Frequency is defined as the rate at which the wavelengths that are recorded during the resting phases, activity, and emotional states reach their peak. As an example, a test conducted and published by research Mariko Osaka details how higher-level activities affect the alpha wave shifted once more difficult tasks were assigned. (Osaka, 2007)
Amplitude- This is the upper extent of either a vibration or an oscillation which is normally determined from a state of equilibrium. A good example of this would be a twenty-year study undertaken by Doctor’s Isaac Star and Francis Wood to discover the inherent relation between the amplitude of a group of “healthy” adults and the eventual morbidity rate that occurred at the end of the study. (Star, Wood, 2014)
Examine the alpha and beta waveforms for change between “eyes closed” state and the“eyes open” state.
Does desynchronization of the alpha rhythm occur when the eyes are open?
Desynchronization does occur within the alpha rhythm when the eyes are open due to external stimuli that is not blocked out when the subject’s eyes are closed. With too many factors to take into account it is difficult to establish a set rhythm that occurs when external stimuli are absent.
Does the beta rhythm become more pronounced in the “eyes open” state?
The beta rhythm denotes a higher state of alertness and becomes more pronounced when in the “eyes open” state, but can be observed to be pronounced during deep sleep as well during REM when the eyes are moving rapidly back and forth. This is attributed to “remembering” or retrieving memories.
The amplitude measurements (Stddev) are indicative of how much alpha activity is occurring in the participant. But the amplitude values for beta do not truly reflect the amount of mental activity occurring with the eyes open. Explain
The amplitude of beta rhythms is normally seen to be lower than alpha rhythms. What this means is that while there isn’t any less electrical activity the positive and negative activities are engaged in counterbalance so that electrical activity is lessened. So rather than getting synchronized patterns that are normally seen in the wave-like pattern of alpha waves, one will begin to see desynchronization or what is known as alpha block. Beta waves are attributed to the arousal of the cortex to greater alertness and/or tension. This is normally seen in those who are alert and attentive to external stimuli.
Examine the delta and theta rhythm. Is there an increase in delta and theta activity when the eyes are open? Explain your observations.
Delta and theta rhythms are low in frequency and are not prevalent when an individual is awake save for varying circumstances. Both rhythms are more prominent during sleep, usually after the transition from light to deeper sleeping, as in REM sleep. There are instances though when delta and theta waves will appear when an invidual is awake. Theta waves can occur when there are emotional responses to frustration, but they will occur normally only in brief intervals. Similarly, delta waves will occur from time to time when focused concentration is needed, but this varies from one individual to the next.
Define the following terms:
Alpha Rhythm- Normally one will see alpha rhythm during the times of rest and reflectoin. This type of rate is usually increased when the eyes are closed and relaxed. Alpha rhythm is usually disrupted once the eys are open and external stimlui intrudes. Typical frequency for alpha rhythms is 8-13 Hz.
Beta Rhythm- The activity associated with Beta is normally quick and accounts for much of the waking state of the conscious mind, meaning when an individual is presented with stimuli from the outside world. The normal frequency for beta rhythms is 13-30 Hz.
Delta Rhythm- This type of rhythm is usually the highest of all amplitudes and has the slowest waves. This rhythm is seen only in deep sleep, and can be observed to enact the body’s capacity for healing and growth. The normal frequency for this rhythm is 1-5 Hz.
Theta Rhythm- This type of rhythm isn’t usually seen in adults when awake unless they are experiencing a calm, reflect period. It is very normal in children of heightened alertness and 13 or younger. The frequency for this is normally 4-8 Hz. (Fu Chien Kao, Shin Ping R. Wang, Chih Hsun Huang, Yun Kai Lin, Chih Chia Chen, 2014)
- Frequency
The normal frequency for an alpha rhythm is between 8-13 Hz, so this is indicative of a normally functioning alpha wave. Once a subject’s eyes are opened external stimuli can produce varied and very unreliable results. During periods of rest this is a perfectly normal result for an alpha wave rhythm. External stimuli disrupt such patterns, as do stressful situations. Alpha rhythms are measured in states of relaxation, meditation, and calm. It is important to recognize that a stable environment, devoid of any external stimuli such as sight, sound, or even inward pressures is vital to obtain the necessary results.
II. Questions
- When was the general amplitude of the EEG highest? Why is this?
The amplitude appeared the highest when the subject’s eyes were open, no doubt because of external stimuli.
- When were the alpha wave levels highest and why?
The alpha wave levels were highest when recovering from hyperventilation because of the induced stress to the brain.
- How do your results compare with the information presented in the introduction? Explain any discrepancies.
There is little discrepancy if any between the results and the introduction as both adequately point out what is already seen throughout many different studies. Alpha waves are predominant in a resting adult when the subject’s eyes are closed, and are shown to become disturbed once stimuli of any sort are introduced. In the case of hyperventilation the alpha waves spike and the amplitude increases, disrupting the normal wave form. (Duncan, Spillane, PhD., Morrison, PhD., 2014) While this isn’t a debilitating difference it is enough that it can be deduced that alpha waves are highly subject to any disturbances that can interrupt their normal flow.
- Did the participant need to concentrate during math problems?
The average participant will usually need to concentrate upon a math problem be it simple or complex, but it will vary between subjects. In the matter of such concentration affecting alpha waves it is typically seen that external stimuli can affect the alpha rhythms profoundly, and it is not that different internally. (Bjorkqvist, 2014) Any type of stressor or other type of distraction, whether positive or negative, will be likely to alter the alpha waves in a manner that makes them erratic and fairly unreliable. Requesting a subject to concentrate on mathematics during a testing period will disrupt the alpha rhythm.
- What might account for the amplitude difference of waves recorded from a participant tested alone, in a darkened room, and participants tested in a lab full of students?
The knowledge that someone else is in the room with them can affect a subject’s mood, demeanor, and even internal responses. Also, a variable to consider is how the subject deals with being alone, in the dark, as opposed to those that might experience greater anxiety when around others, particularly faces that are unknown. At the offset there are too many variables to take into account to provide an accurate reading, but likely as not the most affected amongst the rhythms would be the alpha wave levels, as the external stimuli or lack of it could greatly affect the outcome. (Porbadnigk, A.K., 2014)
- Define EEG and provide a brief review of the literature using neurofeedback in a clinical setting for one of the following disorders: ADHD, PTSD, ASD.
EEG stands for electroencephalogram. This is a test that is essentially a recording of the human brain and its varied electrical activity that occur over short periods of time. The time allotted for these tests is usually only 20-40 minutes, and includes the recorded data gathered from multiple electrodes that are placed in various places on the scalp.
- Operant learning strategies can be applied to the modulation of specific brain activity patterns.
Though the rationales have not been proven effective or correct as of yet, it is believed that if they are they will offer a viable solution to ADHD without further medication and with a marked clinical improvement.
While the reliability and methodology are still uncertain, the process is firmly believed to be sound. EEG is a far more acceptable route than medication, which has been known to have adverse side effects in the past. EEG-NF is not the only option that is availabe however, as there are others that are given consideration such as online Tomographic (tNF) which is derived from multichannel scalp EEG, real-time functional magnetic resonance image neuro-feedback (fMRI-NF), or magnotoencephalographic neuro-feedback (MEG-NF). The advantage of tNF is that it targets more regions of the brain, while MEG offers the same advantage without as much prep. Each method has its own advantages and disadvantages but is overall more effective than EEG-NF thanks to the fact that they offer more feedback. Unfortunately they are also far more expensive, though if only a minimum amount of visits are needed they are considered to be a viable option.
When sticking to the standard use of EEG-NF though it is important to stress that a study be held to the same deviations as this can easily disrupt any study being conducted. Whether at rest or engaged in activity, a deviation must be constant. Whether or not EEG-NF is in fact useful in determining the true cause and available treatment for ADHD should be rooted out by utilizing an optimal learning setting based on the technical level of EEG-NF and with respect to the learning abilities inherent within daily life. (Vollebregt, Boomsma, Willemse, Buitelaar, 2014)
In conclusion EEG is a valuable tool and an effective method of treating and/or discovering the pathophysiology of various disorders, but the cost no doubt turns many people away unless there is no other option. It’s value cannot be so easily diminished as the inherent importance behind the significance of rhythm patterns can tell researchers and scientists a great deal concerning the human brain, not the least of which is how it works and what effects it most. Undoubtedly it is a great contribution to science that still has a large number of uses to be fully utilized and catalogued.
References
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Fu Chien Kao, Shin Ping R. Wang, Chih Hsun Huang, Yun Kai Lin, Chih Chia Chen. (2014)
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Osaka, Mariko. (2007) Peak Alpha Frequency of EEG during a Mental Task: Task Difficulty and
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Porbadnigk, A.K. (2014) When brain and behavior disagree: Tackling systematic label noise in
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