Generative music processes in Parkinson's disease: facilitation of motor behavior by internally generated stimuli.

Prosodic anomalies in the speech of patients suffering from Parkinson's disease
(PD) are generally attributed to rigidity and brady- and hypokinesia,
especially of the laryngeal musculature. However, the inability of patients to
recognize or produce prosodic distinction between questions and statements
points at impairment of higher cognitive function implicated in language.
Recently, a similar inability of congenital amusics to recognize prosodic
distinction has been demonstrated, suggesting that musical pitch discrimination
and prosodic discrimination in speech are interrelated.

Musical stimuli are known to facilitate motor behavior such as gait in PD.
Similarly, one could expect music to facilitate other forms of motor behavior,
for example speech. Indeed, singing and rhythmic tapping have been used to
facilitate speech in the treatment of expressive aphasia (Melodic Intonation
Therapy). In the first case, music functions as an external cue, in the second
as an internal cue.

If in PD, as in expressive aphasia, the impairment of verbal expression is
restricted to the language domain, generative music ability might remain
intact. In that case, whistling a familiar or improvised tune might still
reveal regularity of pitch level and a normal statistical distribution of scale
tones. The possible dissociation of speech and music production in PD patients
would provide insight into the role of music as an internally generated
stimulus in cerebral motor control. Alternatively, if such dissociation cannot
be demonstrated, one may infer the existence of a common musical-linguistic
neuronal source.

Obtaining fundamental insight into sensorimotor integration in Parkinson's
disease, targeted on (i) the relationship between cognitive deficits and
prosodic anomalies, and (ii) the effect of music on the motor aspects of speech
production.

PD patients and healthy controls will be given the following tasks:
1. State overlearned autobiographic data such as name, address, place of
residence, date of birth and birthplace in a normal
speaking voice.
2. Recite the lyrics of a familiar tune, speaking in the rhythm of the song.
3. Sing the song with lyrics.
4. Hum or whistle the melody of a familiar theme from radio or
CD
5. Hum or whistle a continuation to the interrupted phrase of an unfamiliar
melody.

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