F. Temporiti1,2, P. Adamo1, F. Natali1, E. Cavalli1, R. Gatti1,2
1Humanitas Clinical and Research Center - IRCCS, Milan, Italy, 2Humanitas University, Milan, Italy

Background: The discovery of the Mirror Neuron System has promoted the development of Action Observation Therapy (AOT) to improve motor and functional abilities in patients with Parkinson’s disease (PD). This innovative approach involves the observation of video-clips showing motor contents, which may vary across the studies influencing AOT efficacy. To date, no studies have systematically summarized the effects of AOT in patients with PD on motor and functional outcomes, underlining the characteristics of visual stimuli in relation to their efficacy.  

Purpose: The aim of this study was to describe the potential benefits of AOT in patients with PD and discuss the characteristics of visual stimuli in relation to their efficacy.

Methods: A systematic literature search was carried out using MEDLINE, PubMed, EMBASE, Scopus and PEDro databases, from inception until March 2020. Randomized controlled trials investigating the effects of AOT on motor and functional recovery in patients with PD were included. Two independent reviewers appraised the records for inclusion, assessed the methodological quality (PEDro scale) and extracted the following data: number and characteristics of participants, features and posology of the treatments, outcome measures at each follow-up and main results. Findings were aggregated into a quantitative synthesis (mean difference and 95% confidence interval) for each time-point.

Results: Seven studies (189 participants) with a mean PEDro score of 6.1 (range: 4-8) points were selected. AOT effects were found on walking ability (mean difference -2.2 seconds for 10-Meter Walking Test) and typical motor signs such as freezing of gait (mean difference from -1.6 to -5.8 for Freezing of Gait diary and from -5.7 to -6.3 for New Freezing of Gait Questionnaire) and bradykinesia (mean difference: -145 milliseconds for inter-tapping interval). Additional benefits on disability (mean difference: from -5.6 to -7.0 for Unified Parkinson’s Disease Rating Scale II and from -17.8 to 23.2 for Unified Parkinson’s Disease Rating Scale III) and quality of life (mean difference: from 28.1 to -31.1 for Parkinson’s Disease Questionnaire - 39 related to mobility and of -18.7 for Parkinson’s Disease Questionnaire - 39 related to bodily discomfort) were found when the intervention was associated with ecological auditory cues.   
Included studies adopted AOT stimuli with heterogeneous posology (from a single session to 8 weeks) and characteristics of motor contents might be responsible for different motor and functional recovery (person-related perspective, transitive or intransitive actions, healthy subjects or patients and association or not with imitation).

Conclusion(s): AOT leads to improvements in motor and functional performance in patients with PD, especially in terms of walking abilities and gait-related disorders. The characteristics of the training and the visual stimuli play a role in determining the AOT effects.

Implications: When implemented in clinical practice, AOT treatments should last at least 4 weeks and incorporate ecological auditory stimuli, if applicable. Imitation of observed actions is suggested and visual stimuli should facilitate patients’ empathy through person-related perspective (third person for locomotor tasks and first person for upper limb activities), transitive actions belonging to patients’ motor repertoire and similarity of actors with the clinical condition of observers.

Funding, acknowledgements: The authors did not receive any funding.

Keywords: Parkinson’s disease, Action Observation Therapy, Functional recovery

Topic: Neurology: Parkinson's disease

Did this work require ethics approval? No
Institution: Humanitas Clinical and Research Center - IRCCS
Committee: Internal Ethical Committee of the Humanitas Clinical and Research Center
Reason: The study is a systematic review of the literature.

All authors, affiliations and abstracts have been published as submitted.

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