I came across an review article on the topic of physical exercise for the modulation of mild cognitive impairment.
The introduction in the paper cited that mild cognitive impairment (MCI) is a precursor of dementia, including Alzheimer Disease. Did you know that 42% of 85-year-olds have mild cognitive impairment? Furthermore, it has been estimated that a 25% increase in activity levels would prevent 1 million cases of Alzheimer Disease.
Cortical evaluation can be measured by different tools, such as functional magnetic resonance imaging and electroencephalogram (EEG), but also with other tools associated with behaviour. EEG studies look at the brain waves. “Results on resting-state EEG consistently indicated increases in low-frequency power bands (delta: <4Hz; theta: 4-8Hz), decrease in high-frequency power bands (alpha: 8-12 Hz; beta: 12-22 Hz), and decrease in synchronization. Because EEG activity is altered in patients with MCI and physical exercise is associated with improvements in cognition, it is crucial to identify the scientific evidence supporting a potential effect of physical exercise on EEG activity in individuals with MCI."
There has been an influx of studies that look at preventing a decline in cognition via physical exercise, and using EEG as a measure of cortical activity. The paper in question found 365 potential studies that whittled down to 7 that met the inclusion criteria.
Of the 7 studies included, the physical activity interventions included, 1) Exergame (virtual game that included physical exercise), 2) Aerobic exercise (via treadmill and/or stationary bike), 3) Resistance training (via exercise bands, weight training, balance exercises), 4) A combination of all. It should be noted that 4 of the studies also incorporated some cognitive training as well.
Six of the studies looked at the chronic effects (i.e. the exercise sessions took place over a 6 – 12 week time frame and ranging from 2 days per week to 6 days per week, whereas one study looked at the acute effects of one bout of exercise.
What were they looking for?
Studies have suggested that MCI causes resting-state EEG signals to “slow down,” corresponding to an increase of power in low-frequency bands (delta, theta) and a decrease of
power in higher-frequency bands (alpha, beta). The earliest modifications of EEG signals of patients with MCI occur in the beta and theta bands, whereas changes in the alpha and delta
appear later, specifically in patients with AD.
And a brief run down on brain-waves:
- Delta rhythm (<4Hz) reflects a gloval state of cortical dafferentation and is increased in patients with MCI.
- Theta rhythm (band 4-8 Hz) is linked to focusing, attention, mental effort, and stimulation processing.
- Alpha rhythm (8-12 Hz) is associated with higher brain functions, such as working memory and mental representation of objects. The alpha 3/alpha 2 power ratio is higher in persons with MCI than controls, indicating atrophy.
- Beta rhythm (8-12 Hz) is related to attention and vigilance and is decreased in individuals with MCI.
In conclusion, physical exercise induces positive changes in cortical activity and cognition in individuals with MCI.
- In resting-state EEG recordings, the acute effects of exercise included a decrease in the power of delta and theta rhythms as well as increase in EEG complexity. These alterations indicate an improvement in cortical activity in individuals with MCI immediately after an exercise bout.
- Engaged in a 6- to 12-week chronic program of exercise seems to lead to a reduction in the power of delta and theta rhythms, an increase in the power of beta and alpha rhythms, and an increase in EEG complexity and connectivity. These alterations indicate that exercise improves cortical activity in individuals with MCI.
Taking it to the dogs…
I couldn’t find any research studies on canine cognitive dysfunction and exercise specifically. However, the parallels between canine cognitive dysfunction and Alzheimer’s is remarkable. Many nutritional studies cross the species boundaries on this topic, so why not exercise? I think this is an untapped niche. Exercise classes. Hydrotherapy session. Therapist-led exercise sessions and so on. Canine rehab has a role here as well!
On that note, why not do an educational campaign on the role of exercise on dementia!? And have a great week ahead!
Pedroso RV, Lima-Silva AE, Tarachuque PE, Fraga FJ, Stein AM. Efficacy of Physical Exercise on Cortical Activity Modulation in Mild Cognitive Impairment: A Systematic Review. Arch Phys Med Rehabil. 2021 Dec;102(12):2393-2401.