In a study by Kleinow. et. al, in 2001, about 75 -100% of patients with Parkinson's disease develop speech and voice problems. Significant respiratory difficulties and bowed vocal chords have been cited as causes of these voice symptoms. Boone and MacFarlane described these speech and voice changes as hypokinetic dysarthria characterized as reduced loudness, breathy voice, monotonous pitch, intermittent rapid rushes of speech and soft production of consonants.
Based on the above observations, the most effective approach to voice therapy has been to exaggerate one component of speech to improve all other components like loudness, voice, quality, pitch, and rate. All these components have been formalized into the LSVT (Lee Silverman Voice Treatment).
The LSVT program is the first speech therapy program supported by short and long-term efficacy studies that document increased functional communication. The researches have been funded by the National Institutes of Health and the National Institute for Deafness and other Communication Disorders (NIDCD) in the United States of America.
The three components of the LSVT program are the following:
1. Enhancing the vocal source (adduction)
2. Using phonation as a trigger to increase effort and coordination through stimulating the “loud” global variable (respiratory support)
3. Retraining sensory processing during the speech production (increasing fundamental frequency range)
LSVT also involves a 1 hour therapy sessions/4 times a week/1month so that a patient receives 13-16 hours of individual therapy.
The 5 essential concepts of the LSVT program are as follows:
1. Voice
A. Improving vocal fold adduction
B. Maximum impact on intelligibility
C. Immediate reinforcement
D. “THINK LOUD / THINK SHOUT”
2. High Effort
A. Patient Rationale
Overrides rigidity and hypokinesia by pushing patients to new effort levels
Trains new target by putting the “load on the larynx”
Dealing with a progressive neurological disease
B. Clinician Rationale
Clinician effort equals patient effort
Lack of affect and physical condition of patient
Tendency to be reactive
3.Intensive Treatment
A. Daily opportunity to practice increases the chance of “building daily increments of vocal effort”
B. Maintain motivation and accountability
C. Maximize habituation and carry over
D. Provides an opportunity for clinician to see patient’s daily fluctuations
4.Calibration
A. The patient knows and accepts the amount of effort needed to consistently increase loudness that is within normal limits so he will use louder voice automatically
B. Problem scaling amplitude of motor output related to voice
C. Need to have “knowledge of results”
D. Convince patient that loud/strong voice is within normal limits
E.Habituation and carryover
5.Quantification
A. The key to motivate patient and provide feedback
B. Objective methods to document improvement
C. Precious speech treatment Ineffective/document efficacy
D. Reimbursement/referrals/ethics
The hierarchy of activities or the speech production tasks would progress from words in week 1 to phrases in week 2 to reading aloud in week 3 and finally, conversation in week 4.
The limitations of LSVT are as follows:
A. Treatment dosage may not be possible for those with
(1) physical limitations,
(2) geographic barriers,
(3) or financial reasons
B. Trained and certified clinicians are not available across the country
C. Lack of consistent insurance reimbursement may be an obstacle
Presently, only 3-4% of those with Parkinson disease receive speech treatment
References:
1. Boone, B.R. &McFarlane, S.C. (2000). The Voice and Voice Therapy (6th ed.). Needham Heights, MA: Ally & Bacon.
2.Kleinow, J., Smith, A., Ramig, L.O. (2001). Speech motor stability in IPD: effects of rate and loudness manipulations. Journal of Speech, Language, and Hearing Research, 44, 1041-51.
3. National Parkinson Foundation. (n.d.). Speech and voice problems in individuals with Parkinson disease. Retrieved March 30, 2003 from http://www.parkinson.org/voice.htm
