Transcranial Direct Current Stimulation Enhances Cognitive Training in Parkinson’s Disease

PORTLAND, OR—Combining trans­cranial direct current stimulation (tDCS) and cognitive training resulted in an improvement in a greater number of cognitive outcomes than either intervention alone in a small, randomized, controlled trial of patients with Parkinson’s disease and mild cognitive impairment.

Researchers at Curtin University in Perth, Australia, conducted the trial comparing the effects of standard (ie, not individualized) cognitive training (SCT), tailored (ie, individualized) cognitive training (TCT), tDCS, and a combination of tDCS with either form of cognitive training on cognitive outcomes, activities of daily living, and quality of life. Previously, it was not known whether either form of cognitive training, tDCS, or a combination of the two would be most efficacious in improving cognition.

“Executive function, attention and working memory, memory, and language were the cognitive domains that improved for some groups, and we also found that activities of daily living and quality of life improved for the different groups as well,” PhD candidate Blake Lawrence said at the Fourth World Parkinson Congress.

Patients had cognitive deficits that did not interfere with functional independence and were responding to stable doses of antiparkinsonian medication. Forty-two eligible participants underwent neuropsychologic testing at baseline and were randomly and equally assigned to one of the following six groups: SCT, TCT, tDCS, SCT+tDCS, TCT+tDCS, or control.

Cognitive training consisted of three 45-minute sessions per week for four weeks using Smartbrain Pro software in participants’ homes. tDCS involved constant 1.5-mA stimulation for 20 minutes in one session per week for four weeks at the university, with the anode placed over area F3 to stimulate the left dorsal lateral prefrontal cortex. Neuropsychologic testing was conducted post intervention (ie, at five weeks). Follow-up evaluations were at 12 weeks.

The researchers administered tests to evaluate executive function (Stockings of Cambridge), attention and working memory (Stroop test), memory (paragraph recall), quality of life (Parkinson’s Disease Questionnaire), activities of daily living (Unified Parkinson’s Disease Rating Scale-II), and language (similarities test). In general, combining tDCS with either form of cognitive training resulted in significantly greater improvements in more outcomes than any of the modalities alone. SCT showed positive results when compared against the control group in memory improvement at follow-up (effect size, 1.30), as well as in quality of life and activities of daily living post intervention (effect sizes, 0.24 and 0.33, respectively). TCT showed benefits on quality of life at both time points (effect sizes, 0.26 and 0.12, respectively).

When combined with tDCS, SCT produced improvements in attention and working memory both post intervention and at 12-week follow-up (effect sizes, 0.60 and 0.24, respectively), and executive function at post intervention and follow-up (0.41 and 0.23, respectively). Improvement in activities of daily living and language were statistically significant only immediately post intervention.

Combining tDCS with TCT resulted in improvements post intervention and at follow-up on measures of memory (1.36 and 1.75, respectively) and executive function (0.19 and 0.92, respectively), as well as in language post intervention (1.06).

“The groups that completed both cognitive training and brain stimulation improved to a greater extent and in more outcomes than the groups that just completed the brain training or the stimulation individually,” Mr. Lawrence said. “The majority of the effects were shown immediately after the intervention, but some of the promising results ... actually maintained improvement at the 12-week follow-up, so that was after about eight weeks, when they did not complete any intervention whatsoever.”

The improvements are probably clinically meaningful to patients, since they themselves reported the outcomes on quality of life and activities of daily living scales, he said.

—Daniel M. Keller

PORTLAND, OR—Combining trans­cranial direct current stimulation (tDCS) and cognitive training resulted in an improvement in a greater number of cognitive outcomes than either intervention alone in a small, randomized, controlled trial of patients with Parkinson’s disease and mild cognitive impairment.

Researchers at Curtin University in Perth, Australia, conducted the trial comparing the effects of standard (ie, not individualized) cognitive training (SCT), tailored (ie, individualized) cognitive training (TCT), tDCS, and a combination of tDCS with either form of cognitive training on cognitive outcomes, activities of daily living, and quality of life. Previously, it was not known whether either form of cognitive training, tDCS, or a combination of the two would be most efficacious in improving cognition.

“Executive function, attention and working memory, memory, and language were the cognitive domains that improved for some groups, and we also found that activities of daily living and quality of life improved for the different groups as well,” PhD candidate Blake Lawrence said at the Fourth World Parkinson Congress.

Patients had cognitive deficits that did not interfere with functional independence and were responding to stable doses of antiparkinsonian medication. Forty-two eligible participants underwent neuropsychologic testing at baseline and were randomly and equally assigned to one of the following six groups: SCT, TCT, tDCS, SCT+tDCS, TCT+tDCS, or control.

Cognitive training consisted of three 45-minute sessions per week for four weeks using Smartbrain Pro software in participants’ homes. tDCS involved constant 1.5-mA stimulation for 20 minutes in one session per week for four weeks at the university, with the anode placed over area F3 to stimulate the left dorsal lateral prefrontal cortex. Neuropsychologic testing was conducted post intervention (ie, at five weeks). Follow-up evaluations were at 12 weeks.

The researchers administered tests to evaluate executive function (Stockings of Cambridge), attention and working memory (Stroop test), memory (paragraph recall), quality of life (Parkinson’s Disease Questionnaire), activities of daily living (Unified Parkinson’s Disease Rating Scale-II), and language (similarities test). In general, combining tDCS with either form of cognitive training resulted in significantly greater improvements in more outcomes than any of the modalities alone. SCT showed positive results when compared against the control group in memory improvement at follow-up (effect size, 1.30), as well as in quality of life and activities of daily living post intervention (effect sizes, 0.24 and 0.33, respectively). TCT showed benefits on quality of life at both time points (effect sizes, 0.26 and 0.12, respectively).

When combined with tDCS, SCT produced improvements in attention and working memory both post intervention and at 12-week follow-up (effect sizes, 0.60 and 0.24, respectively), and executive function at post intervention and follow-up (0.41 and 0.23, respectively). Improvement in activities of daily living and language were statistically significant only immediately post intervention.

Combining tDCS with TCT resulted in improvements post intervention and at follow-up on measures of memory (1.36 and 1.75, respectively) and executive function (0.19 and 0.92, respectively), as well as in language post intervention (1.06).

“The groups that completed both cognitive training and brain stimulation improved to a greater extent and in more outcomes than the groups that just completed the brain training or the stimulation individually,” Mr. Lawrence said. “The majority of the effects were shown immediately after the intervention, but some of the promising results ... actually maintained improvement at the 12-week follow-up, so that was after about eight weeks, when they did not complete any intervention whatsoever.”

The improvements are probably clinically meaningful to patients, since they themselves reported the outcomes on quality of life and activities of daily living scales, he said.

—Daniel M. Keller

PORTLAND, OR—Combining trans­cranial direct current stimulation (tDCS) and cognitive training resulted in an improvement in a greater number of cognitive outcomes than either intervention alone in a small, randomized, controlled trial of patients with Parkinson’s disease and mild cognitive impairment.

Researchers at Curtin University in Perth, Australia, conducted the trial comparing the effects of standard (ie, not individualized) cognitive training (SCT), tailored (ie, individualized) cognitive training (TCT), tDCS, and a combination of tDCS with either form of cognitive training on cognitive outcomes, activities of daily living, and quality of life. Previously, it was not known whether either form of cognitive training, tDCS, or a combination of the two would be most efficacious in improving cognition.

“Executive function, attention and working memory, memory, and language were the cognitive domains that improved for some groups, and we also found that activities of daily living and quality of life improved for the different groups as well,” PhD candidate Blake Lawrence said at the Fourth World Parkinson Congress.

Patients had cognitive deficits that did not interfere with functional independence and were responding to stable doses of antiparkinsonian medication. Forty-two eligible participants underwent neuropsychologic testing at baseline and were randomly and equally assigned to one of the following six groups: SCT, TCT, tDCS, SCT+tDCS, TCT+tDCS, or control.

Cognitive training consisted of three 45-minute sessions per week for four weeks using Smartbrain Pro software in participants’ homes. tDCS involved constant 1.5-mA stimulation for 20 minutes in one session per week for four weeks at the university, with the anode placed over area F3 to stimulate the left dorsal lateral prefrontal cortex. Neuropsychologic testing was conducted post intervention (ie, at five weeks). Follow-up evaluations were at 12 weeks.

The researchers administered tests to evaluate executive function (Stockings of Cambridge), attention and working memory (Stroop test), memory (paragraph recall), quality of life (Parkinson’s Disease Questionnaire), activities of daily living (Unified Parkinson’s Disease Rating Scale-II), and language (similarities test). In general, combining tDCS with either form of cognitive training resulted in significantly greater improvements in more outcomes than any of the modalities alone. SCT showed positive results when compared against the control group in memory improvement at follow-up (effect size, 1.30), as well as in quality of life and activities of daily living post intervention (effect sizes, 0.24 and 0.33, respectively). TCT showed benefits on quality of life at both time points (effect sizes, 0.26 and 0.12, respectively).

When combined with tDCS, SCT produced improvements in attention and working memory both post intervention and at 12-week follow-up (effect sizes, 0.60 and 0.24, respectively), and executive function at post intervention and follow-up (0.41 and 0.23, respectively). Improvement in activities of daily living and language were statistically significant only immediately post intervention.

Combining tDCS with TCT resulted in improvements post intervention and at follow-up on measures of memory (1.36 and 1.75, respectively) and executive function (0.19 and 0.92, respectively), as well as in language post intervention (1.06).

“The groups that completed both cognitive training and brain stimulation improved to a greater extent and in more outcomes than the groups that just completed the brain training or the stimulation individually,” Mr. Lawrence said. “The majority of the effects were shown immediately after the intervention, but some of the promising results ... actually maintained improvement at the 12-week follow-up, so that was after about eight weeks, when they did not complete any intervention whatsoever.”

The improvements are probably clinically meaningful to patients, since they themselves reported the outcomes on quality of life and activities of daily living scales, he said.

—Daniel M. Keller