Skull Cap Requirements Presentation

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Skull Cap Requirements Presentation

• Group 5
• Engineering 4017 - Engineering Design

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Project Overview
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General Description

• What is EEG?
• Why is the information being collected?

FOR MORE INFO...

• Refer to the following webpage http//www.epub.org
  .br/cm/n03/tecnologia/eeg.htm

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Mission Statement

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

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Existing System

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

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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

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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

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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

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Signal Processing

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

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Experimental Repeatability

• Essential
• Ability to position system on subject on
  subsequent occasions so that electrodes are
  within 1mm2 of original position.

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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

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Sampling Specifications

• Essential
• Rate 1kHz
• Resolution better than .15?V
• Range 400mV

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Skull Impedance

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

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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).

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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.

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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.

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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.

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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.

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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.

FOR MORE INFO...

• Refer to the Groups Website - http//www.angelfir
  e.com/il/skullcap/