Exploring the Effects of Exercise on Memory and Cognition in Parkinson´s Disease

Heidelberg University60 enrolled

Overview

The study aims to assess the effects of cardiovascular (aerobic) training on memory formation and cognitive function in people with Parkinson's disease. Participants will be randomly allocated to one of two groups either performing cardiovascular training (experimental group) or stretching (control group) for twelve weeks, three times a week. The primary aim is to examine whether moderate-intense cardiovascular training (MICT) improves procedural memory formation (primary outcome) compared to stretching. Secondary outcomes include episodic memory formation, cognitive function, cardiorespiratory fitness, sleep quality, and brain-derived neurotrophic factor (BDNF) blood concentration levels.

Besides the disabling cardinal motor symptoms, non-motor symptoms are a common clinical feature of Parkinson's disease (PD). These non-motor symptoms include, amongst others, cognitive decline and memory deficits. A growing body of evidence suggests that cardiovascular training has the potential to induce functional and structural brain changes that can translate into improved cognitive function, including memory. While data is mainly derived from studying rodents and healthy populations, cardiovascular exercise might also counteract cognitive decline and memory deficits in people with Parkinson's disease (pwPD). Therefore, the primary aim of the study is to investigate the effects of a twelve-week cardiovascular training on memory formation in pwPD. In a randomized controlled trial, 60 persons with mild to moderate PD (i.e., Hoehn \& Yahr ≤3) will either perform moderate-intensity cardiovascular training (experimental group) or stretching (control group) for twelve weeks (three times per week, totaling 36 training sessions; duration per training session 30 to 55 min). Participants will perform a procedural memory task before and after the intervention to analyze the effects on non-declarative memory formation (primary outcome). In addition, secondary and exploratory analyses will include the assessment of episodic memory formation, cognitive function, cardiorespiratory fitness, sleep quality, and BDNF blood concentration levels. The findings of the present study contribute to the current discussion on the neuroplastic effects of cardiovascular training and may have important implications for neurorehabilitation in pwPD.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Interventions

cardiovascular trainingBEHAVIORAL

Cardiovascular training will be performed in supervised sessions and in small groups of 2-5 persons at the study site. The training is performed on a cycle ergometer at 60% of peak power output (Wmax) for 30 min (i.e., 5 min warm-up, 20 min at 60% Wmax, 5 min cool-down) three times a week for twelve weeks. The exercise program will be increased by 5 min (max. 55 min) and 5% of intensity (in Watt) every two weeks. If participants report a too low (i.e., Borg scale ≤ 11) or too high (i.e., Borg scale ≥ 16) subjective rate of perceived exertion (RPE; Borg scale 6-20) intensity will be increased or decreased until the target levels are met (i.e., Borg scale 12-15). During training, heart rate, intensity (in Watt) and RPE will be monitored. Participants missing training sessions will be offered an additional week to perform up to three training sessions.

stretchingBEHAVIORAL

The stretching training will be performed in supervised sessions and in small groups of 2-5 persons at the study site. Stretching training consists of lying, seated, and standing flexibility exercises (according to the recommendations of the American Parkinson´s Disease Foundation and the Parkinson Society Canada) for 30 min (i.e., 5 min warm-up, 20 min main part, 5 min cool-down) three times a week for twelve weeks. The exercise program will be increased by 5 min (i.e., adding additional repetitions and exercises; max. 55 min) every two weeks. Intensity of stretching exercises will be assessed by subjective rate of perceived muscle tension on a visual analog scale (VAS) from 0 to 10 and will be moderate defined as 5 to 7 on the VAS. During training VAS, heart rate, and RPE will be monitored. Participants missing training sessions will be offered an additional week to perform up to three training sessions.

Eligibility

Sex: ALLMin age: 50 YearsMax age: 80 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Diagnosed Parkinson's disease * Disease stage ≤3 on the Hoehn \& Yahr scale * Age ranging from 50 - 80 years * Naive to the memory tasks (primary outcomes) * Ability to stand and walk at least 10 meters independently Exclusion Criteria: * Atypical Parkinsonism * Significant level of cognitive impairment (i.e., Montreal Cognitive Assessment \<21) * Deep brain stimulation or brain pacemaker * Diagnosed psychiatric illness * Known clinically relevant neurological, internal or orthopedic conditions besides Parkinsonism that would interfere with the exercise paradigm * Exceeding the recommended level of cardiovascular exercise for older adults (i.e., cardiovascular exercise done ≥150 min per week of moderate-intensity or ≥75 min per week of vigorous-intensity)

Outcomes

Primary Outcomes

Non-declarative, procedural memory (motor sequence learning) global learning score - Visuomotor Serial Targeting Task (VSTT)

To evaluate non-declarative (procedural) memory formation, a Visuomotor Serial Targeting Task (VSTT) will be used, which is widely applied to study motor sequence learning. A global motor learning score (i.e., \[relative\] change from start of encoding to 24h recall test) will be calculated for explicit (i.e., correct anticipatory movements defined as movements with onset times lower than in random trials and directed to the correct target \[directional error at peak velocity \<22°\]) and implicit (i.e., spatial error to target defined as shortest distance of the movement end point from the center of the target) components of motor sequence learning and the change (delta) in the global motor learning scores from pre- to post-assessment will be analyzed. Hence, two outcome measures from the VSTT are considered to answer the primary research question: (i) change in explicit global motor learning score, and (ii) change in implicit global motor learning score from pre- to post-assessment.