An interesting body of scientific work exists to investigate the question of whether or not various forms of electromagnetic stimulation can improve tissue function, particularly in older people. To improve neurogenesis in an aging brain, or enhance nerve regrowth following injury, for example. Taken broadly, the manipulation of cells to specific ends via electromagnetism is far less studied than is the case for the use of small molecules, however, and this is very evident in the character of the data.
Picking any one approach to electromagnetic therapy at random, one tends to find unpromising results, when taken as a whole, meaning a few flashes of claimed success amidst a great deal of failure. There is reason to believe that the fine details of equipment, experimental setup, duration of treatment, and frequency of electromagnetic radiation are all important, and that perhaps consistent success is a matter of finding the right combination for a given application. That may or may not be the case.
Transcranial direct current stimulation has the merit of having perhaps fewer important variables to adjust in terms of how the treatment is delivered, which might explain why the data looks somewhat better for this approach than for others I've seen. That is a low bar, but still. Today's open access paper provides a review of the literature on this topic, which at the end of the day suggests that some approaches can beneficially affect at least some functions in the aging brain. Considerable uncertainty remains.
Transcranial direct current stimulation (tDCS) is a non-invasive tool for neuromodulation that has proven to be well-tolerated and safe. This technique employs low-intensity continuous or galvanic current applied transcutaneously via electrodes placed on the scalp. The change generated in the electric potential of the membrane of the underlying neurons affects neuronal excitability, which varies depending on the orientation of the electric field determined by the position and polarity of the electrodes. This effect on excitability is believed to be related to transient changes in the synaptic efficiency of different neurotransmitters.
Complex structural and functional changes in the brain are some of the processes related to normal aging that entail deterioration of cognitive, perception, and motor capacities, which affects daily life activities, independence, and quality of life. The main finding observed is the increase in dual-task costs, and the most affected ability due to aging is the simultaneous execution of one motor and one cognitive task. Additionally, older adults present a reduction in the structural and functional plasticity of the brain and in flexibility for tasks requiring previous learning. Trials using neuroimaging indicate that the left dorsolateral prefrontal cortex (DLPFC), which intervenes in the executing function, is one of the key brain regions involved in performing combined cognitive and motor tasks under dual-task conditions. For this reason, tDCS interventions designed for facilitating the functional activation of the DLPFC and its neuronal networks could improve the cognitive function and motor performance in the elderly.
This systematic review aimed at compiling and summarizing the currently available scientific evidence about the effect of tDCS on functionality in older adults over 60 years of age. A search of databases was conducted to find randomized clinical trials that applied tDCS versus sham stimulation in the above-mentioned population. No limits were established in terms of date of publication. A total of 237 trials were found, of which 24 met the inclusion criteria. Finally, nine studies were analyzed, including 260 healthy subjects with average age between 61.0 and 85.8 years. Seven of the nine included studies reported superior improvements in functionality variables following the application of tDCS compared to sham stimulation. Anodal tDCS applied over the motor cortex may be an effective technique for improving balance and posture control in healthy older adults. However, further high-quality randomized controlled trials are required to determine the most effective protocols and to clarify potential benefits for older adults.