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 Parkinson's 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.

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

Pathophysiology and Treatment of Muscle Tension Dysphonia: A Review of the Current Knowledge

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 Parkinson's disease. Thirty-five patients with idiopathic Parkinson's 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 Parkinson's disease compared with a placebo speech treatment group.

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

That the human left and right cerebral hemispheres perform different functions is widely accepted; but there is little evidence of whether or not similar functional asymmetries exist in non-human vertebrates. In this paper, neuro-anatomical similarities between human and other vertebrate brains are considered, and data concerning physical asymmetries reviewed. The defining features of human lateralization are taken to be right-handedness, as a skewed but continuous distribution of preferences, and a greater involvement of the left hemisphere in species-specific vocalization, with right-hemisphere superiority in spatial perception and emotionality less well-marked characteristics. Rodents, cats, at least one species of marsupial, and macaque monkeys have consistent hand preferences for food reaching. These may result from constitutional factors, but in every species studied the distribution of preferences is unskewed. Canaries appear to have left-hemisphere dominance of vocal production, and there is limited support for the conjecture that macaque monkeys have left-hemisphere dominance for reception of species-specific cries, and/or for short-term auditory memory. Left and right unilateral hemispheric damage may have appreciably different effects on emotionality in rats, sound localization in cats, and tactile discrimination in monkeys, although the available evidence is equivocal. It seems possible that asymmetries of cerebral function are widespread in vertebrates. In particular, left hemisphere dominance of species-specific communication might be common in birds and primates: left-hemisphere dominance of human speech may be an example of a general vertebrate tendency towards unilateral control of vocalization.

Edith Whetnall

Papers

The Voice and its Disorders.