Exercise as it relates to Disease/Benefits of exercise on Parkinson disease

This article is in regards to the improvement of cognition and quality of life from exercise with populations that are effected by Parkinson's Disease (PD).

What is the Background for this research?
Parkinson's disease (PD) is typically defined as a disorder of movement, where sufficient levels of dopamine are not produced by the brain. Generally, this disease is onset between the ages of 50-65 with a prevalence of around 100-200 cases per 100,000 within the general population, accounting to an annual incidence of 20% per 100,000.

In 2012, diseases of the nervous system accounted for 6,884 deaths (4.7% of total registered deaths), with Parkinson's accumulating 20.2% (1391 deaths) of these incidences (0.9% of all registered deaths) and male deaths being higher than female (788 male, 604 female). Although PD has a major effect on the physical ability of a person, there are also psychological/psychosocial factors such as depression and cognitive impairment that play a role in the quality of life, though this factor is subjective and individualised. Subtle cognitive impairment is a characteristic of early PD while dementia and severe cognitive impairment regularly occur with a longer duration of PD.

Further research into this topic shows that regular exercise improves neurologically sound adults, not only physically but mentally. Regular exercise in the elderly with PD has been shown to provide benefits in trained groups versus the control groups of this study. With daily activities such as problem-solving, organisation and behavioural regulation, rely on efficient executive functioning (EF) to accomplish these tasks. With the given benefits of exercise on EF and the already harsh effects of Parkinson's on EF; there may be a key impact on the quality of life.

Where is the research from?
The research was conducted in Perth Western Australia at Edith Cowan University. With the participants for the study being recruited from the Parkinson's association of Western Australia (PWA). All participants were diagnosed with idiopathic PD after clinical evaluation with a neurologist and were under care by PD specialists throughout the duration of the study.

What Kind of Research was this?
The research design was based on a case-control study design, meaning that there were two populations - one group based as a control and one group with an intervention. The exercise intervention program was conducted at the vario health institute exercise clinic at Edith Cowan University, with all participants providing a written informed consent and the research project was approved by the ECU ethics committee and the PWA Research committee.

What did the research involve?
In this study both groups had PD and one was given a 12-week intervention period of an exercise intervention program (EIP) and the other group was delayed exercise (control group) based on a convenient sample method. The study used three different assessments of neuropsychological, Mood and disease-specific quality of life (QoL).

Neuropsychological
MMSE (Mini-Mental State Examination), WAIS (Weschler adult intelligence scale) Verbal IQ was estimated using Australian national adult reading test (AUSNART).

Mood
15 item geriatric depression scale (GDS)

Disease specific QoL
Parkinson's disease questionnaire (PDQ-39).

What were the Basic Results?
Both groups had been diagnosed with PD for a similar mean period (EIP 5.87±3.18; Control 5.46±3.63) with no significant difference between MMSE and WAIS verbal IQ results.

Mini-mental state examination (MMSE)
EIP 28.13 ± 1 .84; control 27.62 ± 1.32

WAIS verbal IQ
109.41 ± 7.69; control 111.39 ± 5.91

Neuropsychological
Exercise was not shown to have a negative impact on either measured outcome. Exercise showed likely benefit on improving verbal fluency and reducing spatial working memory (SWM) errors. Exercise was shown to have ‘possible benefit’ on category or semantic fluency for animals (CFA). Though no clinical benefits were shown for either group.

What conclusions can we take from this research?

 * Exercise was shown to provide a benefit for frontal lobe based executive functioning (spatial working memory and verbal fluency, both semantic and category).
 * Mood and disease QoL were not improved by exercises, 71% of the sample were within the normal range for depression (GDS 0–4); with higher scores (only 2) relating to lower QoL.
 * Population samples were selected from PD support groups (actively seeking support and disease management). Research involved a lot of commitment meaning that more motivated participants may have taken part.

Practical Advice
In further research, it would be advantageous to provide the studies with a variety of participants not only participants that are currently involved in a PD support group. This would allow for a wider comparison on more than one group (two from PD support group; two from no support group with PD) also selecting participants from a clinic setting rather than a support group. From an analysis of other papers, one of the important factors that influence QoL is MADRS score (Montgomery-Asberg depression rating scale). This scale is used for evaluation of depression using a 9-item scale. Another scale that can be used for depression is the Hamilton Depression rating scale (HAM-D). This scale allows for the best psychometric properties when an analysis of multiple depression scales are used

Further Reading/Information
For further information and readings click on the links below:
 * Original Article: https://onlinelibrary.wiley.com/doi/full/10.1111/j.1600-0404.2010.01338.x
 * Parkinsons Australia: http://www.parkinsons.org.au/aboutparkinsons
 * World Health Organisation, Neurological diseases: http://www.who.int/mental_health/neurology/neurodiso/en/
 * Mayo clinic, Parkinsons Disease: https://www.mayoclinic.org/diseases-conditions/parkinsons-disease/symptoms-causes/syc-20376055
 * National institute on aging, Parkinsons Disease: https://www.nia.nih.gov/health/parkinsons-disease