Investigating Therapies for Freezing of Gait

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.