EEG (ELECTROENCEPALOGRAM)

This slide has been prepared in detaied manner and will help you.
The topics covered are:-
1- introduction
2.circuit diagram and its explaination
3.working
4. features
5.advantages / disadvantages
6. the top vendors

1. EEG (Electroencephalogram) BY:- SHRIYA GAUTAM

2. TOPICS COVERED 1 2 3 4 5 INTRODUCTION BLOCK DIAGRAM AND ITS EXPLAINATION APPLICATION VENDORS OF THE MACHINE ALONG WITH ITS COST ADVANTAGES / DISADVANTAGES

3. INTRODUCTION

4. Electroencephalogram An EEG machine is a device that records the electrical activity of the brain. It contain electrodes that can detect brain activity when placed on a subject’s scalp. The electrodes record the brain wave patterns and the EEG machine sends the data to a computer or cloud server.

5. BLOCK DIAGRAM

6. ELECTRODES Electrodes are used to record EEG signals. They are made of a conducting material commonly metals with some underlying conductive paste or gel to improve contact with the skin. An ideal electrode should transduce the voltage underneath it without altering it in any way. However, real electrodes have limits on their performance, including the frequency range over which they are accurate and the buildup of charge on the electrode. Gold or gold-plated electrodes have commonly been used for scalp EEG Recording .

7.  (A) International 10-20 system for electrode placement. (B) 10-10 or 10% system for electrode placement. Electrodes in black have different names from the corresponding electrodes of the International 10-20 system (T7 = T3; T8 = T4; P7 = T5; P8 = T6).

8. JACKBOX Jackbox  is the electrode board where each individual pin of the electrodes is plugged to pre-amplify and convert the analogue signal to one that is digital.

9. ELECTRODE MONOTAGE SELECTOR Montage  means the placement of the electrodes. The  EEG  can be monitored with either a bipolar  montage  or a referential one. Bipolar means that you have two electrodes per one channel, so you have a reference electrode for each channel.

10. EEG AMPLIFIERS 5. The amplification factor is referred to as gain and may be expressed as V out / V in 1. Electrical signals produced by the brain are in the order of microvolts. 4. An amplifier multiplies an input voltage By a constant usually lying in the range of up to 1,000,000. 2. They have to be magnified so that the voltage changes can be given sufficient power to be graphically displayed either on paper or on a computer screen 3. When measured directly at the cortical surface, these voltages are on the order of 10 mV. 

11. FILTERS The fact that the potential differences fluctuate as a function of time implies that the recorded signals have a certain bandwidth. For the majority of EEG investigations the recorded signal lies between 1 Hz and 70 Hz. Information will be lost if the frequency response of the recording channel is narrower than the frequency range of the EEG signal. If the frequency range of the recording channel is wider than the bandwidth of the EEG signal, noise in the recorded data will contain additional irrelevant information. EEG recording channels are equipped with adjustable high pass and low pass filters by which the frequency response can be restricted to the frequency band of interest. For standard recordings, the low frequency filter should not be higher than 1 Hz with the corresponding time constant of 0.16 s

12. USES OF FILTERS Low- pass filter  to  filter  out frequencies above 40 or 50 Hz. For standard recordings, the low frequency filter should not be higher than 1 Hz with the corresponding time constant of 0.16 s   EEG  signal processing is to apply a  high - pass filter  to  filter  out slow frequencies less than 0.1 Hz or often even 1 Hz.Distortion of higher frequency components is also possible when the high frequency filter is set lower than 70 Hz.   a  notch filter  is used to reject the 60 Hz or 50 Hz power line noise. The  notch  is a very selective  filter  with a very high rejection just for a tiny frequency band around the selected frequency. HIGH PASS FILTER NOTCH FILTER LOW PASS FILTER

13. WRITE OUT The final link between the patient and a legible EEG tracing is the writer. In conventional EEG machines, a pen-ink-paper system is employed The speed of the paper mechanism should include 30 mm/s with at least the additional speeds of 15 mm and 60 mm/s selectable during operation. The writing points of the different channels should be aligned on a line perpendicular to the direction of paper travel without the use of special tools and without the need for bending the writer arms.

14. A sample EEG recording showing a focal spike typical of a seizure

15. OUTPUT The number of channels that an  EEG machine   has is related to the number of electrodes used. The more channels, the more detailed the brainwave picture.This means that the  output  from the  machine  is actually the difference in electrical activity picked up by the two electrodes

16. Abnormal results from an electroencephalogram can indicate:   Migraines Bleeding (haemorrhage) Head injury Tissue damage Seizures Swelling ( edema ) Substance abuse Sleep disorders Tumours

17. APPLICATIONS Insert the title of your subtitle Here

18. Applications of EEG: EEG is mainly used in studying the properties of cerebral and neural networks in neurosciences. 2. It is used to monitor the neurodevelopment and sleep patterns of infants in ICU and enable the physician to use this information to enhance daily medical care. 3. In epilepsy, EEG is used to map brain areas and to receive localization information prior to a surgery.  4. The EEG neuro -feedback or EEG bio-feedback or EEG bio-feedback has many applications such as treating for physiological disorders and neurological disorders such as epilepsy. 5. Many disorders as chronic anxiety, depression etc can be found out using as EEG pattern.

19. ADVANTAGES

20. Advantages of EEG: 1.They are functionally fast, relatively cheap and safe way of checking the functioning of different areas of brain. 2. High precision time measurements 3.Today's EEG technology can accurately detect brain activity at a resolution of a single millisecond.  4.EEG electrodes are simply stuck onto the scalp. It is therefore a non-invasive procedure. 5 . EEG is simple to operate. 

21. DISADVANTAGES

22. Disadvantages of EEG: 1.The main disadvantage of EEG recording is poor spatial resolution. 2.The EEG signal is not useful for pin-pointing the exact source of activity. In other words they are not very exact. 3.EEG waveform does not researchers to distinguish between activities originating in different but closely adjacent locations.

23. FEATURES

24. Features of EEG: • Hardware costs are lower when compared with other imaging techniques such as MRI scanning. • EEG sensors can be deployed into a wide variety of environments. • EEG allows higher temporal resolution on the order of milliseconds. • EEG is relatively tolerable to subject movements as compared to MRI. • The silent nature of EEG allows for better study of the responses . • In EEG some voltage components can be detected even when the subject is not responding to stimuli.

25. TOP VENDORS

26. TOP 4 VENDORS OF EEG $25,000 $20,000 $22,000 $24,000

27. References https://www.electronicsandcommunications.com/2018/08/advantages-disadvantages-applications-of-eeg.html https://www.verywellhealth.com/what-is-an-eeg-test-and-what-is-it-used-for-3014879 https://mayfieldclinic.com/pe-eeg.htm https://neupsykey.com/eeg-instrumentation/ https://www.bitbrain.com/blog/eeg-amplifier https://www.medlink.com/article/technical_aspects_of_eeg