Objective: To determine the rate of functional decline in a large cohort of patients with Huntington’s disease (HD) followed at 43 sites by the Huntington Study Group (HSG). Methods: The annual rate of functional decline was measured using the Total Functional Capacity Scale (TFC) and the Independence Scale (IS) in 960 patients with definite HD followed prospectively for a mean of 18.3 months. All patients were rated with the Unified Huntington’s Disease Rating Scale (UHDRS). Sample size calculations for hypothetical clinical trials were calculated. Results: A factor analysis of the UHDRS at baseline yielded 15 factors accounting for 77% of the variance. The TFC score declined at a rate of 0.72 units/year (standard error [SE] 0.04) and the IS score declined at a rate of 4.52 units/year (SE 0.23). Lower TFC score at baseline, indicating more severe impairment, was associated with less rapid annual decline in TFC score, perhaps reflecting the floor effect of the scale. The annual rate of decline for 575 patients with baseline TFC scores of 7 to 13 was 0.97 (SE 0.06), was 0.38 (SE 0.08) for 270 patients with baseline TFC scores of 3 to 6, and was 0.06 (SE 0.1) for 101 patients with TFC scores of 0 to 2. In multivariate analysis (n = 960), longer disease duration and better cognitive status at baseline were associated with a less rapid rate of decline in TFC score, whereas depressive symptomatology was the only factor associated with more rapid decline on the IS score. Age at onset of HD, sex, weight, and education did not affect decline on either score. Conclusions: The comparable rates of decline on the TFC and the IS scores with other published studies suggest that these estimates of functional decline are representative of HD patients who are evaluated at HSG research sites. In longitudinal analysis, longer disease duration and better neuropsychological performance at baseline were associated with a less rapid rate of decline in TFC score, whereas depressive symptomatology at baseline was associated with a more rapid decline in the IS score. These rates of functional decline and the covariates that modify them should be considered in estimating statistical power and designing future therapeutic trials involving HD patients with early or moderately severe disease.

Rate of functional decline in Huntington’s disease

Dysarthria in Parkinson's disease can be characterised by monotony of pitch and loudness, reduced stress, variable rate, imprecise consonants, and a breathy and harsh voice. Use of levodopa to replenish dopamine concentrations in the striatum seems to improve articulation, voice quality, and pitch variation, although some studies show no change in phonatory parameters. Traditional speech therapy can lead to improvement of dysarthria, and intensive programmes have had substantial beneficial effects on vocal loudness. Unilateral surgical lesions of subcortical structures are variably effective for the alleviation of dysarthria, whereas bilateral procedures typically lead to worsening of speech production. Among deep-brain stimulation procedures, only stimulation of the subthalamic nucleus improves some motor components of speech although intelligibility seems to decrease after surgery. Due to the variable treatment effects on parkinsonian speech, management of dysarthria is still challenging for the clinician and should be discussed with the patient.

https://www.thelancet.com/pdfs/journals/laneur/PIIS1474-4422(04)00854-3.pdf

Treatments for dysarthria in Parkinson's disease

Researchers estimate that 89% of people with Parkinson's disease (PD) have a speech or voice disorder including disorders of laryngeal, respiratory, and articulatory function. Despite the high incidence of speech and voice impairment, studies suggest that only 3-4% of people with PD receive speech treatment. The authors review the literature on the characteristics and features of speech and voice disorders in people with PD, the types of treatment techniques available, including medical, surgical, and behavioral therapies, and provide recommendations for the current efficacy of treatment interventions and directions of future research.

/pdf/speech-treatment-for-parkinson-s-disease-40ce54hfu9.pdf

Speech treatment for Parkinson's disease.

Effects of speech therapy and pharmacologic and surgical treatments on voice and speech in Parkinson's disease: a review of the literature.

Researchers estimate that 89% of people with Parkinson's disease (PD) have speech and voice disorders including disorders of laryngeal, respiratory and articulatory function. Despite the high incidence of speech and voice impairment, studies suggest that only 3-4% of people with PD receive speech treatment. Here, we review the literature on the characteristics and features of speech and voice disorders in people with PD and the types of treatment techniques available (medical, surgical and behavioral), with a focus on behavioral therapies. We provide a summary of the current status of the field of speech treatment in PD and recommendations for implementation of the current efficacy of treatment interventions. Directions for future research, including a speculative viewpoint on how the field will evolve in 5 years time, are discussed.

The articulatory function of the labial musculature has been investigated electromyographically before and after treatment with l-dopa in patients with Parkinsonism who had dysarthria. Before medication the EMG traces generally showed a constant, abnormally increased, tonic activity, together with disturbed reciprocal innervation, which impaired the articulatory activity. After medication the tonic hyperactivity was reduced and the reciprocal innervation re-established. This normalization of the EMG articulatory pattern was paralleled by an improvement of the dysarthria.

https://jnnp.bmj.com/content/jnnp/34/6/679.full.pdf

A. Persson

Papers

Effect of l-dopa on speech in Parkinsonism : An EMG study of labial articulatory function