OBJECTIVES: The effect of rhythmic auditory stimulation (RAS) on gait velocity, cadence, stride length, and symmetry was studied in 31 patients with idiopathic Parkinson's disease, 21 of them on (ON) and 10 off medication (OFF), and 10 healthy elderly subjects. METHOD: Patients walked under four conditions: (1) their own maximal speed without external rhythm; (2) with the RAS beat frequency matching the baseline cadence; (3) with RAS 10% faster than the baseline cadence; (4) without rhythm to check for carry over from RAS. Gait data were recorded via a computerised foot switch system. The RAS was delivered via a 50 ms square wave tone embedded in instrumental music (Renaissance style) in 2/4 metre prerecorded digitally on a sequencer for variable tempo reproduction. Patients on medication were tested in the morning 60-90 minutes after medication. Patients off medication were tested at the same time of day 24 hours after the last dose. Healthy elderly subjects were tested during the same time of day. RESULTS: Faster RAS produced significant improvement (P < 0.05) in mean gait velocity, cadence, and stride length in all groups. Close synchronisation between rhythm and step frequency in the controls and both Parkinson's disease groups suggest evidence for rhythmic entrainment mechanisms even in the presence of basal ganglia dysfunction. CONCLUSIONS: The results are consistent with and extend prior reports of rhythmic auditory facilitation in Parkinson's disease gait when there is mild to moderate impairment, and suggest a technique for gait rehabilitation in Parkinson's disease.

https://jnnp.bmj.com/content/jnnp/62/1/22.full.pdf

Rhythmic auditory-motor facilitation of gait patterns in patients with Parkinson's disease.

This study investigated the role of the basal ganglia in timing operations. Nondemented, medicated Parkinson's disease (PD) patients and controls were tested on 2 motor-timing tasks (paced finger tapping at a 300- or 600-ms target interval), 2 time perception tasks (duration perception wherein the interval between the standard tone pair was 300 or 600 ms), and 2 tasks that controlled for the auditory processing (frequency perception) demands of the time perception task and the movement rate (rapid tapping) in the motor-timing task. Using A.M. Wing and A.B. Kristofferson's (1973) model, the total variability in motor timing was partitioned into a clock component, which reflects central timekeeping operations, and a motor delay component, which estimates random variability due to response implementation processes. The PD group was impaired at both target intervals of the time perception and motor-timing tasks. Impaired motor timing was due to elevated clock but not motor delay variability. The findings implicate the basal ganglia and its thalamocortical connections in timing operations.

http://psycnet.apa.org/journals/neu/12/1/3.pdf

Temporal processing in the basal ganglia

Dysfunction of the basal ganglia and the brain nuclei interconnected with them leads to disturbances of movement and cognition, including disordered timing of movement and perceptual timing deficits. Patients with Parkinson's disease (PD) were studied in temporal reproduction tasks. We examined PD patients when brain dopamine (DA) transmission was impaired (OFF state) and when DA transmission was reestablished, at the time of maximal clinical benefit following administration of levodopa + apomorphine (ON state). Patients reproduced target times of 8 and 21 sec trained in blocked trials with the peak interval procedure, which were veridical in the ON state, comparable to normative performance by healthy young and aged controls (Experiment 1). In the OFF state, temporal reproduction was impaired in both accuracy and precision (variance). The 8-sec signal was reproduced as longer and the 21-sec signal was reproduced as shorter than they actually were (Experiment 1). This ''migration'' effect was dependent upon training of two different durations. When PD patients were trained on 21 sec only (Experiment 2), they showed a reproduction error in the long direction, opposite to the error produced under the dual training condition of Experiment 1. The results are discussed as a mutual attraction between temporal processing systems, in memory and clock stages, when dopaminergic regulation in the striatum is dysfunctional.

Coupled Temporal Memories in Parkinson's Disease: A Dopamine-Related Dysfunction

Parkinsonism reduces coordination of fingers, wrist, and arm in fine motor control

ADL 5 activities of daily living; ANOVA 5 analysis of variance; HM 5 Happiness Measure; MS 5 motor subscale; MT 5 music therapy; PD 5 Parkinson’s disease; PDQL 5 Parkinson’s Disease Quality of Life Questionnaire; PT 5 physical therapy; UPDRS 5 Unified Parkinson’s Disease Rating Scale.

Active music therapy in Parkinson's disease: an integrative method for motor and emotional rehabilitation.

A tapping test in which the tasks required a synchronous response to a periodic sound signal by the finger tapping was performed by 27 normal subjects and 146 patients with Parkinson's disease. Some patients could not maintain a synchronous response at a critical frequency of 2.5 or 5 Hz (taps per second) and showed a hastened tapping of 5 6 Hz, independent of the input signal frequencies, i.e., the 'hastening phenomenon.' The other patients and normal subjects could respond synchronously up to 5 7 Hz. Autocorrelational analysis of the sequential tapping intervals suggested that the synchronized response was performed by a feedback control with the input signal as target except at 2.5 and 5 Hz, whereas the hastened tapping of patients was a random process. The frequency-dependence of the error in the tapping was interpreted as representing an intrinsic oscillation in the central nervous system, which would be masked in normal subjects but released in patients with Parkinson's disease. Around 2.5 or 5 Hz the error or response becomes so large that some patients can no longer maintain the synchronized response and show a hastened tapping due to this intrinsic oscillation.

H Nagasaki

Papers

Disturbances of rhythm formation in patients with Parkinson's disease: part I. Characteristics of tapping response to the periodic signals.