April 2018 – Joshua Kearney

Beck, Intzandt & Almeida (2018)

Gait, or walking, is a well-learned series of movements, achieved with little attention (so mostly subconscious), and facilitated by the basal ganglia. In particular, the dorsal striatum is implicated in the process, with loops to and from the sensorimotor cortex. The dorsal striatum is also the initial area of degeneration in Parkinson’s Disease, and so it makes sense that people with PD shift to a more conscious control of walking.

However, controlling gait more consciously increases the demand on attentional resources. As a result, when walking while completing a secondary task, people with PD display worsened gait – increased step time, percentage of time spent in double support, step-to-step variability, and decreased step length.

Cues can influence how movements are controlled. External cues, those that direct attention externally to the effect of an action on the environment, utilise automatic process, and sensorimotor cortical areas. Conversely, internal cues direct attention to one’s own limb movement, relying on conscious processes that linked to the frontal cortex. Continue reading “External exercise cues and dual task ability during gait in people with PD”

A particular type of exercise therapy has been developed at the Movement Disorders Research and Rehabilitation Centre (MDRC) in Waterloo, Canada, which has been found to improve symptom severity in people with Parkinson’s Disease. The programme encourages greater utilisation of proprioceptive information by reducing the reliance on vision and drawing greater attention to body awareness, and was thus termed sensory attention focused exercise, or PD SAFEx for short. Despite the success of PD SAFEx, it hadn’t been determined if the exercise programme positively impacted balance in participants.

And this is where the Lefaivre and Almeida’s 2015 study comes in. They also attempted to provide support for the theory that PD SAFEx worked by stimulating depleted populations of dopaminergic neurons in the basal ganglia Â to cause an adaptation, as opposed to bypassing the dysfunctional basal ganglia with a cortical pathway. This is important as the former process is more likely to give rise to better long term improvement in motor symptoms, as Sage and Almeida (2010) found only the PD SAFEx group (vs the non-SAFE group) maintained symptom alleviation following a six week washout period.

Continue reading “Lefaivre and Almeida (2015): Sensory integration exercise and balance control”