More Years of Schooling Linked to Better Response to DBS in Small Study

The more years of formal education that people with Parkinson’s disease have, the better they seem to respond to deep-brain stimulation — as seen in a greater ability to “dual-task,” or engage in higher-level thought while walking, a study suggests.

“Education level affects dual-task gait after deep brain stimulation in Parkinson’s disease” was published in the journal Parkinsonism & Related Disorders.

Dual-tasking (DT) measures an individual’s ability to carry out a cognitive task (such as counting, or naming words that start with a particular letter) while engaging in a motor skill like walking. As such, it can be a helpful proxy for clinically relevant measures of a patient’s ability to perform everyday life tasks, which rarely come one at a time. Cognitive and motor skills are both impacted by Parkinson’s, and having to move while thinking a bit can increase the risk of falls.

Deep brain stimulation (DBS) is a surgical treatment for Parkinson’s that involves implanting a device to stimulate targeted regions of the brain with electrical impulses generated by a battery-operated neurostimulator.

Previous studies on DBS have yielded conflicting results about whether this intervention can improve dual-tasking. The researchers behind this study wondered if this conflict exists because DBS improves dual-tasking in some people with Parkinson’s, but not for others.

They recruited 34 people with Parkinson’s (average age 60.5, 44% female) and measured their DT-related gait changes a few months before DBS and again a year after DBS.

Based on these measurements, participants were divided into two groups: 18 were “responders,” meaning they had significant improvements for four dual-task assignments at the second measurement (i.e., forward and backward counting, and phonemic and semantic fluency); the remaining 16 were “non-responders” who showed no such improvement.

Cognitive reserve — the brain’s ability to improvise and find alternate ways of preforming a task — can account for differences between individuals in “susceptibility to age- or pathology-related brain changes” and has been studied in Alzheimer’s disease. Importantly, in Parkinson’s disease, higher cognitive reserve is associated with milder cognitive and motor deficits.

Education is known to contribute to cognitive reserve. As such, the researchers also divided the participants based on the highest education level they had completed: primary (through 8th grade), secondary (high school), or ‘high level’ (baccalaureate/university studies of up to 12 years).

Among the 16 non-responders, seven had completed a primary education level, four a secondary, and five had a high level. Among the 18 responders, one had completed primary level schooling, eight secondary, and nine had university level.

Responders were more likely to have completed more years of formal education, with further analyses showing that this association was statistically significant.

Other factors analyzed — including levodopa dose, Unified Parkinson Disease Rating Scale (UPDRS) score, and measurements of cognitive function and memory — were not significantly different between the two groups.

“Educational status affects DT-related gait changes one year post-DBS in [Parkinson’s disease],” the researchers concluded, noting that “a high [cognitive reserve] could be considered as a favourable inclusion criterion for future DBS candidates.”