a wide range of speech signal processing algorithms (dysphonia measures) aiming to predict PD symptom severity using speech signals have been introduced. In this paper, we test how accurately these novel algorithms can be used to discriminate PD subjects from healthy controls. In total, we compute 132 dysphonia measures from sustained vowels. Then, we select four parsimonious subsets of these dysphonia measures using four feature selection algorithms, and map these feature subsets to a binary classification response using two statistical classifiers: random forests and support vector machines. We use an existing database consisting of 263 samples from 43 subjects, and demonstrate that these new dysphonia measures can outperform state-of-the-art results, reaching almost 99% overall classification accuracy using only ten dysphonia features. We find that some of the recently proposed dysphonia measures complement existing algorithms in maximizing the ability of the classifiers to discriminate healthy controls from PD subjects. We see these results as an important step toward noninvasive diagnostic decision support in PD.

Thyroarytenoid muscle activity associated with hypophonia in Parkinson disease and aging

Objective: To compare electromyographic (EMG) amplitudes of the thyroarytenoid (TA) muscle in young and older individuals and individuals with idiopathic PD (IPD) under conditions of known vocal loudness (sound pressure level). Background: Voice disorders frequently accompany aging and IPD, but it is unclear how laryngeal muscle physiology is affected by these processes and how changes in laryngeal muscle activity result in characteristic changes of the voice. Methods: Absolute and relative (to maximum) EMG amplitudes of the TA muscle were compared during speech and nonspeech tasks. Corresponding sound pressure (SPL) measures were obtained for the speech tasks. Results: Absolute TA amplitudes were consistently the highest in the young individuals, lowest in the individuals with IPD, and intermediate in the older individuals. Relative TA amplitudes were generally the highest for the young individuals, lowest for the older individuals, and intermediate for the individuals with IPD. SPL findings showed the older individuals and individuals with IPD produced most of the speech tasks with comparable SPLs, and these levels were consistently lower than those of the young individuals. Conclusions: Reduced levels of TA muscle activity may contribute to the characteristic hyophonic voice disorders that frequently accompany IPD and aging.

Vocal Sound Pressure Level and Self-Perception of Speech and Voice in Men and Women With Idiopathic Parkinson Disease

This study compared vocal sound pressure level (SPL) and self-perception of speech and voice in men and women with idiopathic Parkinson disease (PD) and in healthy men and women. Thirty subjects wi...

The Aging Voice: A Review, Treatment Data and Familial and Genetic Perspectives

This paper will provide a review of aspects of vocal aging within the context of general body aging and describe two data sets related to the aging voice. Data will be presented which document pre- to posttreatment improvement in select voice characteristics (sound pressure level, subglottal air pressure, thyroarytenoid laryngeal muscle activity and voice quality) following application of an intensive voice treatment program (the LSVT®) to 3 individuals with aged voice. Additionally, physiological data (forced expiratory volume, visual accommodation, bone density, taste discrimination, white blood count and resting heart rate) and select perceptual (perceived age) and acoustic measures (reflecting both cycle-to-cycle and longer-term intensity and frequency stability) from 67 subjects will be reviewed from the work of Gray and colleagues to document the differential impact of the global aging process across organ systems including the aging voice.

Testing objective measures of motor impairment in early Parkinson's disease: Feasibility study of an at-home testing device.

We tested the feasibility of a computer based at‐home testing device (AHTD) in early‐stage, unmedicated Parkinsons disease (PD) patients over 6 months. We measured compliance, technical reliability, and patient satisfaction to weekly assessments of tremor, small and large muscle bradykinesia, speech, reaction/movement times, and complex motor control. relative to the UPDRS motor score. The AHTD is a 6.5″ × 10″ computerized assessment battery. Data are stored on a USB memory stick and sent by internet to a central data repository as encrypted data packets. Although not designed or powered to measure change, the study collected data to observe patterns relative to UPDRS motor scores. Fifty‐two PD patients enrolled, and 50 completed the 6 month trial, 48 remaining without medication. Patients complied with 90.6% of weekly 30‐minute assessments, and 98.5% of data packets were successfully transmitted and decrypted. On a 100‐point scale, patient satisfaction with the program at study end was 87.2 (range: 80–100). UPDRS motor scores significantly worsened over 6 months, and trends for worsening over time occurred for alternating finger taps (P = 0.08), tremor (P = 0.06) and speech (P = 0.11). Change in tremor was a significant predictor of change in UPDRS (P = 0.047) and was detected in the first month of the study. This new computer‐based technology offers a feasible format for assessing PD‐related impairment from home. The high patient compliance and satisfaction suggest the feasibility of its incorporation into larger clinical trials, especially when travel is difficult and early changes or frequent data collection are considered important to document.