1. Skull Cap Requirements Presentation Group 5 Engineering 4017 - Engineering Design

2. Project Overview

3. General Description What is EEG? Why is the information being collected? Refer to the following webpage http://www.epub.org.br/cm/n03/tecnologia/eeg.htm FOR MORE INFO...

4. Mission Statement The reliable measurement over extended periods of scalp EEG on consecutive occasions during mental function in everyday environments.

5. Existing System Skull cap containing electrodes with wired connection. Requires extensive preparation of scalp for usage. System must be operated in a shielded environment.

6. Issues with Existing System Lack of repeatability Lack of mobility Long setup time Short length of experiment before the results are affected by external factors

7. Requirement Structure Priority System –Essential - Match existing functionality and/or core customer requirements –Highly Desirable - Extend the functionality of the system and are achievable in the available time frame –Desirable - May not be achievable in the available time frame & further research is required

8. Electrode Positioning Essential Position 23 electrodes on the skull according to the 10/20 positioning convention –19 scalp electrodes –Two eye electrodes –Reference electrode –Isolated common

9. Signal Processing Essential Process electrode signals to make them suitable for input into customers existing computer system.

10. Experimental Repeatability Essential Ability to position system on subject on subsequent occasions so that electrodes are within 1mm 2 of original position.

11. Acceptable Noise Level Essential Noise from external electromagnetic fields and undesired physiological rhythms must be less than 1% of the recorded EEG signal. –E.g. power line hum, heart beats

12. Sampling Specifications Essential Rate: 1kHz Resolution: better than.15V Range: ±400mV

13. Skull Impedance Essential Skull impedance must be reduced below 5k for the purposes of electrode measurement.

14. Scalp Irritation Essential Based on ISO 10993-10, irritation should be reduced to a level such that less than 2% of subjects experience irritation (as defined in the standard).

15. Highly Desirable Less than 1% deviation of data due to electrode polarisation. Easily cleanable to medical grade cleanliness in accordance with Australian Standard AS 4187/1998. Signal compensation for up to 0.05Hz of signal drift.

16. Highly Desirable, cont. Suitable for use on persons of different head dimensions, within the range of 53 to 60 centimetres head diameter as measured above the ears. Possible to position system on subject's head within 15 minutes.

17. Desirable Exist as a portable system that can operate for up to three hours without interruption. Ability to transfer signals from the patient to a monitoring terminal without the need for physical connection. Ability to select a subset of the EEG monitoring electrodes.

18. Desirable, cont. Ability to select different sampling rates for data collection. Suitable for use on wider range of adult head dimensions and extending to smaller sizes for children.

19. Conclusion Requirements may be changed after consultation with the client From these requirements, conceptual designs will be generated and evaluated, with the successful design being further refined into a final product design. Refer to the Groups Website - http://www.angelfire.com/il/skullcap/ FOR MORE INFO...