Pilot Study to Determine if Working Memory Training Aids Cognitive Functioning in Patients With Parkinson's Disease (PDWM)

• Baseline Working memory function [ Time Frame: baseline ] [ Designated as safety issue: No ]

  Working memory will be measured using the operation span task, the symmetry span task and the Sternberg memory scanning tasks.

  Operation span - This is a dual-task in which participants complete mathematical reasoning (e.g. solving a mathematical equation) while using short-term verbal memory to remember words.

  Symmetry span: This is a dual task in which participants discriminate about the symmetry of visual stimuli while using short-term spatial memory to remember the locations of stimuli.

  Sternberg memory scanning task - number memory test

• Change in working memory function between baseline and 5 weeks post training onset [ Time Frame: 5 weeks post training onset ] [ Designated as safety issue: No ]
• Change in working memory function between baseline and 10 weeks post training onset [ Time Frame: 10 weeks post training onset ] [ Designated as safety issue: No ]
• Change in working memory function between baseline and 22 weeks post training onset [ Time Frame: 22 weeks post training onset ] [ Designated as safety issue: No ]

• Baseline fluid intelligence [ Time Frame: Baseline ] [ Designated as safety issue: No ]
  Fluid intelligence will be measured using Cattell's Culture Fair Intelligence Test, a measure of analogical reasoning, and Raven's Progressive Matrices, a measure of spatial reasoning.
• change in fluid intelligence between baseline and 5 weeks post training onset [ Time Frame: 5 weeks post training onset ] [ Designated as safety issue: No ]
• Change in fluid intelligence between baseline and 10 weeks post training onset [ Time Frame: 10 weeks post training onset ] [ Designated as safety issue: No ]
• Change in fluid intelligence between baseline and 22 weeks post training onset [ Time Frame: 22 weeks post training onset ] [ Designated as safety issue: No ]
• Baseline Executive functioning [ Time Frame: Baseline ] [ Designated as safety issue: No ]
  Executive functioning will be measured using the Dysexecutive Questionnaire. It is a self-report and other-report of everyday behaviours reflecting executive function.
• Change in executive functioning between baseline and 5 weeks post training onset [ Time Frame: 5 weeks post training onset ] [ Designated as safety issue: No ]
• Change in executive functioning between baseline and 10 weeks post training onset [ Time Frame: 10 weeks post training onset ] [ Designated as safety issue: No ]
• Change in executive function between baseline and 22 weeks post training onset [ Time Frame: 22 weeks post training onset ] [ Designated as safety issue: No ]

This project will investigate the feasibility and preliminary effectiveness of an intensive and focused working memory training program for patients in the early stages of PD receiving dopaminergic therapy. The investigators hypothesize that working memory training will be an effective method of improving working memory and related cognitive and behavioural functions in PD patients.

Parkinson's disease (PD) is not an exclusively motor disease; more than half of individuals with PD experience cognitive impairment even in the early stages of the disease and many develop dementia as the disease progresses. As a result, attention, memory, planning and organizational skills can be affected, interfering with everyday functioning (e.g. shopping, managing finances, job skills). Thus, interventions to improve cognitive abilities are needed to enhance psychosocial function and overall quality of life.

Some cognitive deficits, such as problems with working memory, are apparent even in the early stages of the disease. Working memory (WM) is the ability to actively maintain and manipulate information in one's mind and is needed for many complex tasks such as learning, communication and problem-solving . Individuals with PD often show deficits in both WM maintenance (e.g., holding a phone number in mind to make a call) and manipulation (e.g.,mental calculation at the grocery store checkout) skills, depending upon the stage of the disease and progression of damage to frontal-subcortical circuits. Attempts to identify pharmacological agents that ameliorate cognitive dysfunction have been largely unsuccessful or associated with undesirable side effects (e.g. Vale, 2009).

The investigators propose that specific cognitive training to improve WM could provide direct benefit to psychosocial function of PD patients; it could potentially enhance any positive benefits or reduce the negative effects of pharmacological treatment without an added risk of side effects as well. Promising interventions focused on intensive and direct WM training are emerging and have been shown to generalize to other cognitive domains, such as fluid intelligence.

Cognitive training has been successful in patients with traumatic brain injury, who also show WM deficits as a result of damage to frontal-subcortical circuits. In addition, successful WM training is associated with changes in dopamine receptor density as well as changes in patterns of neural activity in task-relevant areas of the brain. To date, a limited number of small group studies provide preliminary evidence that some aspects of cognitive function can be enhanced by training in PD patients also receiving dopaminergic therapy, although few use control groups to account for potential repeated testing practice effects.

• Behavioral: Adaptive working memory training task

  The working memory training task will consist of an adaptive working memory computer program that will test and extend patients' working memory capacity.

  Adaptive refers to the increase in the number of items that the patient is required to remember.

• Behavioral: Non-adaptive working memory training task (i.e. an active control task)
  Active control task will consist of a non-adaptive working memory task.
• Behavioral: No training
  No training during the experiment.

• Experimental: Early training
  The early training group will consist of 10 randomly assigned participants who will begin the adaptive working memory training task immediately after baseline assessment. They will continue training for 5 weeks, after which they will continue for 5 weeks using a non-adaptive working memory task (active control task).
  Interventions:

  • Behavioral: Adaptive working memory training task
  • Behavioral: Non-adaptive working memory training task (i.e. an active control task)
• Experimental: Late training group
  The late training group will engage in an active, but non-adaptive training working memory task (i.e. the active control) immediately after baseline assessment for 5 weeks. After the initial 5 weeks of the active control task they will then switch to the adaptive working memory task for 5 weeks.
  Interventions:

  • Behavioral: Adaptive working memory training task
  • Behavioral: Non-adaptive working memory training task (i.e. an active control task)
• Placebo Comparator: No training group
  The no training group will engage in no training over the course of the pilot study, but will still participate in baseline, 5 week, 10 . This will allow us to determine if changes in the outcome and assessment variables are due to the working memory training or progression in the disease itself.
  Intervention: Behavioral: No training

Inclusion Criteria:

• clinical diagnosis of idiopathic Parkinson's disease
• self-reported concerns about their working memory, or working memory deficits that were identified by a clinical examination
• be classified as Hohn & Yahr Stage 1 or 2
• be receiving a stable dose of dopaminergic therapy

Exclusion Criteria:

• presence of dementia or other significant neurological or psychiatric conditions, as determined by clinical history
• Classification as Hohm & Yahr Stage 3 or 4
• Not on a stable dos of dopaminergic therapy