Canning 2008.

Methods	Parallel group design. Randomised using opaque envelopes pre‐prepared by an investigator and randomly allocated by staff member not involved in the trial. Data analysed on an intention‐to‐treat basis.. Treated at home 4 times a week for 6 weeks, for a total of 12 to 16 hours. Assessed at baseline, 6 and 12 weeks. Assessors were blinded.
Participants	10 participants in the treadmill group and 10 participants in the control group. Dropouts 2 (treadmill), 1 (control). Participants' mean age 60.7 years (treadmill), 62.9 years (control); male/female 5/5 (treadmill), 6/4 (control); Hoehn and Yahr stage not stated; duration of PD 6.1 years (treadmill), 5.2 years (control). Inclusion criteria: clinical diagnosis of idiopathic Parkinson's disease, aged 30 to 80 years, able to walk unaided but with subjective disturbance of gait and/or a Unified Parkinson's Disease Rating Scale (UPDRS) gait sub score of 1 or 2, sedentary, defined as performing less than 2 hours/week of leisure‐time physical activity over the prior 3 months, have adapted to current anti‐Parkinsonian medication for at least 2 weeks, is cognitively intact, has no freezing 'on' medication, Hoehn and Yahr stage 1 or 2. Exclusion criteria: motor fluctuations or dyskinesias that are disabling, requiring the use of a walking aid; more than one fall in the past 12 months, Mini‐Mental State Examination score < 24, exhibit other neurological or musculoskeletal conditions affecting walking, chest pain at rest or during exercise in the past 3 months, or heart attack, angioplasty, or heart surgery in the last 6 months.
Interventions	Treadmill: 30‐ to 40‐minutes sessions included 5‐minute warm up and cool down, sit‐to‐stand exercise and stretch exercises followed by treadmill walking. The intensity of training progressed over 6 weeks. Cognitive and manual tasks introduced during walking from week 4. Verbal and visual cues also provided for encouragement. 7 sessions were supervised in the home by a physiotherapist. Other sessions were completed independently. Control: advised to maintain current activity levels. 17 participants taking LD ranging from 100 to 1200 mg. 10 were also being treated with DA and 2 were also taking COMTI. Three (2 control and 1 experimental) were taking no PD medication.
Outcomes	6‐Minute walk test. UPDRS － motor examination. PDQ‐39. Walking automaticity, speed of walking 10 m while performing a concurrent (cognitive or cognitive + physical) task, as expressed as a percentage of the walking speed of walking 10 m without performing the concurrent task. Walking consistency determined as the coefficient of variation for stride time and stride length recorded during the 6‐minute walk test. 7‐pt Likert scale to assess fatigue. Examinations took place during 'on' periods.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Eligibility Criteria	Low risk
Randomisation Method	High risk	Randomised using opaque envelopes pre‐prepared by an investigator.
Concealment of Allocation	High risk	Randomly allocated by staff member not involved in the trial.
Similarity at Baseline	Low risk
Withdrawals Described	Low risk	10% dropout/withdrawal rate at 6 weeks (primary endpoint). Increases to 15% dropout/withdrawal rate by 12 weeks.
Intention To Treat Analysis	Low risk	Data analysed on an intention‐to‐treat basis.
Cointerventions Constant	Unclear risk	Not stated whether any changes to medications occurred during trial period.
Blinded Assessors	Low risk	Assessors were blinded to group allocation.