Brain waves are electrical impulses in the brain. They are at the root of all our behaviors, emotions, and thoughts. When the brain is working, the communication between masses of neurons discharges electric impulses. These impulses are electromagnetic waves that can be measured by electroencephalography (EEG)⁽³⁾.These waves vary from fast to slow frequency, and high to low amplitude according to the activity level of the brain. All wave types are always present but one normally predominates (according to the brain’s activity level)⁽¹⁾.
However, as we age, these brainwaves, especially gamma waves, begin to decline. This decline in brainwaves, which occurs even in healthy aging individuals(7), may be an early warning sign of cognitive decline. Observing changes in electrical activity may also allow researchers to gain a better understanding of how neurological and psychiatric disorders develop over time and how they can be prevented using novel therapeutics.
5 TYPES OF BRAIN WAVES FREQUENCIES
GAMMA (20 – 50 HZ)
The highest in frequency, and smallest in amplitude of all brain waves. Predominantly present in sensory and perception processes, attention, and memory encoding/retrieval (encoding=storage / retrieval=remembering)⁽²⁻³⁾.
BETA (13 – 38 HZ)
Low amplitude and fast/high frequency. Leading waves when the brain is alert, active and engaged in intellectual tasks. Examples of activities when Beta waves are predominant: Active conversation, focused work, teaching⁽¹⁾.
ALPHA (8 – 12 HZ)
Larger in amplitude and slower frequency compared to Beta waves. Mostly present when the brain is relaxed or in a resting state. Examples of activities when Alpha waves are predominant: taking a rest after finishing an intellectual activity. Closing the eyes and picturing relaxing situations⁽¹⁾.
THETA (4 – 7 HZ)
Increased amplitude and decreased frequency in comparison to Alpha waves. Mostly present in high states of mental relaxation. When Theta waves are predominant, the brain could be placed in the in-between of being awake and asleep. Activities when leading waves are Theta: daydreaming, situations when a person notices that they performed an activity without being conscious of it, like driving or running without remembering the last couple of kilometers⁽¹⁾.
DELTA (1 – 3 HZ)
Delta are the brainwaves with the highest amplitude and lowest frequency. They are predominant in deep sleeping states.
Brainwaves & Diseases associated with BND
As mentioned in the previous blog post, different diseases are observed when neurons are not firing in synchrony, resulting in Brain Network Dysfunction (BND). Similarly, it has been shown in some cases of BND, that the brainwaves discharged are altered⁽³⁾. For example, gamma waves (ranging between 20-50 Hz), involved in memory and attention processes, are disrupted in patients with Alzheimer’s disease (AD). Studies indicate that the alteration of electrical impulses begin before changes in the brain, aligned with observations pointing to pathological processes in AD initiating years, even decades before symptoms appear⁽³⁻⁴⁾.
Considering that brain rhythms are altered in brain diseases, it has been hypothesized that restoring them could have a preventative or therapeutic effect in diseases with BND.
To test this, researchers at MIT conducted a study in which they successfully synchronized mice’s gamma waves by exposing them to a 40 Hz flashing light, resulting in improved memory and beneficial changes in the brain⁽⁵⁾. Later, they conducted a trial using a similar approach, exposing Alzheimer’s Disease patients to stimulus at 40 Hz (light and sound) one hour daily for 6-9 months. It was established after 6 months that participants in the treatment group showed (in comparison to placebo group):
- 84% slowdown of functional decline (ADCS-ADL score)
- 83% decrease in memory and cognitive decline (MMSE score)
- 61% reduction of brain atrophy and loss of brain volume ⁽³⁻⁴⁾
The results of these studies opened the possibility of exploring novel treatment approaches for neurological diseases with BND based on the basic rhythms of the brain. These unconventional procedures seem to be a promising, non-invasive alternative to drug-based treatments, that so far have proven unsuccessful⁽³⁾.
At Optoceutics, we are working at the corner of innovation, technology, and machine learning to further deepen our understanding on how restoring BND may induce beneficial effects on individuals suffering from disorders not only associated with neurodegenerative disease but also psychological disorders such as anxiety, depression, and Adult ADHD. Our technology is proven safe to use with little to no side effects in our initial clinical trials. Currently, we are conducting our section clinical trials in patients with Alzheimer’s disease and are excited to be part of the group of researchers exploring and working on the development of novel therapies for AD and other diseases associated with BND. If you want to know more about our research, technology, or be part of our journey, you are welcome to contact us.
- Scientific American (1997, Dec 22) What is the function of the various brainwaves?. Link
- Alzforum (2021, Apr 14) Does Synchronizing Brain Waves Bring Harmony? Link
- Alzforum (2016, Dec 7) Flashy Treatment Synchronizes Neurons, Lowers Aβ in Mice Link
- Jack Jr, C. R., Bennett, D. A., Blennow, K., Carrillo, M. C., Dunn, B., Haeberlein, S. B., … & Silverberg, N. (2018). NIA‐AA research framework: toward a biological definition of Alzheimer’s disease. Alzheimer’s & Dementia, 14(4), 535-562. Link
- Iaccarino, H. F., Singer, A. C., Martorell, A. J., Rudenko, A., Gao, F., Gillingham, T. Z., … & Tsai, L. H. (2016). Gamma frequency entrainment attenuates amyloid load and modifies microglia. Nature, 540(7632), 230-235. Link
- Businesswire (2021, March 17) Cognito Therapeutics to Advance Digital Therapeutic for Alzheimer’s into Pivotal Studies Based on Positive Clinical Results Announced at AD/PD 2021 Link
- Dinavahi V.P.S. Murty Keerthana Manikandan Wu padrasta Santosh Kumar Ranjini, Garani Ramesh Simran, Purokayastha Mahendra Javali Naren Prahalada RaoSupratim Ray, Gamma oscillations weaken with age in healthy elderly in human EEG, Center for Neuroscience, Indian Institute of Science, NeuroImage 215, 2020, 116826. Link