Voice change in parkinsonism and its management

Introduction:

Voice gets commonly affected in patients with parkinsonism. These patients have soft breathy monotone voice. This voice is usually perceived by the patient as normal loudness. This is usually caused by poor effort from the bellows mechanism (bradikinetic). The chest wall and diaphragmatic movements are also poor. In addition to this problem these patients also have inaccurate perception of their personal speech effort.

These patients also have additional problems. They include:

1. vocal tremor

2. Poor articulation

3. Stuttering quality of speech

4. Difficulty in initiating speech

5. Swallowing difficulties

Major features contributing to voice disorders in these patients include:

1. Global scale down of neural drive to speech mechanism (bradykinesia) 2. Inaccurate sensory perception of self effort involved in vocalization. This prevents the individual from accurately monitoring vocal output. 3. Difficulty with independently generating the correct effort to produce adequate vocalization

Indirect laryngoscopy:

Findings include:

1. Bowing of vocal folds

2. Slow vibration of vocal folds on phonation

3. Pooling of saliva

4. Decreased pharyngeal secretions

5. Diminished cough reflex and aspiration

Management:

Vocal fold augmentation / medialization procedures may improve loudness of sound in these patients. For this improvement to occur sufficient respiratory drive for phonation should exist. These laryngeal surgical procedures donot improve articulation.

Deep brain stimulation which is known to improve limb movements has no role of speech improvement in these patients.

Lee Silverman Voice Therapy:

This programming helps in improving the speech in these patients. This programme works by: 1. Improving the physical efforts of the patient 2. By resetting their sensory perception of their own vocal output. 3. Swallowing function also shows improvement in these patients

Concept of this therapy:

1. Increasing the amplitude of phonatory output (think loud, and speak loud)

2. Improving sensory perception of effort (think loud)

3. Administering treatment in high effort style

4. Administering treatment intensively (3-4 times a week 16 sessions in a month)

5. Quantifying all speech and voice output (sound meter)