Working memory training increases neural efficiency in Parkinson’s disease: a randomized controlled trial

Abstract

Impairment of working memory and executive functions are already frequently observed in early stages of Parkinson’s disease. Improvements in working memory performance in this cohort could potentially be achieved via working memory training. However, the specific neural mechanisms underlying different working memory processes such as maintenance as opposed to manipulation are largely under-investigated in Parkinson’s disease. Moreover, the plasticity of these correlates as a function of working memory training are currently unknown in this population. Thus, the working memory subprocesses of maintenance and manipulation were assessed in 41 cognitively healthy patients with Parkinson’s disease using a newly developed working memory paradigm and functional MRI. Nineteen patients were randomized to a 5-week home-based digital working memory training intervention while the remaining patients entered a control, wait list condition. Working memory task-related activation patterns and context-dependent functional connectivity, as well as the change of these neural correlates as a function of training, were assessed. While both working memory processes activated an extended frontoparietal-cerebellar network, only the manipulation of items within working memory also recruited the anterior striatum. The intervention effect on the neural correlates was small, but decreased activation in areas relevant for working memory could be observed, with activation changes correlating with behavioural change. Moreover, training seemed to result in decreased functional connectivity when pure maintenance was required, and in a reorganization of functional connectivity when items had to be manipulated. In accordance with the neural efficacy hypothesis, training resulted in overall reduced activation and reorganized functional connectivity, with a differential effect on the different working memory processes under investigation. Now, larger trials including follow up examinations are needed to further explore the long-term effects of such interventions on a neural level and to estimate the clinical relevance to potentially delay cognitive decline in cognitively healthy patients with Parkinson’s disease.

Predicting Working Memory Training Responsiveness in Parkinson’s Disease: Both “System Hardware” and Room for Improvement Are Needed

“…16 The WMT effect on neural correlates investigated with a newly developed WM paradigm and functional MRI was small, but decreased activation in areas relevant for working memory could be observed, with activation changes correlating with behavioral change. 29 Further details are reported in Ophey and colleagues 16 and Giehl and colleagues. 17,29…”

Cognitive Performance and Learning Parameters Predict Response to Working Memory Training in Parkinson’s Disease

“…Details on prior analyses regarding the general efficacy, as well as neural correlates of WM and WMT are reported in Ophey et al [ 11 ], Giehl et al [ 38 ], and Giehl et al [ 39 ]. Table 2 presents the descriptive data for the cognitive domains across baseline, POST, and 3-month FU assessments for the WMT group and the CG.…”

Neural underpinnings of ethical decisions in life and death dilemmas in naïve and expert firefighters

“…This finding may reflect neural adjustment caused by training and/or intensive exposure and repeated exposure which goes hand in hand with the development of coping strategies. It remains an open question whether this difference reflects the concept of neural efficiency which refers to a theoretical construct that comes from the common finding that if individuals become more proficient in a task due to training, they may require fewer cognitive resources, leading to decreased brain activity in those areas associated with task 65 , 66 . Since there were no differences in the Brief-COPE scores between groups, we suggest that this finding indicates that the use of coping strategies has a greater impact at the neural level for the firefighters than for non-firefighters.…”