Effects of Parkinson’s disease in the musical domain
Parkinson’s disease is accompanied by symptoms such as tremor, rigidity and bradykinesia (slow movements). Speech is often affected as well, concerning the variation in pitch, intensity and rhythm. It is often assumed that these abnormalities can be especially related to a stiffness of the vocal cords, but various studies suggest that patients also have a decreased sensitivity for the emotional meaning of speech. They demonstrate speech problems which are cognitive by nature.
Parkinson and music
In healthy people music inspires to moving, clapping or singing along. And in patients with Parkinson’s disease the effect of music can be beneficial as well: while listening to music they experience a diminishing of ‘freezing of gait’ (sudden inability to walk well) and show a more fluent pattern of movement.
There are several studies that indicate a part overlap between the neural processing of music and language. On the one hand it is known that people who have a serious stammer can often sing without any problems. And often, after a stroke, patients can no longer speak, but they can sing.
If speech impediments of patients with Parkinson’s disease are not just the result of a stiffening of the muscles, but of higher cognitive processes connected to speech, then it may be possible that the musical domain is relatively unaffected.
In this research patients with Parkinson’s disease who generally sing, hum or whistle in daily life, will be asked as test patients. Researcher Robert Harris is visiting participants in their homes to make recordings of their speaking and singing voice during the performance of various tasks. The recordings are being analysed to determine whether Parkinson patients’ singing differs from that of healthy people.
This group of patients will be compared to a group of healthy volunteers, matched by age. Patients with Parkinson’s disease will a.o. be recruited among the visitors of the Outpatient Clinic for Neurology and among patient associations.
Aim of the research
One of the characteristics of the speech of these patients is a lack of prosodic variation (in rhythm, emphasis and intonation). The purpose of this study is to determine whether the singing of Parkinson patients can be characterized bij a similar lack of melodic variation. If not, it might conceivably be possible to develop new therapies for speech improvement, based on transfer from the music to the speech domain, similar to Melodic Intonation Therapy for aphasia.
First the normal speech of the test person will be recorded. After this they will be asked to recite the text of a well-known song in the rhythm of the song and then to hum or whistle the melody. Finally, they will be asked to ‘improvise’ a melody either humming or whistling. The researcher invites this by humming or whistling the first line of the melody himself, after which the test person continues according to his own preference.
During the research sound recordings will be made. The analysis of the recordings will be focused on:
- Pace of speech during the recital of lyrics in the rhythm of the song
- Difference in pitch of humming and whistling of a well-known song by the test person, compared to the original pitch of the song
- Aberrations in the exact intervals of the song during humming or whistling
- Size, rhythmic variation and length of intervals in the improvised finishing of brief melodic fragments
This study is conducted according to the principles of the Declaration of Helsinki (accepted by the 59th General Meeting of the WMA, Seoul, October 2008) and in agreement with the Medial Research Involving Human Subjects Act (WMO, 1 December 1999). Permission has been granted by the Medical Ethic Testing Committee Groningen. Data collecting commenced in February 2012.
- Drs. R. Harris, Prince Claus Conservatoire, Research School of Behavioural and Cognitive Neurosciences, University of Groningen
- Dr. B.M. de Jong, Neurology, University Medical Centre Groningen (UMCG)