Walking while simultaneously carrying out a cognitive task, like talking on a cellphone or with a companion, happens frequently throughout the day for many of us. The concurrent performance of two tasks requires the ability to split attention. For older people, difficulties performing another task while walking or standing reflect an existing and/or a potential problem concerning both functions. It also means an increased risk of falling, which can have many severe and undesirable consequences for older adults.
Tel Aviv University researchers sought to examine the benefits of very low intensity, non-invasive electrical stimulation of various parts of the brain, on the capability of older adults to walk or stand while simultaneously carrying out a cognitive task, a common dual-task situation that can determine their overall functionality. They hoped that this might improve their ability to perform both tasks simultaneously in a safer manner. The researchers found that when stimulating the dorsal lateral pre-frontal cortex (DLPFC), a cognitive brain area responsible for dividing attention and executive functions, the immediate, negative impact of a dual-task on standing and walking performance was significantly reduced.
The study team under the leadership of Prof. Jeffrey Hausdorff of the Sackler Faculty of Medicine, the Sagol School of Neuroscience, and the Tel Aviv Sourasky Medical Center (Ichilov), and Dr. Brad Manor at Harvard Medical School, as well as researchers from Harvard University, research and medical institutions in the US and Spain, and the Tel Aviv Sourasky Medical Center (Ichilov). The study was published in the Annals of Neurology, the journal of the American Neurological Association. The research was funded by a grant from the US-Israel Binational Science Foundation.
The study cohort included 57 subjects over the age of 70. Each of them was tested by 4 different treatments:
- Sham, designed not to have any influence at all, but to rule out any placebo effects;
- Stimulation of a cognitive area of the brain (DLPFC) that is responsible for dividing attention;
- Stimulation of a sensory-motor area of the brain which contributes to the regulation of walking;
- Simultaneous stimulation of both areas – motor and cognitive – together.
Each treatment included non-invasive stimulation using a very low-intensity electric current for 20 minutes. Immediately upon the conclusion of the treatment, the walking and standing sway of each subject were evaluated, with and without the request to also perform a cognitive task.
The study showed that stimulation of the cognitive area, whether alone or together with the stimulation of the motor area, reduced the negative effects of the cognitive task on walking and standing stability by about 50%. Stimulation of the sensory-motor area alone and sham stimulation did not improve the subjects’ performance. The researchers explain that, since the stimulation is gentle, it does not activate brain neurons but only increases their excitability; in other words, it facilitates the ability of the patient to activate those neurons in his or her brain.
“In our study, we demonstrated that a low-level, gentle stimulation of a specific cognitive area of the brain can improve the performance of older adults when they carry out the double task of walking or standing in place while at the same time performing a cognitive task, at least within the immediate time range,” says Prof. Hausdorff.
“We hope that a series of treatments will lead to similar positive results over a more protracted period: to improve standing stability and walking capability, diminish the risks of falling, and perhaps also enhance cognitive function among the elderly population. This treatment is safe, and we hope that, in time, people will be able to undergo self-treatment in their own homes. Additionally, we foresee the possibility of combining this type of therapy with exercise and other modes of intervention that can help to improve walking, to enhance thinking, and to reduce the risk of falls. There is evidence that combined therapy could prove to be the most effective solution, but further research is required to examine this,” he concludes.