Aberrant EEG

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Aberrant EEG

• Julie Mach, Hieu Nguyen
• Jeff Day

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EEG Biofeedback

• Electroencephalogram monitors brain activity
• Patients learn to control certain functions
• Successful Applications
• ADHD
• Anxiety disorders
• Mood disorders
• Seizure disorders
• Traumatic brain injury
• Addiction

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Aberrant EEG

• Non-invasive procedure
• Direct measure of cortical activity
• May detect brain abnormalities before behavioral
  symptoms appear
• Can monitor changes as diseases progress

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Traumatic Brain Injury

• Symptoms
• Initial loss of consciousness
• Impaired memory, attention concentration
• Personality changes
• Treatment
• No signature EEG pattern
• Determine affected cortical regions using QEEG
• 60 of patients improved after 40 biofeedback
  sessions

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Brain Stem Potentials

• Subcortical function measured using auditory
  stimuli
• 10 auditory clicks per second
• Independent of attention level (coma)
• Locate midbrain and brainstem tumors
• Wave I 8th cranial nerve activity
• Wave II 8th cranial nerve lower pons
• Wave III pons
• Waves IV V inferior colliculus
• Waves VI VII neurons from thalamus to
  auditory cortex

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Coma Brain Death

• Isoelectric or flatline EEG
• EEG lt 2µV in amplitude
• Indicates brain death after 2 exams in 24 hours
• Coma patients
• May show ERP responses to visual and
  somatosensory stimulation
• Some regain spontaneous cortical activity

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Multiple Sclerosis

• Degeneration of myelin covering on axons
• Abnormal visual ERPs
• P100 delayed, deviant waveform
• Abnormal brain stem potentials
• Abnormal somatosensory ERPs (delayed)
• Increased sensitivity for diagnosis
• ERP 90.5
• MRI 71.4

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CNS Degenerative Disease

• Spinal cord ERPs
• Conduction velocity delayed
• Cerebral ERPs may be absent
• Delayed visual ERPs
• Detect lesions on optic nerve
• Monitor compression of optic nerve by tumors
• Determine effects after surgery

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Huntingtons Chorea

• Inherited subcortical dementia (midbrain)
• Delayed sensory ERPs
• N1 and P2
• Delayed cognitive ERPs
• N2 and P300
• Visual ERPs
• Reduced amplitude in P100

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Parkinsons Disease

• Motor disorder
• Dopamine deficiency in basal ganglia
• Auditory ERPs
• Decreased amplitude of N1 and P3
• Prolonged N2 latency during sensorimotor task

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Alzheimers Disease

• Loss of cognitive functions (esp. memory)
• Auditory ERPs
• Prolonged P300 latency
• Decreased amplitude of P300
• Distributed differently among brain locations

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Human Immunodeficiency Virus

• Neurological complications may occur in 32-87 of
  patients
• Encephalitis
• Dementia
• Tumors
• Decreased P300 amplitude
• Delayed P2 and P300 responses

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EEG Biofeedback Epilepsy
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What is Epilepsy?

• brain disorder, aka seizure disorder
• 4 million epileptics in the U.S. (The Epilepsy
  Foundation)
• During epilepsy - neurons in the cerebral
  hemispheres misfire and create abnormal
  electrical activity.
• People with epilepsy have seizures that prevent
  the brain from
• interpreting and processing incoming sensory
  signals
• controlling muscles.
• Many types
• - petit mal epilepsy
• - grand mal epilepsy,
• - psychomotor epilepsy

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EEG in Epilepsy

• Epilepsy produces abnormal EEG patterns
• Epileptic activity take many forms generalized
  or focal
• Spike activity is often seen.
• In petit mal epilepsy waves of 3 per second
  spike are common
• Psychomotor epilepsy often show spike complexes
  that occur over the affected lobe.

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Normal EEG
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Generalized epilepsy EEG
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Benign focal epilepsy EEG
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Use of EEG

• Help identify the location, severity, and type of
  seizure disorder.
• Drawback interpretation of borderline records
  due to these types of records show up in about
  20 of the normal population (Simpson Magee,
  1973)
• Give positive or negative results

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EEG Biofeedback and Epilepsy Applications

• Treatment have focused on influencing EEG pattern
  through BFT.
• Use of EEG/BFT started with Sterman and
  colleagues (increase in 12- to 16- Hz EEG in
  cats)
• Reduction in seizure frequency when biofeedback
  was used to train the production of 12- to 14- Hz
  EEG from over the Rolandic(central) cortex
  (Sterman and colleagues, 1974).
• EEG/BFT with epileptics is time-consuming and
  costly, although benefits are great

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Brain-Computer Interface (BCI)

• Thought Translation Device
• Mu based BCI
• Implanted
• Case Study Matt Nagle

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Thought Translation Device

• Niels Birbaumer Tuebengin University
• Provides Locked in ALS patients with a basic
  communications capabilities
• Patients learn to control slow cortical
  potentials (SCPs), a wave type that a wave-type
  with among the lowest frequencies (0.1-0.5 Hz)
  that can be detected by an EEG.

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SCP

• Patients learn to produce SCP shifts in positive
  and negative directions.
• Positive reinforcement used in the learning
  process.
• EEG ? Computer ? Cursor Movement on a screen.
• Stages
• Goal
• Language Support Program
• Takes time!

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How it works
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EEG and fMRI
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Mu Based

• Same principles of SCP based, now using Mu
  readings.
• Can be used (after training) by those with
  paralysis to control an orthesis by using thought
  and imagination.

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Neuromotor Prosthetic Device

• Monkey Studies
• Dawn Taylor
• Johan Wessberg
• Matt Nagle

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Matt Nagle Robo-Sapien
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References

• Andreassi, J. L. (2000) Human Behavior
  Physiological Response (4th ed). Lawrence
  Erlbaum Associates Mahwah, New Jersey.
• Brain Tuning, http//www.brain-tuning.de/2ndlevel/
  applic/impla2_2_b.htm
• Donahue Lab, http//donoghue.neuro.brown.edu/
• Guardian, http//www.guardian.co.uk/life/feature/s
  tory/0,13026,1448140,00.html
• Nature, http//www.niu.edu/user/tj0dgw1/pdf/tetrap
  legia2006.pdfsearch22doi3A10.10382Fnature0497
  022
• Schwartz, M.S. Andrasik, F. (2003). Biofeedback
  A Practitioners Guide (3rd ed). Guilford
  Press New York, NY
• U. Tuebingen, http//www.uni-tuebingen.de/uni/tci/
  projekte/als.htm