Volume 2012, Issue 1 854328
Review Article
Open Access

Exercise and Motor Training in People with Parkinson′s Disease: A Systematic Review of Participant Characteristics, Intervention Delivery, Retention Rates, Adherence, and Adverse Events in Clinical Trials

Natalie E. Allen

Corresponding Author

Natalie E. Allen

Clinical and Rehabilitation Research Group, Faculty of Health Sciences, The University of Sydney, P.O. Box 170, Lidcombe, Sydney, NSW 1825, Australia sydney.edu.au

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Catherine Sherrington

Catherine Sherrington

Musculoskeletal Division, The George Institute for Global Health, The University of Sydney, Sydney, NSW 2050, Australia sydney.edu.au

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Gayanthi D. Suriyarachchi

Gayanthi D. Suriyarachchi

Clinical and Rehabilitation Research Group, Faculty of Health Sciences, The University of Sydney, P.O. Box 170, Lidcombe, Sydney, NSW 1825, Australia sydney.edu.au

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Serene S. Paul

Serene S. Paul

Clinical and Rehabilitation Research Group, Faculty of Health Sciences, The University of Sydney, P.O. Box 170, Lidcombe, Sydney, NSW 1825, Australia sydney.edu.au

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Jooeun Song

Jooeun Song

Clinical and Rehabilitation Research Group, Faculty of Health Sciences, The University of Sydney, P.O. Box 170, Lidcombe, Sydney, NSW 1825, Australia sydney.edu.au

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Colleen G. Canning

Colleen G. Canning

Clinical and Rehabilitation Research Group, Faculty of Health Sciences, The University of Sydney, P.O. Box 170, Lidcombe, Sydney, NSW 1825, Australia sydney.edu.au

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First published: 16 November 2011
Citations: 34
Academic Editor: Gammon M. Earhart

Abstract

There is research evidence that exercise and motor training are beneficial for people with Parkinson′s disease (PD), and clinicians seek to implement optimal programs. This paper summarizes important factors about the nature and reporting of randomized controlled trials of exercise and/or motor training for people with PD which are likely to influence the translation of research into clinical practice. Searches identified 53 relevant trials with 90 interventions conducted for an average duration of 8.3 (SD 4.2) weeks. Most interventions were fully supervised (74%) and conducted at a facility (79%). Retention rates were high with 69% of interventions retaining ≥85% of their participants; however adherence was infrequently reported, and 72% of trials did not report adverse events. Overall, the labor-intensive nature of most interventions tested in these trials and the sparse reporting of adherence and adverse events are likely to pose difficulties for therapists attempting to balance benefits and costs when selecting protocols that translate to sustainable clinical practice for people with PD.

1. Introduction

In recent years there have been an increasing number of randomized controlled trials assessing the effects of exercise and/or motor training in people with Parkinson’s disease (PD). Overall, these trials support exercise and motor training as beneficial in improving walking, balance, muscle strength, and the performance of functional tasks in people with mild-to-moderate PD [111]. In order for findings from this research to be of general benefit to people with PD, therapists need to be able to translate the protocols used in the research into clinical practice [12].

Evidence-based practice aims to incorporate and apply high-quality clinical research findings in clinical policy and practice [13, 14]. However, this can be a challenging task as health practitioners may find it difficult to assess, interpret, and implement research evidence [13]. While evidence about beneficial outcomes is paramount in therapists’ decisions to implement a particular intervention, there are other factors that affect how the overall impact of the intervention is interpreted and its potential for widespread clinical application [1317]. For example, therapists need to consider how the characteristics of participants included in a trial may affect their decision regarding the applicability of the trial intervention with their patients [14]. It is likely that the way in which the intervention was applied in terms of its duration, level of supervision, delivery (i.e., individual versus group), and location (e.g., facilities and equipment required) will influence therapists’ decisions to implement that intervention. A research protocol that has been shown to be effective may not be implemented by therapists if they cannot provide adequate supervision over the required time frame or they do not have access to necessary facilities or equipment. Finally, information regarding retention, adherence, and adverse events is required so that therapists and patients can weigh up the effectiveness of the intervention against its acceptability and any risks associated with implementation [14].

Therefore, in order to examine the information available to guide the translation of research into clinical practice, we searched randomized controlled trials of exercise and/or motor training for people with PD to determine the
  • (1)

    disease severity and cognitive status of the included participants,

  • (2)

    duration, supervision, delivery, and location of the interventions,

  • (3)

    rates of retention, adherence, and adverse events.

2. Methods

2.1. Data Sources and Searches

Randomized controlled trials of exercise and/or motor training for people with PD were identified via database searches of MEDLINE, EMBASE, AMED, PsycINFO, the Cochrane Central Register of Controlled Trials, and CINAHL. The initial search was conducted in 2009, with a subsequent search conducted over 5 days from the 7th of April, 2011. The electronic search strategy used has been previously reported [2]. The Physiotherapy Evidence Database (PEDro; http://www.pedro.org.au/) was also searched, and the reference lists of previously published systematic reviews [4, 5, 8, 9, 1830] were checked for any trials not identified with the database search.

2.2. Study Selection

Trials included were published randomized (or quasi randomized, i.e., not truly random but intended to produce similar groups, such as allocation by odd and even birth dates [31]) controlled trials of people with PD where at least one of the interventions was an ongoing program of exercise and/or motor training. All forms of exercise (e.g., aerobic, strength, and treadmill walking) and motor training (e.g., cueing and movement strategy training) were included. Whole-body vibration was not considered to be exercise or motor training. Trials were excluded if the intervention was multidisciplinary or was primarily occupational therapy.

The eligibility of trials was determined in a two-stage process. Firstly, all trial titles and abstracts were screened independently by two investigators (N. E. Allen and G. D. Suriyarachchi). Trials were excluded if it was clear that they did not meet the inclusion criteria. Secondly, the full article was obtained for the remaining trials and each trial was assessed independently by at least two investigators (N. E. Allen, C. G. Canning or J. Song), using a standardized form containing the details of the inclusion criteria. Care was taken to identify trials that had been reported in more than one journal article. Where this occurred, the multiple articles were counted as one trial and all articles were used to collect data for that trial.

2.3. Data Extraction

A data collection form was developed, tested on five randomly selected trials and then modified accordingly. All investigators were involved in data extraction, and all data was double-checked by an investigator not involved in its initial extraction (N. E. Allen or J. Song). Discrepancies were resolved by discussion.

Information extracted from each trial included a description of participants (including cognitive status), details of the exercise and motor training program and how it was administered, as well as details regarding retention rates, adherence to the intervention, and monitoring and reporting of adverse events. Retention was defined as the number of participants who completed the trial (i.e., undertook the first or only post-intervention assessment excluding further follow-up assessments) expressed as a percentage of the number of participants who began the trial. Adherence was defined as the number of intervention sessions attended by participants expressed as a percentage of the number of intervention sessions prescribed [15].

3. Results

Searching identified 3,539 records, of which 53 trials involving 1,940 participants were found to be eligible for inclusion in the paper (Figure 1) [32]. There were no disagreements between reviewers regarding the inclusion of any articles. The characteristics of the included trials [1, 3, 6, 7, 10, 11, 3385] are summarised in Table 1.

Table 1. Characteristics of the 53 included trials.
First author, year and intervention type Initial group sizes Disease severity Location and delivery of experimental intervention Duration of intervention (weeks) Hours of intervention (approx) Supervision (%) Retention (%) Any dropouts related to intervention? Adherence (%) Adverse events occurred
Allen 2010, Mild to Facility, group
exercise OR 24 moderate + home individual 26 65 10% 87.5% Y 70% N
control 24 100%
  
Ashburn 2007, Moderate Home,
exercise and 70 individual 6 33 18% 96% Y U (99% of Supervised exercise) N
strategy OR
control 72    92%
  
  • Bergen 2002,
  • aerobic
  • exercise OR
Mild Facility, NA NR NRM
4 delivery 16 32 100% 100%
unclear
control 4 100%
  
Blackinton 2002, U Mild to Facility, U NR NRM
exercise OR 15 moderate group + home 6 15 66% 53% Y
control total individual total
  
Bloomer 2008, Mild Facility,
resistance 8 delivery 8 8 100% 75% N U N
training OR unclear
control 8 88%
  
Braun 2011, Mild to Facility, U NRM
physiotherapy moderately individual or 6 + home
+ mental 25 severe group + home, 6 mental U (100%) 88% Y (87%)†‡
practice OR individual practice
physiotherapy + relaxation 22 6 6 + home relaxation U (100%) 82% (88%)†‡
  
Bridgewater Mild to Facility, group NA NRM
1996 (also as [38]), moderate
aerobic and 13 12 16 to 22 100% 100% 95%
  • trunk muscle
  • training OR
education 13 12 4 100% U
  
Burini 2006*, Mild to Facility, group NRM
aerobic 13 moderate 7 17 100% 85% Y 87%
exercise OR
Qigong 13 7 17 100% 85% Y 88%
  
Caglar 2005, Mild to Facility, group NA NRM
exercise OR 15 moderate + home, 9 63 4% 100% 100%
control 15 individual
  
Cakit 2007, Mild to Facility, NR Partial—
treadmill 27 moderate delivery 8 8 100% 78% U 2 minor
walking OR unclear cardiac
control 27 37%
  
Comella U Mild to Facility, U NRM
1994*, 18 moderate delivery 89% total
physiotherapy total unclear 4 12 100% U U
OR
control
  
de Bruin 2010, Mild to Home,
walk with 16 moderate individual 13 19.5 0% 69% Y 100% Y—1
music OR thigh
control 17 65% cramping
  • 1
  • tiredness
  
Dereli 2010, Mild to NRM
supervised 16 moderate Facility, 10 22.5 100% 94% Y 100%
  • exercise OR
  • home exercise
individual;
16 home, individual 10 22.5 4% 94% NR
  
Dias 2005, Mild to Facility, NA NRM
physiotherapy 8 moderate delivery 4 to 10 20 100% 100% 100%
+ cues OR unclear
physiotherapy 8 4 to 10 20 100% 100% 100%
  
Ebersbach 2010, Mild to moderate NR NRM
LSVT BIG 20 Facility, individual; 4 16 + home X U (100%) 100% NA
OR Nordic walking 20 facility, group; 8 16 + home  X U (100%) 95% U
OR home exercise 20 home, individual 4 U U 95% N
+ all did home, individual
  
Ellis 2005* Mild to Facility, group NRM
(also as [44]), moderate
physiotherapy 35 6 18 100% 91% N 93%
OR
control 33 94% N
  
Fisher 2008, Mild Facility, NA NR N
treadmill 10 delivery 8 18 100% 100%
walking OR unclear
physiotherapy 10 8 18 100% 100%
OR
control 10 100%
  
Frazzitta 2009, Moderate Facility, NA NR NRM
Treadmill 20 individual 4 9.5 100% 100%
walking with
cues OR
physiotherapy 20 4 9.5 100% 100%
with cues
  
Guo 2009, Mild to Facility, group NR NR NRM
physiotherapy 23 moderate education and individual 8 12 of therapy 100% 91%
and education therapy
OR
control 21 90%
  
Hackney 2007, Mild to Facility, NA NRM
Tango OR 9 Moderate group 13 20 100% 100% 100%
exercise 10 13 20 100% 100% 100%
  
Hackney 2008 Mild to Facility, NRM
(also as [54]), moderate group implied
Tai Chi OR 17 10 to 13 20 100% 76% Y 100%
control 16 81%
  
Hackney 2009 Mild to Facility, Partial—
(also as [54]), moderate group 1 knee
Waltz/foxtrot 19 10 to 13 20 100% 89% Y 100% pain
OR
tango OR 19 10 to13 20 100% 74% Y 100%
control 20 85%
  
Hackney 2010, Mild to Facility, group NRM
partnered 19 moderate 10 20 100% 79% Y 100%
tango OR
nonpartnered 20 10 20 100% 80% Y 100%
tango
  
Hass 2007, Mild to Facility, NA NR Y—1
resistance 10 moderate delivery 12 12 100% 100% muscle
training + unclear soreness
supplement and 1
OR Shoulder
resistance 10 12 12 100% 100% pain
training +
placebo
  
Hirsch 2003, Mild to Facility,
balance and 9 moderate delivery 10 22.5 100% 67% Y 89% Y—1
resistance unclear inguinal
training OR hernia
balance 9 10 15 100% 100% 92%
training
  
Keus 2007, Mild to Facility, NA
physiotherapy 14 moderately individual 10 11 to 15 100% 100% 63% N
OR control 13 severe 92%
  
Kurtais 2008, Mild to Facility, NR NRM
treadmill 13  moderate delivery 6 12 + U (100%) 92% Y
walking OR unclear + home X
home,
control 14 individual 86%
  
Lehman 2005a, Mild Facility implied, NA NR NRM
walk with 5 delivery unclear 2 5 100% 100%
  • verbal cues
  • OR control
6 100%
  
Mak 2008, Mild to Facility NR NRM
cued sit to 21 moderate Implied, 4 4 100% 90% U
stand OR delivery
OR exercise 21 unclear 4 6 100% 90% U
control 18 78%
  
Marchese U Mild to Facility, U NR NR NRM
2000, 20 moderate individual +
physiotherapy total home, 6 18 + U (100%)‡
OR individual home X
physiotherapy 6 18 + U (100%)‡
with cues home X
  
Miyai 2000*, Mild to Facility, NA NR NRM
treadmill 5 moderate individual 4 6 100% 100%
walking OR
physiotherapy 5 4 6 100% 100%
  
Miyai 2002, Mild to Facility, NR NRM
treadmill 12 moderate individual 4 6 100% 92% N
walking OR
physiotherapy 12 4 6 100% 75% N
  
Morris 2009, Mild to Facility, NA NRM
movement 14 moderate individual 2 Up to 12 100% 100% 88% of
strategies OR maximum
sessions
exercises 14 2 Up to 12 100% 100% 81% of
maximum
sessions
  
Müller 1997, Mild to Location and NR NR NRM
behavioural 15 moderate delivery 10 30 100% U
therapy OR unclear
nonspecific 14 10 30 100% U
exercises and information
  
  • Nieuwboer 2007*
  • (also as [61, 73]),
Mild to moderate
  • Home,
  • individual
  • Partial—
  • no falls
  • wearing
  • activity
  • monitor
cueing 76 3 4.5 100% 99% N 100%
training OR
control 77 100%
  
Pacchetti Mild to Facility, group U NR NR NRM
2000, moderate
physiotherapy 16 13 19.5 100%
OR
music therapy 16 13 26 100%
  
Palmer 1986, Mild to Facility, group NA NR NRM
exercise OR 7 moderately 12 36 100% 100%
seated karate 7 severe 12 36 100% 100%
  
Pelosin 2010, Mild to Facility, NA NR NRM
physiotherapy 9 moderate delivery 4 12 100% 100%
with FOG unclear
strategies OR
physiotherapy 9 4 12 100% 100%
  
Protas 2005, Mild to Facility, NA NRM
treadmill 9 moderate individual 8 24 100% 100% 100%
walking
and step
training OR
control 9 100%
  
Qutubuddin Mild to Facility, NRM
2007, moderate delivery
computerized 12 unclear + 8 18 20% 75% U U
dynamic home,
posturography individual
OR
physiotherapy 10 8 18 20% 60% U U
  
Ridgel 2009, Mild to Facility, NA NR NRM
forced cycling 5 moderate delivery 8 24 100% 100%
OR unclear
self-paced 5 8 24 100% 100%
cycling
  
Sage 2009, Mild to Facility, NRM
aerobic 17 moderate group 10 to 12 18 100% 76% Y 86.8%
exercise OR
SAFEx OR 21 10 to 12 20 to 34 100% 86% Y 92.9%
control 15 100%
  
Sage 2010, Mild to Facility, NA NRM
SAFEx OR 15 moderate group 12 36 100% 100% 100%
non-SAFEx 14 12 36 100% 100% 100%
  
Schenkman Mild to Location
1998, moderate unclear,
exercise OR 27 individual 10 to 13 22.5 to 30 100% 85% U 100%† N
control 24 96%
  
Schmitz- Mild to Facility group NR NRM
Hübsch 2006, moderately + home
Qigong OR 32 severe individual 24 16 + home X 66% 91% Y
control 24 87.5%
  
Smania 2010, Moderate Facility, NR NRM
balance 33 to individual 7 17.5 100% 85% Y
training OR moderately
general 31 severe 7 17.5 100% 87% Y
exercises
  
Stallibrass Mild to Facility, NRM
2002, moderate individual
Alexander 32 12 16 100% 91% Y 99%
technique
OR
massage OR 31 12 16 93% 97%
control 30 100%
  
Tamir 2007, Mild to Facility, NR Partial—
exercise + imagery 12 moderate delivery 12 24 + U (100%) 92% U 2 cardiac
OR unclear + home X problems
exercise 11 home, individual 12 24 + home X U (100%) 91% U
  
Thaut 1996, Mild to Home, NA
walk with 15 moderate individual 3 10.5 14% 100% 100% Y—1 fall
auditory cues
OR
walk without 11 3 10.5 14% 100% 100%
cues OR
control 11 100%
  
Toole 2000, Mild to Facility, NR NRM
exercise OR 6 moderately delivery 10 30 100% 67% N
control 5 severe unclear 60%
  
Toole 2005, U Mild to Facility, NR NR 99% NRM
treadmill 23 moderately delivery 6 6 100% overall
walking with total severe unclear
body weight
support OR
treadmill 6 6 100%
walking with
weights OR
treadmill 6 6 100%
walking
  
Yang 2010, Mild to Facility,
downhill 16 moderate delivery 4 6 100% 94% Y 100% N
treadmill unclear
walking OR
conventional 17 4 6 100% 88% Y 100% N
therapy
  
Yousefi 2009, Mild to Facility, NA NR NRM
exercise OR 12 moderate group 10 40 100% 100%
education 12 10 40 100%
  • Supervision: the number of intervention sessions supervised expressed as a percentage of the number of sessions prescribed; retention: the number of participants who completed the trial (i.e., undertook a post-intervention assessment but excluding follow-up) expressed as a percentage of the number of participants who began the trial; adherence: the number of intervention sessions participants attended expressed as a percentage of the number of intervention sessions prescribed; Y: yes; N: no; NA: not applicable; U: unclear—insufficient information to categorize; NR: not reported; NRM: not reported to be monitored; X: exercise; FOG: freezing of gait; SAFEx: sensory attention focused exercise; *cross-over trial;data only for participants who completed the trial;data only for the facility component of the intervention;apart 2 of trial only.
Details are in the caption following the image
PRISMA flow diagram [32] showing flow of information through the review.

3.1. Participant Characteristics

Forty (75%) of the reviewed trials included participants with mild-to-moderate PD (i.e., equivalent to Hoehn and Yahr stage I to III [86]). Seven trials (13%) included participants with mild-to-moderately severe PD (i.e., Hoehn and Yahr stage I to IV), while four trials (8%) included only participants with mild PD and two trials (4%) included only participants with moderate PD (Table 1). Most trials stipulated the cognitive status of included participants. Twenty-nine trials (55%) used the Mini-Mental State Examination [87] to screen potential participants’ cognitive abilities, with the minimum score for inclusion varying between 20 and 28 out of the maximum of 30 [1, 3, 6, 7, 10, 11, 34, 36, 39, 4143, 45, 4750, 56, 58, 60, 6365, 69, 71, 7678, 80, 85]. One trial (2%) [70] specified that participants required at least moderate scores on the Neurobehavioural Cognitive Status Examination [88]. Thirteen trials (25%) made a statement to the effect that included participants had no dementia and/or reasonable cognition [35, 46, 51, 52, 57, 59, 62, 66, 67, 79, 81, 83, 84]. Ten trials (19%) did not give a clear indication of the participants’ cognitive abilities [33, 37, 40, 53, 55, 68, 72, 74, 75, 82].

3.2. Exercise and/or Motor Training Program Characteristics

In the 53 trials, there were 90 intervention groups that involved exercise and/or motor training (including two intervention groups for the cross-over trials where one intervention was a control [11, 42, 47]) (Table 1). Average intervention duration was 8.3 weeks (SD = 4.2,   range = 2 to 26 weeks), with 37 trials (70%) conducting an intervention of 10 weeks or less. The total number of hours of intervention was not clearly reported in all studies (see Table 1); however, from the available data, an average of approximately 20 hours (SD approximately 11, range = 4 to 65 hours) appears broadly representative of the included trials. Sixty-seven of the 90 intervention groups (74%) involved full supervision of exercise and/or motor training. Participants in 18 (27%) of the fully supervised intervention groups received one-on-one supervision and 20 (30%) received supervision in small groups but the intervention delivery (one-on-one or small group supervision) was unclear in the remaining 29 (43%) intervention groups. Participants in most intervention groups (71; 79%) were required to attend a facility for all or the majority of the intervention sessions.

3.3. Retention, Adherence, and Adverse Events

Retention was generally well reported and was high, with 62 (69%) of the 90 intervention groups retaining at least 85% of participants (Table 1). Seventeen (32%) of the 53 included trials reported that at least one participant dropped out for a reason related to the intervention (Table 2). Difficulties with transport and disinterest/poor adherence were the most common intervention-related reasons for dropouts.

Table 2. Dropout reasons when related to the intervention.
First author and year Dropout reason Number of participants
Allen 2010 Did not want to do the intervention 1
Ashburn 2007 Falls (but not during intervention) 1
Blackinton 2002 Safety concerns 1
Braun 2011 Imagery too confronting 1
Burini 2006 Poor adherence to exercise; 2
back pain 1
de Bruin 2010 No access to necessary equipment 1
Dereli 2010 Did not want to do the intervention 1
Hackney 2008 (also as [54]) Exercise not intense enough; 1
transport problems 2
Hackney 2009 (also as [54]) Knee pain; 1
transport problems 2
Hackney 2010 Travel distance; 2
classes too fatiguing; 1
lack of interest 1
Hirsch 2003 Inguinal hernia 1
Kurtais 2008 Poor adherence to exercise 1
Sage 2009 Time commitment 4
Schmitz-Hubsch 2006 Uncomfortable in the group; 1
uncomfortable with Qigong 1
Smania 2010 Uncooperative 4
Stallibrass 2002 Could not travel 1
Yang 2010 Low motivation; 1
transport problems 1

Overall, adherence and adverse events were infrequently reported in the included trials (Table 1). Adherence was reported in some form in 26 (49%) of the included trials. However, 11 (42%) of these trials only reported adherence for those participants who completed the intervention. Most trials (38; 72%) did not report monitoring for adverse events. Across the remaining 15 trials, 11 adverse events occurred (Table 1). Four participants from two separate trials [41, 80] experienced cardiac problems. Two of these participants, one from each group in a trial comparing physical therapy with and without mental practice [80], withdrew from the study. The two participants from the other trial [41] were able to continue safely with treadmill training. Other adverse events reported included a fall [81] and muscle cramps and tiredness [43] in trials involving cued overground walking, knee pain during a dancing program [52], muscle soreness and shoulder pain [56] following resistance training, and a hernia [57] subsequent to muscle strength assessment.

4. Discussion

A substantial number of randomized controlled trials of exercise and/or motor training for people with PD have been published. However, the nature and reporting of these trials are likely to provide challenges for therapists aiming to implement the interventions into clinical practice [17]. Most trials involved only cognitively intact participants with mild-to-moderate PD. Trials tended to be of short duration, highly supervised, and conducted at a facility. Furthermore, the reports for many trials were lacking important details, with adherence and adverse events particularly being inadequately reported.

On the whole, trials included in this paper included only participants with mild-to-moderate PD who were without significant cognitive impairment. Including only these types of participants not only makes it easier to conduct trials of exercise and motor training interventions but also aids interpretation of the results. However, cognitive impairment is now recognised as a common problem in PD, with over 80% of people with PD ultimately developing dementia [89]. Further work is needed to determine the effectiveness of exercise and motor training in people with more severe cognitive impairment and/or more advanced disease.

Most of the reviewed trials were of short duration, highly supervised, and facility based (Table 1). Interventions lasted an average of around two months. Seventy-four percent of the intervention groups were fully supervised, with no reported expectation for participants to undertake unsupervised exercise. Furthermore, 79% of intervention groups were mainly conducted at a facility such as a hospital or university. Such brief, highly supervised interventions conducted in controlled environments are likely to improve the adherence of participants to exercise and motor training programs and to ensure that interventions are being performed optimally. In this regard, these trials are useful and important for determining the short-term efficacy of an intervention. However, given that PD is a long-term, neurodegenerative condition, the capacity of therapists and patients to sustain the intervention over the long term needs to be considered. Furthermore, such brief and highly supervised interventions are costly and less likely to give information about the effectiveness of the intervention when implemented into usual practice [13, 17]. For example, the requirement for participants to travel to a facility was a common reason for withdrawal from the included trials (Table 2). Moreover, the neurodegenerative nature of PD and the limited resources available to healthcare systems mean that such labor-intensive programs are unlikely to be sustained or afforded by most health-care providers. Additionally, as PD is a progressive disease it is important that people with PD are empowered to self-manage their disease to some extent [90, 91]. To this end, trials of more pragmatic and sustainable exercise and motor training interventions, with the potential for direct translation into clinical practice and including cost-effectiveness analysis, are needed.

The likely adherence to an exercise and motor training program is an important factor to consider when prescribing such a program for an individual with PD. Adherence to the intervention was reported in less than half of the included trials, and some reports of adherence are artificially elevated by including only those participants who completed the trial (Table 1). Some trials were able to effectively maximise adherence by providing a flexible timeframe for participants to complete the intervention [46, 51, 52, 74, 76] and so allow participants more options in fitting their exercise and/or motor training program around their daily lives. This pragmatic approach is likely to more closely reflect therapy attendance patterns and is therefore likely to be helpful for therapists considering translating the research into their clinical practice.

Given the importance of adherence to exercise and motor training programs, strategies to promote adherence in people with PD need to be considered. Providing a high level of supervision seems likely to promote adherence in the short term, as it may enhance participants’ commitment to the program. However, a Cochrane review comparing home and centre-based exercise programs for older adults found that, in the long term, participants were more likely to adhere to home-based programs [92]. Furthermore, the reviewers noted a trend toward more sustained improvements in the home-based than in the centre-based programs and suggested that this was attributable to the higher adherence in home-based programs. In the present paper, three of the included trials report high levels of adherence with minimally supervised home-based programs [40, 43, 81]. Common to all three of these trials was a requirement for participants to keep a daily record of what exercise/motor training they had performed. It seems likely that this simple strategy assisted in promoting adherence in these trials. Other strategies with the potential to improve adherence in sustainable, minimally supervised trials, such as participant involvement in goal setting [93, 94], flexibility to allow programs to be modified for individuals [1, 91, 93, 94], and intermittent followup [91, 94], warrant exploration.

The issue of adverse events was inadequately addressed in the trials included in this paper, with only 15 trials reporting monitoring for adverse events. In these 15 trials, 11 adverse events were reported, most of which were minor in nature (Table 1). However, when discussing and planning exercise and motor training options with people with PD, therapists need to be informed not only about the effectiveness of a given intervention but also about the nature and likelihood of any potential adverse events [95]. Similarly poor reporting of adverse events was found in a recent Cochrane review of progressive resistance training for older adults [95]. Notably, the Cochrane review found that adverse events were more likely to be detected in trials that used a clear definition of adverse events than in trials which did not use a definition. In the same way, the use of a definition for adverse events is likely to improve the assessment and reporting of adverse events in trials of exercise and motor training for people with PD.

This paper has examined several factors in the nature and reporting of trials of exercise and/or motor training which are likely to influence the way research is applied by therapists in clinical practice. However, this paper did not address whether or not trial protocols were reported in sufficient detail to allow therapists to emulate the research intervention in the clinic. This detailed reporting of trial interventions is critical in enabling research to be clinically applied [96]. The ability of many journals to provide online material which supplements the published article will aid the provision of such details despite the necessary word count limitations placed on authors.

5. Conclusions

Clinicians seeking to use research to inform their clinical practice rely heavily on the design and reporting of randomized controlled trials to reach their decisions. However, the nature and reporting of trials of exercise and/or motor training for people with PD are likely to provide challenges for therapists aiming to implement the interventions into clinical practice. The short duration, highly supervised and facility-based nature of many of the interventions, coupled with the tendency to include only cognitively-intact participants with mild-to-moderate disease, mean that findings may not generalise when therapists set out to apply them in the long-term management of people with PD. Infrequent reporting of adherence and adverse events compounds this problem and makes cost-benefit balancing more difficult. It is recommended that these issues be taken into account in the design and reporting of future trials.

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