Action Observation Plus Sonification. A Novel Therapeutic Protocol for Parkinson’s Patient with Freezing of Gait

Freezing of gait (FoG) is a disabling symptom associated to falls, with little or no responsiveness to pharmacological treatment. Current protocols used for rehabilitation are based on the use of external sensory cues. However, cued strategies might generate an important dependence on the environment. Teaching motor strategies without cues (i.e. action observation - AO - plus sonification) could represent an alternative/innovative approach to rehabilitation that matters most on appropriate allocation of attention and lightening cognitive load. We aimed to test the effects of a novel experimental protocol to treat patients with Parkinson disease (PD) and freezing of gait, using functional, and clinical scales. The experimental protocol was based on action observation plus sonification. 12 patients were treated with 8 motor gestures. They watched 8 videos showing an actor performing the same 8 gestures, and then tried to repeat each gesture. Each video was composed by images and sounds of the gestures. By means of the sonification technique, the sounds of gestures were obtained by transforming kinematic data (velocity) recorded during gesture execution, into pitch variations. The same 8 motor gestures were also used in a second group of 10 patients; which were treated with a standard protocol based on a common sensory stimulation method. All patients were tested with functional and clinical scales before, after, at 1 month, and 3 months after the treatment. Data showed that the experimental protocol have positive effects on functional and clinical tests. In comparison with the baseline evaluations, significant performance improvements were seen in the N-FOG questionnaire, and the UPDRS (part 3 and 2). Importantly, all these improvements were consistently observed at the end, 1 month, and 3 months after treatment. No improvements effects were found in the group of patients treated with the standard protocol. These data suggest that a multisensory approach based on action observation plus sonification, with the two stimuli semantically related, could help PD patients with FoG to re-learn gait movements, to reduce freezing episodes, and that these effects could be prolonged over time.