Brain Brightening for elderly using QEEG guided tPBM

EEG frequency and blood perfusion

tPBM is known to increase blood perfusion by stimulating cytochrome c-oxidase in mitochondria. Blood perfusion can be measured with H2O PET, and blood perfusion and EEG frequency are very closely correlated. (Cook, O'Hara, Uijtdehaage, Mandelkern, & Leuchter, 1998) In general, during sleep and high stress, the EEG shows a high delta and high beta, respectively, accompanied by significant perfusion, reflecting large demand of metabolism. In contrast, theta and alpha have significantly reduced perfusion reflecting decreased metabolism, and the aging process is characterized by a slowing of alpha frequency and an increase in theta in EEG. From this perspective, we can say that tPBM has a mechanism to improve aging by increasing blood perfusion.

Entrainment of EEG rhythm with pulsed NiBS(Noninvasive Brain Stimulation)

NiBS is represented by rTMS, tDCS/tACS, and tPBM. For rTMS, activation using 10 Hz and inhibition using 1 Hz is the standard protocol (Lefaucheur et al., 2020) and even for 10 Hz, it is known that rTMS at a frequency around the individual's alpha frequency + 1 is most effective in securing activation, and if the individual's alpha frequency is faster than the rTMS stimulus, activation is less effective. (Roelofs et al., 2021) In the case of tACS, it has been reported to improve symptoms by applying theta-frequency AC stimulation to those with a strong beta EEG pattern and beta-frequency AC stimulation to those with a strong theta EEG pattern. (Del Felice et al., 2019) In the case of tPBM, the use of pulsed light instead of continuous light has been confirmed to produce different changes than continuous light, showing a tendency to shift the EEG spectrum in the direction of the frequency used.(Yao et al., 2021) In tPBM, the use of a very slow frequency of 1 Hz, as in rTMS, has been shown to improve tremor symptoms in Parkinson's and irritability in autism due to strong beta. On the other hand, low/mid beta, between high beta and theta/alpha, is known to be the most optimal frequency range from a perfusion standpoint and is heavily utilized in pulsed tPBM, and the same applies to neurofeedback training, where patients train their own EEG to reach optimal brain rhythms. (Bouny et al., 2022; Campos da Paz, Garcia, Campos da Paz Neto, & Tomaz, 2018) Pulsed tPBMs, unlike continous tPBMs, are thought to produce synchronized firing of neurons and thereby develop EEG rhythm corresponding to those frequency used by pulsed tPBMs, possibly due to light-activated ion channels in neurons in the region that provides the pulsed light. (Hamblin, 2016)

QEEG patterns of ageing and AD MCI

Older adults typically have slightly reduced cerebral blood flow, theta band power increases with age, power in the alpha band decreases slightly, but beta frequency power does not systematically decrease, likely due to compensatory behavior. Decreased 40 Hz band power may serve as a marker of aging. (Budzynski, 2007) This is a well-known aging process. Increased amplitude in the low frequency domain and decreased amplitude in the high frequency domain is a very typical EEG pattern of MCI. (Şeker & Özerdem, 2024) This degenerative process can be well observed through the ratio of theta to beta. (Azami et al., 2023) Meanwhile, alpha-band oscillations reflect one of the most basic cognitive processes and can also be shown to play a key role in the coalescence of brain activity in different frequencies. (Klimesch, 2012) These alpha peak frequencies show a gradual decrease with ageing and degenerative process. A decrease in higher alpha frequencies produced by thalamo-cortical feedback loops leads to a decrease in search and retrieval processes in (semantic) long-term memory. (Klimesch, 1999)

QEEG guided tPBM for AD MCI : Pilot study result

By reversing the aging process, such as decreasing theta, increasing alpha and beta, and increasing alpha frequency, can be utilized as a brain brightening protocol to weaken the EEG pattern of MCI. You can see the pilot study data below where the theta/beta ratio was significantly reduced using QEEG guided tPBM and the alpha peak frequency was increased compared to the control.

Figure 1. Analysis of 53 subjects with mild cognitive impairment who received near-infrared personalized tPBM care for 10 minutes per session, 3 times per week for a total of 8 weeks. Source level TBR2 shows normalization of EEG balance in the frontal and parietal lobes after care.

Figure 2. Pre-post CDR and CDR-SB changes in 23 of the 53 participants in Figure 1 who received an 8-week tPBM intervention followed by a 4-week maintenance intervention. The 8-week intervention consisted of 3 sessions per week and maintenance consisted of 1 session per week. Significant cognitive improvement was seen in the group that received the 8-week intervention followed by 4 weeks of maintenance.

Figure 3. 18 elderly participants were divided into a control group and a PBM care group, which received three personalized PBMs per week for eight weeks. Alpha peak frequency decreased in the control group and increased in the PBM care group, consistent with typical aging patterns.

A candidate personalized tPBM protocol used in the pilot study

The tPBM protocol can be modified to enhance alpha, or speed up the alpha peak frequency, enhance low beta frequencies(the rhythm that occurs when the sensory motor is quiet in a state of calm focus, called sensory motor rhythm) to improve sleep in older adults while providing stable blood perfusion, and add gamma rhythms to address the decrease in brain coherence found in older adults and strengthen networking between brain regions.

EEG phenotype	tPBM protocol	Time
If alpha is weakened	Global Alpha + Global SMR + Gamma	4 min+4 min+2 min
If alpha power is normal but it's slow	Occipital Alpha speed up + Global SMR + Gamma	4 min+4 min+2 min
If theta is strong (frontal, temporal)	Global Alpha + Global SMR + Add the corresponding frontotemporal region beta	3 min+3 min+4 min

Table 1. Tentative protocol. Alpha (9-10 Hz), SMR (13-15 Hz), Beta (16-18 Hz), and Gamma (38-42 Hz), with the frequency of each band being adjustable based on age, the individual's power distribution, and the individual's response.

References

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Bouny, P., Arsac, L. M., Pratviel, Y., Boffet, A., Touré Cuq, E., & Deschodt-Arsac, V. (2022). A Single Session of SMR-Neurofeedback Training Improves Selective Attention Emerging from a Dynamic Structuring of Brain-Heart Interplay. Brain Sci, 12(6). doi:10.3390/brainsci12060794

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Campos da Paz, V. K., Garcia, A., Campos da Paz Neto, A., & Tomaz, C. (2018). SMR Neurofeedback Training Facilitates Working Memory Performance in Healthy Older Adults: A Behavioral and EEG Study. Frontiers in Behavioral Neuroscience, 12. doi:10.3389/fnbeh.2018.00321

Cook, I. A., O'Hara, R., Uijtdehaage, S. H., Mandelkern, M., & Leuchter, A. F. (1998). Assessing the accuracy of topographic EEG mapping for determining local brain function. Electroencephalogr Clin Neurophysiol, 107(6), 408-414. doi:10.1016/s0013-4694(98)00092-3

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