eg presentation

Views:
 
Category: Entertainment
     
 

Presentation Description

No description available.

Comments

Presentation Transcript

PowerPoint Presentation:

BASIC EEG IMPLICATIONS IN PSYCHIATRY SHASHWAT SAXENA Junior Resident II

PowerPoint Presentation:

What is EEG : Electroencephalography is non-invasive method for investigation of electrical activity of brain. Used to measure cortical neuronal activity through detection of potential differences across scalp WHAT IS EEG

PowerPoint Presentation:

WHY TO STUDY EEG IN PSYCHIATRY: To rule out physical or neurological causes before making psychiatric diagnosis May help in differential diagnosis and treatment selection May help in predicting prognosis

PowerPoint Presentation:

OVERVIEW

PowerPoint Presentation:

How to record EEG Electrode Placement 10-20 percent system is used This system measures the distance between readily identifiable landmarks on the head and then puts electrodes at 10 percent or 20 percent of that distance in an anterior-posterior or transverse direction Electrodes are denoted by upper case letter denoting underlying brain region Even number for right hemisphere and odd number for left hemisphere. C- central,P - parietal,F - frontal,O -occipital and A-earlobes Figure indicating location relative to midline with higher numbers for more lateral placement

PowerPoint Presentation:

Advantages of 10-20 system: Nasopharyngeal and sphenoid electrodes can be used to improve readings from frontal, temporal regions. Sphenoidal electrode gives more positive results than regular electrodes but it is an invasive procedure Special electrodes

PowerPoint Presentation:

How to record EEG The way electrode pairs are arranged for recording is called a montage MONTAGE Bipolar TYPE OF MONTAGES Referential

PowerPoint Presentation:

How to record EEG Sensitivity: Frequency filter setting

PowerPoint Presentation:

SPECIAL ACTIVATIONS:

PowerPoint Presentation:

BRAIN WAVE

PowerPoint Presentation:

NORMAL EEG TRACING Highly rhythmic with a frequency range from 8 to 13 Hz Constitute the dominant brain wave frequency of the normal eyes-closed wake EEG. Alpha activity is also most prominent over the posterior cortex, particularly the parietal, posterior temporal, and occipital cortex Occipital region being best suited to show this activity.. Alpha activity is abolished by eye opening, and alpha activity also disappears with drowsiness and sleep. Alpha activity can be highly responsive to cognitive activity, such as focused attention or concentration. Example ,alpha can be blocked or attenuated by engaging in visual imagery, numeric calculation etc. ALPHA RHYTHM

PowerPoint Presentation:

NORMAL EEG TRACING BETA RHYTHM Frequencies that are faster than the upper 13 Hz limit They are common in normal adult waking EEGs Particularly seen over frontal-central regions. The voltage of beta activity is also almost always lower than that of activity in the other frequency bands described previous The beta activity can be divided into low and high beta frequencies such as gamma 1 (25 to 35 Hz), gamma 2 (35 to 50 Hz), and gamma 3 (50 to 100 Hz)

PowerPoint Presentation:

NORMAL EEG TRACING Waves with a frequency of 4.0 to 7.5 Hz It is a prominent feature of the drowsy and sleep tracing Although theta activity is limited in the waking EEG, A small amount of sporadic, arrhythmic, and isolated theta activity can be seen in many normal waking EEGs, particularly in frontal-temporal regions Excessive theta in wake, generalized or focal in nature, suggests a focal pathological process THETA RHYTHM

PowerPoint Presentation:

NORMAL EEG TRACING NORMAL EEG TRACING Delta activity (equal to or less than 3.5 Hz) is not present in the normal waking EEG Is a prominent feature of deeper stages of sleep. The presence of significant generalized or focal delta in the wake EEG is strongly indicative of a P athophysiological process DELTA RHYTHM Evidence has been provided that high frequency oscillations within the gamma band (>30Hz) reflect mechanisms of cortical integration GAMMA RHYTHM

PowerPoint Presentation:

NORMAL EEG TRACING

PowerPoint Presentation:

FACTORS AFFECTING EEG Preponderance of irregular medium- to high-voltage delta activity in the tracing of the infant EEG activity gradually increases in frequency and becomes more rhythmic with increasing age . Rhythmic activity in the upper theta–lower alpha range (7~to 8 Hz) can be seen in posterior areas by early childhood By mid-adolescence EEG has the appearance of an adult tracing. Changes with Age

PowerPoint Presentation:

FACTORS AFFECTING EEG Changes with sleep The rhythmic posterior alpha activity of the waking state subsides during drowsiness and is replaced by irregular low-voltage theta activity. As drowsiness deepens, slower frequencies emerge, and sporadic vertex sharp waves may appear at central electrode sites The progression into sleep is marked by the appearance of 14-hz sleep spindles (also called sigma waves) Which, in turn get replaced by high-voltage delta waves as deep sleep stages are reached.

PowerPoint Presentation:

Wakefulness Low-voltage, mixed frequency activity Alpha activity with eyes closed Eye movements and eye blinks High tonic activity and voluntary movements NREM I Low-voltage, mixed frequency activity Theta activity, vertex sharp waves Slow eye movements Tonic activity slightly decreased from wakefulness NREM II Low-voltage, mixed frequency background with sleep spindles and K complexes None Low tonic activity NREM III High-amplitude slow waves occupying 20 to 50 percent of epoch None Low tonic activity NREM IV High-amplitude slow waves occupy >50% of epoch None Low tonic activity REM Low-voltage, mixed frequency activity Saw-tooth waves, theta activity, and slow alpha activity REMs Tonic atonia with phasic twitches Electroencephalogram Electrooculogram Electromyogram

PowerPoint Presentation:

Artifacts are electric potentials of nonbrain origin that are in the frequency and voltage range of EEG signals and that are detected by scalp electrodes. Common artifacts include eye blinks, vertical or lateral eye movements, muscle potentials from jaw clenching, perspiration artifacts (galvanic skin response), and head movement. Automatic artifact rejection programs exist for some computerized research applications, but they have not strongly entered the clinical arena. FACTORS AFFECTING EEG Artifacts

PowerPoint Presentation:

FACTORS AFFECTING EEG Changes with Medications Benzodiazepines always generate significant amount of diffuse beta activity. The highest proportion of abnormal EEGs occurred with C lozapine followed by lithium Lithium is capable of causing abnormal generalized slowing, paroxysmal activity, or both, including a 10 percent incidence of toxic delirium The highest incidence of EEG abnormalities was associated with clozapine > olanzapine > risperidone , fluphenazine >haloperidol. There was no EEG abnormalities seen with quetiapine . Presence of diffuse slowing in patient on psychotropic who has unstable condition should prompt to look for toxicity

PowerPoint Presentation:

Abnormal pattern of EEG -Diffuse slow waves seen in metabolic, toxic infectious state. Decreased background activity suggests generalized disturbance, symmetrical diffuse decreased activity suggests projected disturbance from midline sub-cortical structure -Focal slowing: strongly suggestive of Space occupying lesions -Temporal slowing :nonspecific finding may suggest cortical dementia anoxia EEG slowing and slow waves:defined as waves slower than expected i.e., in theta and delta bands.should be recognized in waking State

PowerPoint Presentation:

EPILEPTIFORM ACTIVITY ABNORMAL PATTERN OF EEG Sharp waves: they are clearly outside the regular background activity. Being interrupted by sharp waves with mean duration between 70-200ms Spikes: They are bi-or triphasic with an asymmetric configuraion,seep increase and shallow decrease. Duration 20-70hz and interrupting background activity Generally they are followed by slow waves which are which is electrophysiological correlate of inhibitory process Typical generalized 3/sec spike and wave activity: combination of spikes and slow waves in a frequency of 3-4Hz,maximum over frontal region Polyspikes:series of spikes in alpha or beta frequency . seen in patients of secondary epilepsy

PowerPoint Presentation:

ABNORMAL PATTERN OF EEG EPILEPTIFORM ACTIVITY Generalized epiletiform activity is seen in generalized epilepsy Focal discharges are suggestive of partial seizures Irregular polyspike spike complex is suggestive of myoclonic seizures 3/sec spike and wave is suggestive of absence seizures Triphasic waves are suggestive of metabolic alterations

PowerPoint Presentation:

Different types of EEG

PowerPoint Presentation:

Quantitative EEG studies 1.Distinguishing between delirium or dementia and depression. 2. Distinguishing between schizophrenia and mood disorders. 3. Assessing cognitive, attentional , or developmental disorders. 4. Distinguishing between environmentally induced and endogenously mediated behavioral disorders. 5. Evaluating alcohol or substance abuse. 6. Evaluating postconcussion syndrome Video EEG Determining whether seizures with unusual features are actually epilepsy, Identifying the type of seizures, and pinpointing the region of the brain where seizures begin. Locating the region precisely is essential if epilepsy surgery is being considered

PowerPoint Presentation:

EEG IN PSYCHIATRIC DISORDERS Currently there is no accepted indication of EEG in diagnosing either axis-I or II disorders

PowerPoint Presentation:

: EEG abnormalities have overall frequency of 20-60%. May predict conversion of subjects at risk into psychosis T heir presence indicate worse outcome. It helps to identify those with comorbid epileptic condition. E pileptiform variants are found in affective disorder with psychotic feature and schizoaffective disorder but not in schizophrenia. EEG abnormalities in schizophrenia : Dysrhythmia Spike and spike –and- wave Generalized slowing EEG IN SCHIZOPHRENIA EEG can help to find out specific etiology of catatonia as catatonia may be caused by several organic disorders EEG in Catatonia Reduced gamma in patients of nondeficit schizophrenia than deficit schizophrenia Increased delta activity in anterior cortical region in schizophrenia(QEEG) Catatonia with functional etiology would have normal EEG

PowerPoint Presentation:

EEG IN MOOD DISORDERS: Abnormal EEG found in 20-40% of patients In bipolar patients increase in beta activity and decrease in alpha activity noted Acute mania has increased posterior slow rhythms An asymmetric alpha activity in left frontal region has been reported in depression Unipolar and bipolar depression have sleeping EEG recording abnormality i.e., short REM latency, increased REM density and reduction in stage 3 and 4 of sleep. Frequent increase sharp spikes,6/sec spike in patients with suicidal ideation Q-EEG can predict positive or negative outcome of treatment with anti-depressants

PowerPoint Presentation:

EEG in OCD: 25-30% of panic attack patients have EEG abnormalities Helps in differentiating panic attack from epilepsy focal paroxysms of sharp wave activity coinciding with spontaneous onset of panic attack is noted EEG in OCD EEG in Panic disorders

PowerPoint Presentation:

Increased slow activity and decreased mean frequency are correlated with cognitive impairment and measures clinical severity of Alzheimer's dementia The amount of theta activity shows the best correlation with cognitive deterioration Increased delta appears to be correlate of severe advanced dementia, occurring subsequent to increased theta Alzheimer's dementia and frontopolar have been differentiated by evaluating asymmetry of slow activity EEG in DEMENTIA Helpful in differentiating dementia from pseudodementia

PowerPoint Presentation:

Hallmark of delirium usually is the slowing of the background EEG rhythm This is positively correlated with the degree of severity of the condition Exception is in delirium tremens (DT), which usually shows a normal EEG record with fast rhythms. D elirium accompanying the neuroleptic malignant syndrome shows only a mild diffuse slow wave. Delirium can be differentiated from dementia, and the significant factors are an increased theta activity EEG in DELIRIUM

PowerPoint Presentation:

Varying prevalence of EEG abnormalities in clinical population of violence, aggressive acts ranging from 6.6 %( rage attacks) to 53%(antisocial personality disorder) More aggressive the patient more abnormal is EEG Higher incidence of EEG abnormalities in criminals whose serious crimes were apparently motiveless or had minimal motives Majority of abnormality lie in temporal lobe consisting of diffuse baseline slowing and /or paroxysmal activity with/without spike Violence has been found to be significantly related to hemispheric asymmetry in EEG for frontotemporal region EEG in anti-social personality

PowerPoint Presentation:

EEG in EPILEPSY The EEG finding for a seizure disorder is the generalized, hemispheric, or focal spike or spike-wave discharge, or both. If petit mal status suspected, then the status can be confirmed quickly by an EEG demonstration of continuous, diffuse spike-wave activity.

PowerPoint Presentation:

EEG in EPILEPSY Irregular Polyspike spike complex is suggestive of myoclonic seizures

PowerPoint Presentation:

EEG in EPILEPSY EEG MONITORING Important role in the assessment of patients who present diagnostic or management difficulties following clinical evaluation and routine EEG Clinical Applications of EEG monitoring are: Diagnosis of paroxysmal neurological attacks Differentiation between nocturnal epilepsy and parasomnias Diagnosis of psychogenic non-epileptic seizures Characterisation of seizure type Quantification of IED or seizure frequency Evaluation of candidates for epilepsy surgery

PowerPoint Presentation:

Acute Alcoholic intoxication shows slowing in the EEG, seen as decreased alpha frequency and abundance & increased amount of theta, and even some generalized delta rhythm These slow waves have a relationship with the degree of intoxication. The extent of the disturbance of consciousness is related to the amount of slow activity Reports have appeared of an increased beta (relative power) in alcohol dependence Increased alpha power, especially in anterior regions, has been reported in withdrawal, as well as after acute exposure to cannabis EEG in Alcohol and Substance Abuse

PowerPoint Presentation:

Nonspecificity of findings Problem with placing electrodes in psychiatric patients Limitations of scalp EEG i.e.,Only one-third of brain can be covered,EEG activity of sub-cortical area can’t be recorded Currently there is no accepted indication of EEG in diagnosing either axis-I or II disorders LIMITATIONS WITH EEG IN PSYCHIATRY Because of these limitations of scalp EEG it can never give positive proof of absence of brain dysfunction

PowerPoint Presentation:

Polysomnography is a comprehensive recording of the biophysiological changes that occur during sleep. It is usually performed at night The PSG monitors many body functions including brain EEG , eye s movements (EOG), muscle activity or skeletal muscles activation (EMG) and heart rhythm (ECG) during sleep. Other investigations added are respiratory airflow and effort indicators along with pulse oximetry POLYSOMNOGRAPHY

PowerPoint Presentation:

POLYSOMNOGRAPHY

PowerPoint Presentation:

Use of Polysomnography

PowerPoint Presentation:

These are series of surface recordable brain waves that are time locked to the presentation of discrete stimulus. They are of small magnitude compared to ongoing EEG Signal reflecting response to stimuli is retained while background EEG activity is cancelled out Recognized on the basis of latency and polarity Helps in diagnosing psychiatric disorders,lie detection and psychogenic amnesia EVOKED POTENTIAL P300 is most studied evoked potential wave It appears as 3 rd positive peak and has latency of 300ms Evoked potential(P300) has been shown to be attenuated in Schizophrenia,ADHD,conduct disorder and substance use disorder

REFERENCES :

REFERENCES 1) Saddock B and Saddock V:Comprehensive Textbook Of Psychiatry,9 th edition 2)Nash B,Galderisi S,Pogarell O and Riggio S:Standard Electroencephalography In Clinical Psychiatry, A Practical Handbook 3)Hughes J and John E:conventional and quantitative electroencephalography in psychiatry. The Journal of Neuropsychiatry and Clinical Neurosciences 1999 4)S J M Smith; EEG in the diagnosis, classification, and management of patients with epilepsy J Neurol Neurosurg Psychiatry 2005;76:ii2-ii7 doi:10.1136/jnnp.2005.069245

authorStream Live Help