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

Abstract

Freezing of gait (FoG) is a disabling symptom associated with 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's disease (PD) and FoG, using functional, and clinical scales. The experimental protocol was based on AO plus Sonification. 12 patients were treated with 8 motor gestures. They watched eight videos showing an actor performing the same eight 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 NFOG questionnaire, and the UPDRS (parts II and III). Importantly, all these improvements were consistently observed at the end, 1 month, and 3 months after treatment. No improvement effects were found in the group of patients treated with the standard protocol. These data suggest that a multisensory approach based on AO plus Sonification, with the two stimuli semantically related, could help PD patients with FoG to relearn gait movements, to reduce freezing episodes, and that these effects could be prolonged over time.

Keywords: Parkinson’s disease; Sonification; action observation; cueing; freezing of gait.

Figure 1

Flowchart showing the structure of the study, enrollment and evaluation procedure, and how the patients were divided into the groups, and phases.

Figure 2

Improvement (gain) of the two groups in the primary outcome measure [New Freezing of Gait Questionnaire (NFOGQ)], at the three evaluation times. Error bars are 1 SE.

Figure 3

Improvement (gain) of the two groups in five secondary outcome measures [Unified Parkinson’s Disease Rating Scale: parts II and III (UPDRS) and Parkinson’s disease questionnaire 39 (PDQ39): mobility, bodily discomfort, and the total score], at the three evaluation times. Error bars are 1 SE.

Figure 4

Average discrimination accuracy expressed in terms of sensitivity (d′) of the linear discriminant analysis (LDA) algorithm. (A) Results of testing between-groups’ discrimination. Dark gray bars represent LDA results from the New Freezing of Gait Questionnaire (NFOGQ) and UPDRS III scales. Light gray bars represent LDA results from the PDQ39 mobility and bodily discomfort scales. (B) Results of testing within-subject discrimination. Dark and light red bars represent LDA results from the NFOGQ and UPDRS III scales for the Action Observation plus Sonification experimental group. Dark and light blue bars represent LDA results from the PDQ39 mobility and bodily discomfort scales, for the Cue control group.