Transcranial Direct Current Stimulation, Working Memory Training Beneficial in Prodromal Alzheimer Disease

Hanna Lu, PhD, The Chinese University of Hong Kong

Hanna Lu, PhD

According to the results of a 12-week trial presented at the 2019 Alzheimer’s Association International Conference in Los Angeles, California, combined modality of transcranial direct current stimulation and working memory training shows greater domain-specific cognitive enhancements with higher transferability and sustainability than single modality therapy in older adults with prodromal Alzheimer disease.

Led by Hanna Lu, PhD, research assistant professor at the Chinese University of Hong Kong, investigators sought to determine if subjects with mild cognitive decline would benefit from either a single or combined modality of transcranial direct current stimulation over the left temporal cortex and working memory training.

The double-blind, sham-controlled, randomized trial enrolled 201 patients with mild neurocognitive disorder due to Alzheimer disease that were randomly assigned to receive a 4-week intervention of either transcranial direct current stimulation and working memory training (n=69), sham transcranial direct current stimulation and working memory training (n=64), or transcranial direct current stimulation and control cognitive training (n=68).

The primary outcome measure was the change in the score on the Alzheimer’s Disease Assessment Scale Cognitive subscale (ADAS-cog) and memory tests. Follow-up lasted for 3 months.

In the intent-to-treat analysis, cognitive enhancement was demonstrated across the 3 groups after 4 weeks of intervention; cognitive enhancement measured by ADAS-Cog and delayed recall were also observed across the 3 groups after intervention.

When examining the between-group differences, combined transcranial direct current stimulation and working memory training showed significantly superior improvement compared with single-modality groups in delayed recall performance (P =.043, n² =0.036).

The safety profile was similar between groups, with adverse effects including skin lesions occurring in 2.2% of the subjects.

While single modality, either transcranial direct current stimulation or working memory training, is a safe, feasible, and effective treatment for older adults with prodromal Alzheimer disease, researchers demonstrated that combined modality shows greater domain-specific cognitive enhancements with higher transferability and sustainability. According to the investigators, this finding highlights the potential synergistic effect between modalities and should be further studied.

For more coverage of AAIC 2019, click here.

REFERENCE

Lu H, Sau Man Chan S, Chan W, et al. A combination of non-pharmacological interventions for enhancing cognitive functions in prodromal Alzheimer’s disease: A randomized clinical trial. Presented at: 2019 Alzheimer’s Association International Conference. July 14-18, 2019; Los Angeles, CA.