HIRREM data from assessments or sessions can be displayed several ways. One method is the use of a spectrograph to display electrical frequencies (Hertz, Hz, vertical axis) and amplitudes (microvolts, µv, horizontal axis) recorded from the left and right sides of the brain (left and right half of display, respectively) at specific locations during an epoch of time (i.e. one minute with eyes closed during an assessment). Below are examples of spectrographs obtained during the HIRREM assessment on several research subjects enrolled in the Developmental Study (Figure 6A, 7A, 8A). These pre-HIRREM assessments from the temporal regions (T3/T4, eyes closed) demonstrate several different baseline patterns, including one subject with right side dominance in high frequencies (6A), one with left side dominance in high frequencies (7A), and one with no imbalance, but with excess amplitudes in the very low frequencies (8A).
As mentioned above in the About HIRREM section, right side dominance at high frequencies in the temporal region appears to correlate with a sympathetic dominant pattern, i.e. fight or flight response (Craig AD, Trends Cogn Sci, 2005), while left side dominance at this location appears to correlate with a parasympathetic pattern, i.e freeze or withdrawal response. Bilateral excess amplitude in the very low frequencies appears to correlate with inefficient executive function, focus, and clarity (Barry RJ, et al., Clin Neurophysiol, 2003).
As individuals move through the HIRREM process, the brain patterns will typically shift towards greater balance and quieting of amplitudes. Examples of these types of changes in several subjects enrolled in the Developmental Study are shown below (Figure 6B, 7B, 8B). Every person is unique, and responds to HIRREM differently. There is also not a population-based “normal” brain pattern that is ideal, or most efficient for everyone. These examples are included to graphically illustrate the types of changes described in narrative form above.
Figure 6 A-B: Data from a female teenager enrolled due to autonomic dysfunction, manifesting with frequent nausea, obtained at T3/T4 with eyes closed, before HIRREM, and from the 13th HIRREM session. This subject had a total of 14 HIRREM sessions. At baseline (6A) the most prominent feature in the spectrograph is greater amplitudes in the higher frequencies on the right (110% right dominant in the 23-36 Hertz range at T4). At the 13th HIRREM session (6B) there has been balancing (now 10% left dominant in the same frequency range) and quieting (from 2.48 microvolts on the right in that range at baseline, to 0.44 microvolts at the same location and eye state).
Figure 7, A-B: Data from a 52 year old woman enrolled for insomnia, stress, and anxiety, obtained at T3/T4, with eyes closed, before HIRREM and at the 14th HIRREM session. This subject had a total of 14 HIRREM sessions. At baseline (7A) the most prominent feature is greater amplitudes in the higher frequency ranges on the left (106% left dominant in the 36-55 Hertz range at T3). At the 14th HIRREM session (7B) there has been balancing (now 7% left dominance in the same range) and quieting (from 1.33 microvolts in that range at baseline, to 0.42 microvolts at the same location and eye state).
Figure 8, A-B: Data from a 63 year old male enrolled for insomnia, with poor focus and concentration, obtained at T3/T4 with eyes closed, before HIRREM, and from the 10th HIRREM session. This subject had a total of 10 HIRREM sessions. At baseline (8A) the most prominent feature is excess amplitudes (just over 9 microvolts in the very low frequency ranges bilaterally, without important side difference). At the 10th HIRREM session (8B), there has been overall quieting of amplitudes bilaterally, most obvious in the very low frequencies (now less than 2 microvolts in the same frequency ranges at the same location and eye state).