Investigating Therapies for Freezing of Gait

Investigating Therapies for Freezing of Gait Targeting the Cognitive, Limbic, and Sensorimotor Domains

Freezing of gait (FOG) is arguably one of the most debilitating motor symptoms experienced by individuals with Parkinson's disease (PD). FOG may be caused by an overload of cognitive, limbic, and sensorimotor system activity in the basal ganglia. Therefore, the purpose of this study is to evaluate cognitive, limbic, and sensorimotor therapies in individuals with FOG. Participants in this study will undergo all three types of treatments in a randomized counterbalanced order. Each treatment will occur in 1 hour sessions, twice weekly for a period of 4 weeks.

Freezing of gait (FOG) is arguably one of the most debilitating motor symptoms experienced by individuals with Parkinson's disease (PD), and negatively impacts quality of life (Walton et al., 2015). Furthermore, advanced FOG does not respond well to treatments commonly used in Parkinson's disease (Nutt et al., 2011), therefore warranting the use of adjunct treatment options. The development of potential treatment strategies for FOG should focus on the underlying mechanism. The cross-talk model of FOG proposes that FOG may be caused by an overload of cognitive, limbic, and sensorimotor system activity in the basal ganglia, resulting in a depletion of dopaminergic resources, leading to FOG (Lewis & Barker, 2009). Hence, based on the cross-talk model, treatments targeting the cognitive, sensorimotor and limbic systems independently may lead to a reduction in FOG episodes. Previous studies have demonstrated the efficacy of therapies targeting these domains in PD and healthy individuals, however, these have yet to be explored in FOG. Therefore, the purpose of this study is to evaluate cognitive, sensorimotor, and limbic therapies in individuals with FOG. This study will employ a within-subjects design, in which participants will undergo all three treatments in a randomized counterbalanced order. Sessions for each type of treatment will occur for 1 hour, twice weekly for a period of 4 weeks. Participants will also undergo pre- and post-test assessments prior to and following each 4-week treatment period. The cognitive training will utilize the "Smartbrain Pro" computer software, which has previously demonstrated efficacy in individuals with Parkinson's disease (Paris et al., 2011). The sensorimotor training group will participate in proprioceptive training of the upper and lower limbs. This training will entail a target matching task, in which participants will produce active and self-defined movements while blindfolded (i.e. without visual feedback). The limbic training group will undergo cognitive behavioural therapy (CBT) focusing solely on anxiety symptoms.

Participants will independently complete cognitive exercises on the "Smartbrain Pro" computer software. These exercises aim to train different aspects of executive function. The difficulty level of each exercise will increase relative to each participant's progress. Sessions will last for one hour, occurring twice weekly for a period of 4 weeks.

Participants will undergo one-on-one sessions of cognitive-behavioural therapy (CBT) working with a therapist to establish an individualized CBT plan which will focus on symptoms of anxiety. Participants will complete a total of eight one-hour sessions over 4 weeks.

Participants will complete one-on-one sessions a target matching proprioceptive training protocol using their upper and lower limbs. For the upper limb target-reaching task, participants will be seated in front of a surface marked with ten targets. They will first visualize a specified target, then blindfolded and asked to reach towards that target with the blindfold on. The blindfold will then be removed allowing participants to view their performance relative to the target. This task will be repeated for the remaining targets on both sides and for both upper and lower limbs. Participants will complete a total of eight one-hour sessions over 4 weeks.

Training the cognitive domain may be accomplished by training various cognitive and executive functions with guided practice focusing on specific skills (e.g. visuospatial processing, executive function, memory, language, and attention). Cognitive training has been demonstrated to be efficacious in several studies in individuals with PD. Given the potential cognitive contribution to FOG episodes, this type of therapy may alleviate FOG by potentially improving upon planning, set-shifting, and/or response inhibition.

CBT has been demonstrated to be effective in the remediation of anxiety in individuals with PD. This may be beneficial to individuals experiencing FOG, given the evidence that anxiety may provoke FOG. During periods of elevated anxiety (e.g. walking in a threatening environment), freezers will be able to more efficiently process this limbic load resulting in greater resources available for movement control.

Currently, studies investigating proprioceptive training as a treatment in PD are limited. However, this type of training has potential by improving proprioceptive processing. It would be expected that due to this training, when sensorimotor processing is challenged during locomotion (e.g. by removing visual feedback and preventing compensation of proprioception deficits), freezers would experience less decrements to gait due to an enhanced ability to process sensorimotor demands.

Participants will walk approximately 9.75 metres for 12 trials. Recording of kinematic data will be done with eight Optotrak® cameras (Northern Digital, NDI, Waterloo, Ontario). Spatiotemporal gait parameters will be analyzed from this assessment.

Participants will walk approximately 9.75 metres for 12 trials. Recording of kinematic data will be done with eight Optotrak® cameras (Northern Digital, NDI, Waterloo, Ontario). Spatiotemporal gait parameters will be analyzed from this assessment.

Participants will walk approximately 9.75 metres for 12 trials. Recording of kinematic data will be done with eight Optotrak® cameras (Northern Digital, NDI, Waterloo, Ontario). Spatiotemporal gait parameters will be analyzed from this assessment.

This will also be administered in a paper-based format. This test will assess visuospatial function and set-shifting ability.

This will also be administered in a paper-based format. This test will assess visuospatial function and set-shifting ability.

This will also be administered in a paper-based format. This test will assess visuospatial function and set-shifting ability.

The Parkinson Anxiety Scale (PAS), which is a self-report questionnaire used to assess anxiety levels, will be administered to participants. This tool has demonstrated good concurrent validity in individuals with PD against other existing anxiety scales (Leentjens et al., 2014).

The Parkinson Anxiety Scale (PAS), which is a self-report questionnaire used to assess anxiety levels, will be administered to participants. This tool has demonstrated good concurrent validity in individuals with PD against other existing anxiety scales (Leentjens et al., 2014).

The Parkinson Anxiety Scale (PAS), which is a self-report questionnaire used to assess anxiety levels, will be administered to participants. This tool has demonstrated good concurrent validity in individuals with PD against other existing anxiety scales (Leentjens et al., 2014).

Participants will be asked to complete the New Freezing of Gait Questionnaire (NFOGQ) questionnaire developed by Nieuwboer and colleagues (2009). This provides a self-reported measure of frequency and duration of FOG episodes. This tool has been validated and proven to be highly reliable in individuals with PD, as well as assessing treatment interventions for FOG.

Participants will be asked to complete the New Freezing of Gait Questionnaire (NFOGQ) questionnaire developed by Nieuwboer and colleagues (2009). This provides a self-reported measure of frequency and duration of FOG episodes. This tool has been validated and proven to be highly reliable in individuals with PD, as well as assessing treatment interventions for FOG.

Participants will be asked to complete the New Freezing of Gait Questionnaire (NFOGQ) questionnaire developed by Nieuwboer and colleagues (2009). This provides a self-reported measure of frequency and duration of FOG episodes. This tool has been validated and proven to be highly reliable in individuals with PD, as well as assessing treatment interventions for FOG.

Inclusion Criteria: Either gender Diagnosed with idiopathic PD by a Neurologist Self-reported FOG with the use of UPDRS-II (Question 14) Confirmation of present FOG by a movement disorder specialist Able to walk 10 meters, unassisted Able to understand English instructions Exclusion Criteria: A neurological disease other than PD Peripheral neuropathy Clinically diagnosed with dementia

Chow R, Tripp BP, Rzondzinski D, Almeida QJ. Investigating Therapies for Freezing of Gait Targeting the Cognitive, Limbic, and Sensorimotor Domains. Neurorehabil Neural Repair. 2021 Mar;35(3):290-299. doi: 10.1177/1545968321992331. Epub 2021 Feb 9.