We hear a lot about physiotherapists’ involvement with Parkinson’s disease. How many people have the disease?

Parkinson’s disease affects over 6 million people globally.

Because of the rapidly ageing population, the number of people affected by Parkinson’s disease is projected to double to over 12 million by 2040.

What are the clinical features of Parkinson’s disease?

The cardinal motor symptoms of Parkinson’s disease are bradykinesia, rigidity, tremor and postural instability.

These may give rise to a variety of secondary impairments, such as muscle weakness, altered gait, reduced aerobic capacity and falls.

These secondary impairments, along with the worsening of the motor symptoms as the disease progresses, may trigger a vicious cycle of further decline in physical activity level, activity and participation.

Apart from motor impairments, Parkinson’s disease is also characterised by non-motor symptoms, including fatigue, depression, anxiety, sleep disturbance, cognitive impairments, bladder or bowel dysfunction and behavioural issues.

With the enormous amount of evidence available, how did you tackle summarising it?

A thorough search of the literature was performed, but I mainly focused on summarising the evidence gathered from available systematic reviews and meta-analysis papers.

For certain physiotherapy interventions, an updated meta-analysis is warranted.

This was done by extracting the relevant studies from available systematic reviews and then adding data obtained from more recent trials.

In our meta-analytic approach, only those trials with a comparison group that allowed the delineation of the effects of the experimental intervention were included (ie, experimental intervention versus no intervention/sham intervention/attentional control, or experimental intervention and other intervention(s) versus the same other intervention(s) only).

Based on the information gathered, each intervention approach is classified into two categories (benefit from intervention versus uncertain effects) with an associated level of evidence (systematic review of multiple randomised controlled trials, multiple high-quality randomised controlled trials, a single high-quality randomised controlled trial or several low-quality randomised controlled trials).

With this rigorous approach, did many physiotherapy interventions prove to be beneficial?

Many physiotherapy interventions did prove to be beneficial.

In particular, a variety of exercise training methods confer benefits, including aerobic training, resistance training, treadmill training, dance exercise therapy, balance exercises, action observation training, robot-assisted gait training, cueing and movement strategy training, aquatic exercise, tai chi, dual-task training and exercise training using virtual reality in supervised and centre-based conditions.

Certain adjunct interventions, such as repetitive transcranial magnetic stimulation of the motor cortex, also have positive effects on motor function.

Telerehabilitation, which is of great relevance today, is also beneficial to people with Parkinson’s disease.

What about areas for future research?

The use of qi gong, yoga, Nordic walking, respiratory muscle training and transcranial direct current stimulation requires further research due to the limited evidence.

Delivery of physiotherapy service through telecommunication technologies should be further explored.

More efforts should be directed towards developing innovative telerehabilitation services for people with Parkinson’s disease delivered by physiotherapists and evaluating their efficacy and cost-effectiveness.

Future research is also warranted to identify the optimal exercise protocols for improving more complex walking tasks (eg, dual tasking) and freezing of gait.

More work is also needed to investigate the effects of different types of exercise training on non-motor outcomes in Parkinson’s disease.

>> Marco Pang is a professor in the Department of Rehabilitation Sciences and the director of the University Research Facility in Behavioral and Systems Neuroscience at the Hong Kong Polytechnic University. He is the editor-in-chief of the Hong Kong Physiotherapy Journal and the president of the Hong Kong Physiotherapy Association.