The Need for Big Data and Large Consortiums on The Use of EEG as a Potential Tool to Decide on Which Frequency We Should Use for Sensory Entrainment in Alzheimer’s Disease?

Abstract

AbstractBackgroundSuccessful use of sensory 40 Hz‐gamma entrainment has been shown in Alzheimer’s Disease animal models. Few studies had used 40 Hz‐gamma sensory gamma entrainment on human subjects and there are contradictory results on these studies. We think there could be different frequency dynamics in animals and in humans. To answer this question, we aimed to analyze the dominant gamma frequency band in Alzheimer’s Disease patients, healthy young and elderly subjects. We hypothesized that the dominant gamma frequency would be different across groups being lower in AD patients.MethodEyes open and eyes closed spontaneous EEG data of 179 participants ( 59 early‐stage AD patients, 60 healthy elderly, and 60 healthy young subjects) were analyzed. Fast Fourier Transform (FFT) was applied to eyes open and eyes closed data separately. The three highest peaks of power value as the gamma dominant peak frequency were analyzed.ResultsThe results indicated that the gamma dominant peak frequency of AD patients (Mean eyes opened = 33.4 Hz, Mean eyes closed = 32.7 Hz) was lower than healthy elderly (Mean eyes opened = 35.5 Hz, Mean eyes closed = 35.0 Hz) and healthy young subjects (Mean eyes opened = 37.2 Hz, Mean eyes closed = 37.0 Hz) (p< 0,05). Furthermore, the healthy elderly group had lower gamma dominant peak frequency values than the young healthy group (p< 0,05).ConclusionThe results of the present study showed that the dominant gamma frequencies are being slower as the age increase, moreover it is even getting slower in AD patients. The dominant gamma frequency of healthy elderly age is 35 Hz for eyes closed and 35.5 Hz for eyes‐open conditions. Since the AD patients had a 32.7‐33 Hz gamma frequency range it would be adequate to use 35 Hz gamma entrainment as the dominant frequency of the healthy elderly group to normalize the slower gamma frequency band in AD patients. So rather than 40 Hz, gamma entrainment 35 Hz gamma entrainment could be more beneficial for AD subjects. To test this hypothesis, a global consortium is needed to find out the right gamma frequency in large subject groups.