BBPK 407 - Electroencephalogram Theory (pages 145-150, 166-168) & HRV Theory

What does EEG Measure?, What unit does it measure this in?

Measure the voltage fluctuations in ionic current from neurons within the brain

- Summation of EPSPs and IPSPs

- Microvolts

What are brain waves?

Small electrical signals output by the brain continuously

What is EEG most commonly used to diagnose?

- Epilepsy

- Sleep Disorders

*- Stroke

*- Tumors

*- Other Focal Brain disorders

What are the frequencies of different brain waves? (5)

- Gamma = >30Hz

- Beta = 14-30Hz

- Alpha = 8-13Hz

- Theta = 4-7Hz

- Delta = 1-3Hz

What is an alpha block?

Occurs when a subject has their eyes closed and is quickly drawn to performing a mental task.

- Alpha waves drop/stop while beta waves increase

- Exists with high cortical arousal

How can meditation impact EEG wave activity?

- Can increase the alpha wave activity during meditative states

- Can decrease alpha wave activity during mind wandering states.

What are the hemispheres of the brain responsible for?

Left specialized for language processing

Right specialized for visuospatial processing

What are the ranges for PSD? (4)

- ULP: Ultra low frequency range = <0.003Hz

- VLP: Very low frequency range = 0.003-0.04Hz

- LP: Low frequency range = 0.04-0.15Hz

- HP: High frequency range = 0.15-0.4Hz

What are the PSD ranges indicative of? (4)

- ULP = Sudden Cardiac Death

- VLP = Thermoregulation, RAS, PA

- LP = Sympathetic activity (baroreceptor modulation)

- HP = Vagal activity and respiration

How does stress impact your power spectrum density?

- Increases Low power

- Decreases High power

What are normal ranges for HRV ratio?

Between 0.8 and 1.5

How does hypertension impact HRV ratio?

- Significantly increases their LP value

- Decreases HP value

How does diabetes impact HRV ratio? (3)

- Decreases R-R variance with a smaller interval

- Normal PSD at rest

- Diminished response to increase LP and decrease HP during standing or tilted postures.

How does smoking impact HRV ratio?

- Higher LP values

- Lower HP values

What are some applications of neuralink?

Stimulate and record brain activity, intended to have medical applications in treating spinal-cord injuries and neurological diseases

What type of brain activity occurs with delta waves? (2)

- Deep sleep

- Increased concentration with internal working memory

What type of brain activity occurs with Theta waves? (3)

- Memory encoding and retrieval

- Cognitive workload (recall)

- Increased fatigue levels

What type of brain activity occurs with Alpha waves? (2)

- Closed eyes calmed state

- Relaxed wakefulness

What type of brain activity occurs with Beta waves? (3)

- Planning/executive movement of the body

- Observing bodily movement of others

- "Mirror" Neuron system activates

What type of brain activity occurs with Gamma waves? (3)

- Attentive focusing?

- Data exchange between brain regions?

- REM?

What major physiological factors are associated with HRV? (3)

- Oscillatory fluctuations in BP

- Frequency of oscillations due to thermal regulation

- Respiration

Define HRV

The changes in time intervals between consecutive heartbeats (analysis of variability in R-R intervals)

What are the time domain method for measuring HRV?

- SDNN: standard deviation of NN internals

- RMSSD: Root mean squat of successive differences between adjacent NNs

- NN50: Number of pairs of successive NNs that differ by more than 50 ms

What are the frequency domain methods for measuring HRV?

Power Spectral Density: Fast Fourier transform

What can LF:HF be used for? (3)

- Good indicator of sympathetic-vagal balance

- HF represents Vagal Activity

- LF represents Sympathetic activity

Explain the ways to measure/monitor heat rate?

- Electrical (polar chest strap emitter and receiver watch)

- Optical (Potoplethysmography watches)

When are heart rate monitoring tools less accurate (3)

- Optical During strenuous activity

- Optical lag with HR display (abrupt changes)

- Optical less accurate for measuring HRV