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Geodesic Sensor Net Technical Manual

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Electrical Geodesics, Inc.
Geodesic Sensor Net Technical Manual
Geodesic
Sensor Net
Technical Manual
0297

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Summary of Contents for Geodesic Sensor Net

  • Page 1 Electrical Geodesics, Inc. Geodesic Sensor Net Technical Manual Geodesic Sensor Net Technical Manual 0297...
  • Page 3 Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 January 31, 2007...
  • Page 4 Electrical Geodesics makes no warranty or representation, either express or implied, with respect to this manual, its quality, accuracy, merchantability, or fitness for a particular purpose. In no event will Electrical Geodesics be liable for direct, indirect, special, incidental, or consequential damages resulting from any defect or inaccuracy in this manual, even if advised of the possibility of such damage.

  • Page 5: Table Of Contents

    Sizing . . . 36 Infant Nets . . . 37 Repair . . . 37 Recycling and Disposal of Nets . . . 38 For More HCGSN Information . . . 38 Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 6 Electrolyte . . . 51 Lightning . . . 51 Service and Maintenance chapter 5 Geodesic Sensor Net . . . 53 Cable and Connector Checks . . . 56 Component Recycling and Disposal . . . 56 Applying the GSN chapter 6 Planning .
  • Page 7 Accessories and Supplies chapter 12 Net Support Kit . . . 115 Replacement Parts and Supplies . . . 115 Items in the Net Support Kit . . . 116 Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 8 Net Sizing and Sensor Layouts Appendix C GSN Pinouts Terminology . . . 131 Abbreviations . . . 131 Pinout Schematics . . . 132 Pinout Tables . . . 133 Glossary Index viii Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 9 Sensor connected by wire to pin 35 Sensor cut-away view 35 The HCGSN comes in adult (left) and child (right) sizes 36 2-10 Outrider sensor 37 2-11 Elefix gel 37 Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 10 6-18 Check mastoid sensor positions (128-channel HCGSN) 72 6-19 Move each sensor side to side or in a circle to establish scalp contact 73 6-20 A properly applied Net 73 Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 11 In the empty pedestal, place the sponge upright 97 9-17 Push the sponge in firmly 98 9-18 Hydrate and again push the sponge in 98 9-19 A poorly seated sponge 99 Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 12 128-channel HCGSN v.1.0 125 256-channel HCGSN v.1.0 126 64-channel GSN 200 v.2.0 127 128-channel GSN 200 v.2.1 128 256-channel GSN 200 v.2.1 129 Appendix C GSN Pinouts Schematic view of GSN connectors 132 Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 13 Net Sizing and Sensor Layouts GSN 200 sizing chart HCGSN sizing chart Sensor layouts Appendix C GSN Pinouts Pinout tables Sensor to 32-, 64-, and 128-pin plug Sensor to 256-pin plug xiii Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 14 List of Tables Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 15: Preface

    EGI currently offers two versions of the Geodesic Sensor Net: the HydroCel GSN (HCGSN) and GSN 200. This manual discusses the two models together because they share many similarities. General information about their individual properties is provided in Chapter 2, "HCGSN,”...
  • Page 16 Preface The GSN is an integral part of a Geodesic EEG System (GES), which is a complete package for acquiring and working with EEG data. The other parts are the GES hardware and the Net Station or Neurotravel Win software.
  • Page 17 Each manual assumes you are familiar with the platform for the specific EEG acquisition software program described. For Net Station, the platform is a Macintosh computer; for Neurotravel Win, it is a Windows-based PC. xvii Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 18: About This Manual

    A number of appendixes are also included: • Appendix A, "Technical Support” • Appendix B, "Net Sizing and Sensor Layouts” • Appendix C, "GSN Pinouts” xviii Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 19: Troubleshooting, Support, And Repair

    • In this manual, the following are treated as synonyms: Geodesic Sensor Net 200 and GSN 200 ; HydroCel Geodesic Sensor Net, HCGSN, and HydroCel GSN . • The terms GSN , Net , and Geodesic Sensor Net are generic references to both the GSN 200 and the HCGSN.
  • Page 20 Preface Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 21: Chapter 1 Gsn Introduction

    GSN I NTRODUCTION CHAPTER GI’s Geodesic Sensor Net (GSN) is designed to acquire dense-array EEG data using a Geodesic EEG System (GES). This manual, the Geodesic Sensor Net Technical Manual , describes the components of the Geodesic Sensor Net, their integration, and use.

  • Page 22: Safety

    Intended Use The Geodesic Sensor Net is intended for use in clinical and research settings, by trained technicians, to measure and record the electrical activity of the brain. It is designed to be used on adults, children, and infants. Its intended use is strictly limited to EGI Geodesic EEG Systems, as stated in the applicable regulatory filings.

  • Page 23: Regulatory Compliance

    • Certification : This medical equipment is certified to EN 60601-1, CSA 22.2 No. 601.1, CSA 22.2 No. 601.2.26, UL 2601, and IEC 60601-2.26. The Geodesic EEG System, of which the GSN is a part, carries the U.S. FDA Pre-market 510k Clearance, Canadian Medical Device License (Homologation d’un instrument...

  • Page 24: Sensor Array Overview

    For accurate control of this tension, it must be applied in direct lines between the sensor pairs, and only along those lines. Each line is a geodesic , the shortest distance between two points on the surface of a sphere.

  • Page 25: Subject Wearing An Hcgsn

    A functional diagram is shown in Figure 1-4. Monitor GSN sensor array Mouse Data acquisition computer running Amplifier EEG acquisition software Keyboard Figure 1-4. Functional block diagram of a typical GES Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 26: Sensor Array And Neurotravel Amplifier

    Physically, the GSN connects to the amplifier either directly (in the GES 120 or 140) or via a Geodesic Sensor Net interface cable (GSNIC; in the GES 200, 250, or 300). (For more information about the GSNIC, see the GES Hardware Technical Manual .)
  • Page 27 Universal Serial Bus (USB) cable (or in the case of the Net Amps 300, the FireWire cable) that connects the amplifier and the data- acquisition computer. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 28 1: GSN Introduction Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 29: Chapter 2 Hcgsn

    HCGSN CHAPTER he HCGSN retains EGI’s patented geodesic tessellation of the head (Figure 2-1), which is the hallmark of the Geodesic Sensor Net design. The HCGSN also employs the non-abrasion high-impedance application method used with the GSN 200. Figure 2-1. 128-channel HCGSN, front (left) and side (right) views The HCGSN comes in two configurations:...
  • Page 30 GSN 200). In addition, HCGSNs with more than 32 channels feature a Y clip that is secured onto the subject’s collar to relieve the strain of the wires on the Net structure. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 31 Cord lock for chin strap Eye electrode band (small bead) Ear electrode band (big bead) Front Ear cut-out section Stabilizer pedestals Wire wraps Back Side Figure 2-3. HCGSN (128-channel model) Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 32: Tension Structure And Pedestal Design

    2: HCGSN Tension Structure and Pedestal Design The geodesic tessellation that is the basis of both the HCGSN and GSN 200 provides not only even intersensor distances across the head surface, but also uniform radial compression at each sensor pedestal. The tessellation ensures a rapid, evenly spaced, and comfortable Net application that requires no scalp abrasion.
  • Page 33 (produced by the friction between two objects). In addition, the coaxial shielding decreases the pickup of environmental electromagnetic noise. More information about the general electrode design is provided in “Features” on page 34. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 34: Features

    1-meter-long shielded wire to a Hypertronics-compatible, gold- plated pin (Figure 2-5). The electrode pellet features a wide, flat base. Electrode pellet Shielded lead wire Figure 2-5. Electrode Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 35: Pedestal And Electrode

    Cutting the pedestal assembly of the sensor down the middle makes its construction easier to see (Figure 2-8). Electrode pellet Lead wire Sponge Pedestal wall Figure 2-8. Sensor cut-away view Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 36: Sizing

    2: HCGSN Sensor Array The geodesic tension structure is die cut from a polyurethane sheet. The resulting polyurethane web features holes for the sensors, which are “snapped on.” An electrode pellet is first inserted into its corresponding hole; then, a pedestal is snapped on the other side of the hole, securing the sensor in place in the Net structure.

  • Page 37: Infant Nets

    EGI recommends checking for skin pressure points, overturned sensors, and redness under the chin strap every 15 minutes to maximize infant comfort. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 38: Repair

    Chapter 7, "Rinsing and Disinfecting.” • Sponge replacement instructions for the HCGSN are provided in Chapter 9, "Replacing GSN Parts.” • Sizing and sensor maps are in Appendix B, "Net Sizing and Sensor Layouts.” Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 39: Gsn 200

    Figure 3-2 shows the parts of the GSN 200. Note that each sensor is wired to an individual pin on the Hypertronics connector. Figure 3-3 shows front, side, and back Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 40: Gsn 200 (256-Channel Model)

    Cord lock for chin strap Cord lock for eye and ear electrode bands Front Side Back Figure 3-3. GSN 200 (128-channel model), without wire management Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 41: Tension Structure And Pedestal Design

    3: GSN 200 Tension Structure and Pedestal Design The sensors that make up the GSN 200 are sewn into a geodesic structure using durable polyurethane elastomer threads that form the tension lines of multiple icosahedra. As the GSN 200 is stretched over a subject’s head, the sensors make electrical contact with the scalp and are held firmly in place, normal to the head surface, by the...

  • Page 42: Pedestal Components

    By definition, a sensor (Figure 3-6) consists of a pedestal and an electrode. Sponge, pedestal, and Hypertronics pin electrode pellet Figure 3-6. Sensor Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 43 Hypertronics connector of the sensor array. Sensors are sewn into a geodesic tension structure of elastomer thread. The cap of the pedestal functions as a snap-in, hold-down device that fixes the sensor in position in the GSN 200.

  • Page 44: Sizing

    Figure 3-9 shows both sides of the special connector for the 64-channel infant GSN 200, with a shorting strap connecting the channel 63 and channel 64 outrider jacks to the isolated common jack. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 45: Infant Net Special Hypertronics Connector, With Outrider Jacks Strapped To Isolated Common

    EGI recommends checking for skin pressure points, overturned sensors, and redness under the chin strap every 15 minutes to maximize infant comfort. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 46: Repair

    (Figure 3-11). Figure 3-11. Avoid passing connector or sensor end of GSN 200 through lead bundle Recycling and Disposal of Nets See “Component Recycling and Disposal” on page 56. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 47: For More Gsn 200 Information

    • Electrode replacement instructions for the GSN 200 are provided in Chapter 9, "Replacing GSN Parts.” • Sizing and sensor maps are in Appendix B, "Net Sizing and Sensor Layouts.” Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 48 3: GSN 200 Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 49: Chapter 4 Safety

    CHAPTER his chapter provides an overview of safety cautions and warnings related to the Geodesic Sensor Net. The information in this chapter applies to both the GSN 200 and HCGSN models, unless otherwise noted. It is important to use the GSN only according to the manufacturer’s instructions and to use only EGI electrodes and parts.

  • Page 50: Skin Irritation

    GSN are kept separate. Do not use the same towel to dry the subject’s face or hair, and then to pat the Net dry. Also do not use the same towel for more than one subject. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 51: Cords, Connectors, And Cables

    However, because of the large, unpredictable electrical charges involved in a lightning strike, disconnect the subject and discontinue the data-acquisition session during a thunderstorm. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 52 4: Safety Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 53: Chapter 5 Service And Maintenance

    CHAPTER AINTENANCE his chapter summarizes some of the main service and maintenance issues related to the Geodesic Sensor Net. The information in this chapter applies to both the GSN 200 and HCGSN models, unless otherwise noted. Geodesic Sensor Net The GSN is shipped to you in a clean, disinfected condition. Attention to the maintenance instructions in this section will prolong the Net’s service life, ensure...
  • Page 54 • No rubbing alcohol. Isopropyl alcohol will cause the sponges to disintegrate. • Keep connector dry. Do not immerse or rinse the Net connector. • Do not autoclave any part of the Geodesic Sensor Net. Most epoxies and cable insulations will not withstand steam sterilization.
  • Page 55 Electrolyte Formulations The Geodesic Sensor Net uses mild electrolyte formulations for electrode application. These formulations include the HydroCel Saline (potassium chloride based) and the HydroCel HS (hydrogel). The HydroCel Saline and HS are in powder form and must be mixed with water.

  • Page 56: Cable And Connector Checks

    You may return components to EGI for recycling or disposal, if desired. Contact support@egi.com to arrange for this service. Please disinfect the Net (see page 81) before returning it to EGI. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 57: Chapter 6 Applying The Gsn

    6 PPLYING THE CHAPTER his chapter describes the Geodesic Sensor Net application process, which includes: • gathering needed supplies, • preparing the electrolyte formulation, • making head measurements, • applying the GSN to the subject’s head, and • removing it.

  • Page 58: Preparing The Electrolyte Formulation

    The HydroCel Saline comes in powder form and must be mixed with water before using. No subject cleanup is required. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 59 HS comes in powder form and must be mixed with water before using. No shampoo is required for cleanup. Use these solutions only on EGI Geodesic EEG Systems. The GSN 200 and the HCGSN with sponge inserts use only the HydroCel Saline; the HCGSN without sponge inserts uses only the HydroCel HS.

  • Page 60: Head Measurement

    6: Applying the GSN Head Measurement Before applying the Geodesic Sensor Net to the subject’s head, you must make several head measurements to: • calculate the proper Net size • determine the vertex point Net Size Before applying the GSN to the subject, measure the circumference of the subject’s head to determine the appropriate Net size, using Table B-1 on page 121 and Table B- 2 on page 122 as references.

  • Page 61: Skull Landmarks

    (intersection of the preauricular midpoint and the nasion–inion midpoint) Distance between Distance between the the nasion and preauricular points the inion Inion Preauricular point Nasion Gray’s Anatomy Preauricular point Figure 6-2. Skull landmarks Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 62: Net Application

    Caution!: Ask the subject to remove earrings, glasses, barrettes, and hair ties. Earrings can be especially uncomfortable with an HCGSN applied. Glasses can be replaced after Net application, as needed. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 63: Placing The Sensor End Of The Net In The Electrolyte Bucket

    For subjects with long hair, ask them to brush their hair back, so that it falls toward the back of the head, away from the face. Drape a towel over the subject’s shoulders. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 64: Lifting The Net Out Of The Electrolyte Bucket

    Proper positioning of the hands is important because it enables you to stretch the Geodesic Sensor Net over the subject’s head without unduly straining the tension structure and to remove your hands easily from the Net, once it is applied.

  • Page 65: The Hcgsn Features Red Pedestals For The Nasion And Cardinal Points

    6: Applying the GSN Figure 6-7; cardinal sensors are located at the vertices of the major triangles and used in EGI’s Geodesic Photogrammetry System). Figure 6-7. The HCGSN features red pedestals for the nasion and cardinal points ° Locate the back of the Net (this is where the wires exit the sensor array for the HCGSN).

  • Page 66: Place Thumbs Under The Net's Perimeter Band

    “dry” Net (one without electrolyte) on a colleague. Evenly spaced electrodes are important for data analysis such as grand averaging. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 67: Stretch The Perimeter Band With Thumbs And Little Fingers

    Slowly pull straight downward with your thumbs and little fingers, keeping the vertex electrode over the vertex and the nasion electrode aligned with the nasion. Standing directly in front of the subject makes this easier. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 68: Slowly Bring The Band Down Over The Head

    Check the positioning of the Net (Figure 6-11), and then disengage your hands. Note: A common mistake is to remove your hands before the back of the GSN is properly lowered over the head. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 69: The Hcgsn Features Cutouts For The Ears

    GSN 200, so make the face straps to adjust the chin strap, eye electrodes, and ear electrodes so that most sure: of the tension of the geodesic structure is directed downward. 1. The ears are not caught in the ear cut-out sections.

  • Page 70: The Nasion Is Too Far To The Subject's Left

    Next, adjust the orbital (ear and eye) sensors (Figure 6-16). Cord locks on either side of the subject’s cheeks independently adjust the lines retaining the infra- and extraorbital sensors, which slide along elastomer or polyurethane bands. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 71: Adjust The Orbital Straps (128-Channel Hcgsn)

    Check that a straight line of electrodes mark the center of the back of the head. Check lateral symmetry by confirming that the mastoid sensors fall at the same location behind each ear (Figure 6-17). Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 72: Adjust Big Sections Of The Net On Both Sides Of The Head

    (Figure 6-19). The brief (1–2 second) movement of each sensor is necessary to establish contact and, for most subjects, painless. However, some subjects have sensitive skin, so be attentive to any discomfort the subject may experience. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 73: Move Each Sensor Side To Side Or In A Circle To Establish Scalp Contact

    Follow a consistent order while working on sensor placement. Properly positioned sensors (Figure 6-20) should stand perpendicular to the scalp. Figure 6-20. A properly applied Net Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 74: Filling Pedestals With Hydrocel Hs

    Gently turn over the Reference sensor and fill the spongeless chamber with HydroCel HS. Carefully turn the pedestal upright on the head, making sure the sensor is resting on the scalp, not the hair. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 75: Removal

    Loosen the chin strap by pinching the cord lock under the chin and sliding it down the chin strap (Figure 6-22). Figure 6-22. Initial removal of the Net from the subject’s face Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 76: Peeling The Net From The Subject's Face

    The subject can now open his or her eyes. (If an HCGSN had been applied, the subject may exhibit some suction-like marks on exposed skin. These are not painful and generally disappear within 15 minutes.) Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 77 Follow the instructions in Chapter 7 to disinfect and rinse the Net, then hang it over the drying rack with the connector higher than the sensors. Do not package or transport damp Nets. Do not get the Hypertronics connector wet. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 78 6: Applying the GSN Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 79: Rinsing And Disinfecting

    Caution!: Proper care of your Net depends on following the instructions in this chapter. Failure to do so could result in degradation of your Geodesic Sensor Net. Rinsing The following instructions apply to all GSN models: GSN 200s, HCGSNs with sponge inserts, and HCGSNs without sponge inserts.
  • Page 80 Soak the afflicted Net in hot salt water (30 cc. or 2 tablespoons of KCl or NaCl. for each liter of water) for 30 minutes or more. Rinse as described in Steps 1–3 (above). Repeat soaking and rinsing procedure until the Net is clean. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 81: Disinfecting

    Net is soaking. Second Rinse Remove the Net from the disinfectant and repeat the warm water rinse (see page 79) three times to remove the disinfectant solution. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 82: Drying

    For tougher cases, you may need to apply a small amount of shampoo directly onto the affected sponges, rub gently with your finger, and follow the rinsing instructions on page 79. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 83: Chapter 8 Connectivities

    CHAPTER his chapter covers the receptacles, cables, and other connectors that are part of each Geodesic Sensor Net. Before connecting or disconnecting GSN components, please be sure you have read Chapter 4, "Safety.” Regularly check cables and connectors for wear or damage.

  • Page 84: Multicontact Hypertronics Receptacle

    Components Using the Hypertronics Connector The system connections that use the Hypertronics connector are shown in Figure 1-6 on page 26. The GSN and amplifiers connect to the Geodesic EEG System through the Hypertronics multipin receptacle and the Hypertronics multipin plug, respectively.

  • Page 85: Hypertronics Plug Released (Left) And Locked (Right)

    Inserting a connector with a bent pin can cause the pin to be completely bent over and in need of replacement. Released Locked Released Locked Figure 8-3. Hypertronics plug released (left) and locked (right) Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 86: Connecting The Net

    Twist the locking cam to secure the connector in place (see “Making and Breaking Figure 8-5. Plugging GSN into the Hypertronics Connections” on page 85). GSNIC and the articulated arm Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 87: Smart Nets

    Note: The 32-channel HCGSNs of the GES 120 and 140 do not use “Smart Net” technology. Geodesic Sensor Net Smart Net Coding 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19...

  • Page 88: Guide To Cabling

    Neurotravel amplifier. This connectivity scheme is shown diagrammatically in Figure 1-5 on page 26. In the GES 200, 250, and 300, the Geodesic Sensor Net interface cable connects the GSN to the Hypertronics connector on the front of the Net Amps 200 or 300 amplifier.

  • Page 89: Chapter 9 Replacing Gsn Parts

    Hypertronics contact. The kit (Figure 9-1) does not contain a pedestal because the replacement process uses the existing pedestal of the sensor that is receiving the new electrode. Figure 9-1. Electrode-replacement kit Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 90: Tools Needed For Replacing Electrodes

    • pin extraction tool (Hypertronics) • slot-head screwdriver Figure 9-2. Tools needed for replacing electrodes In addition, a roll of electrical tape and scissors for cutting the tape are needed. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 91: Remove The Handle On The Hypertronics Plug

    (Figure 9-5). Save the screws and the clamp in the bag with the other parts. Figure 9-5. Remove the screws and slide the clamp out Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 92: Let The Wires Hang Loose

    U se the pinout scheme in Letters Numbers Appendix C, "GSN Pinouts,” to locate the correct contact (Figure 9-8). Figure 9-8. Note the numbers and letters marked on the connector Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 93: Push The Tool Until The Contact Pin Slides Out

    Figure 9-10. Push the tool back into the module and begin until the contact pin slides out again by reinserting the tool over the contact until you hear the click. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 94: Use A Pair Of Needle-Nose Pliers To Grip The Contact And Pull It Out

    If you have to use too much force to pull the sponge into the housing, trim the sponge slightly for a secure but gentle fit. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 95: Enlarged View Of Hypertronics Contact

    Figure 9-13. View of connector before inserting contact Note: A condensed version of the replacement instructions are included on the back of the replacement electrode package label (Figure 9-1). Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 96: Replace The Hood Without Crimping The Wires

    (Figure 9-14). Replace the handle. Figure 9-14. Replace the hood without crimping the wires Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 97: Replacing Sponges (Hcgsn)

    Replace only sponges that have Position the sponge upright so that the fallen out of their pedestals electrode sits in the sponge’s center Figure 9-16. In the empty pedestal, place the sponge upright Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 98: Push The Sponge In Firmly

    Push the wet sponge firmly into the your thumb pedestal Figure 9-18. Hydrate and again push the sponge in Repeat Steps 4–5, until the sponge is firmly seated in the pedestal. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 99: Other Repairs

    In the event that a Net needs servicing or refurbishment, contact EGI Technical Support (Appendix A). Please disinfect the Net (see page 81) before returning it to EGI. Disposal of Electrodes or Sponges See “Component Recycling and Disposal” on page 56. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 100 9: Replacing GSN Parts Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 101: Net Faqs

    If you do not like the choice of reference, you can readily reference signals in the software, on the fly, or after the fact to any particular Geodesic Sensor Net sensor or group of sensors, including average reference.

  • Page 102: Application And Comfort

    Yes. In fact, numerous subjects have commented on the snug and comfortable fit of both the GSN 200 and the HCGSN. The geodesic tesselation covers the head evenly and firmly, thus uniformly distributing the tension of the structure and preventing painful pressure points from developing.
  • Page 103 • Y clip : Secure the Y clip to the subject’s collar to relieve some of the strain on the geodesic structure. (Exception: 32-channel model has no Y clip.) Geodesic Sensor Net Technical Manual...

  • Page 104: Electrolyte Formulations

    10: Net FAQs • Die-cut structure : The die-cut geodesic structure provides a closer head fit than the GSN 200. This snugger fit makes it even more important that the subject keep his or her eyes closed as instructed. The tighter web structure also makes it more challenging to achieve an evenly spaced application.

  • Page 105: Care And Maintenance

    • Do not leave the Net in disinfectant for more than 10 minutes. How long your Net lasts also depends on frequency of use. In general, a GSN has a life span of two years. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 106 10: Net FAQs Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 107: Chapter 11 Troubleshooting

    CHAPTER escribed in this chapter are a number of possible problems that may arise in connection with using Geodesic Sensor Nets. For each problem, one or more remedies are proposed. In cases where none of the remedies corrects the problem, do not use the GSN to collect EEG.

  • Page 108: Eeg Contains Excessive Noise

    Power cables carry relatively large-amplitude, 50- or 60-Hz electric and magnetic fields. These transmit noise to nearby cabling. • Check that there are no power cables near the subject or the interface cable connecting the GSN to the amplifier. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 109: Eeg Of Poor Quality

    • flatline or relatively low-amplitude waveforms at a single channel, a group of neighboring channels, a set of non-neighboring channels, or the entire sensor array • certain channels being steadily or intermittently stuck at maximum amplitude, also called railing Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 110 As the temperature stabilizes, so does temperature-induced drift. • Check that the electrolyte was properly prepared. Weak electrolyte degrades data quality. If uncertain, use fresh electrolyte. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 111 Hypertronics pin or to its associated electrode. For instructions on how to diagnose a faulty sensor and/or lead, see the next section, “Faulty Sensors.” Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 112: Faulty Sensors

    GSN sensor array but resides in the GSNIC, the amplifier, or elsewhere. If a different Net does not exhibit the same faulty sensors, then the problem likely is local to the Net with the faulty sensors. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 113: Before Replacing A Sensor

    Net any time the GSN 200 is not being applied to a subject. When applying the GSN 200 to a subject, slide the wire guide toward the connector end of the Net. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 114 Dried-on HydroCel HS may permanently damage the appearance and/or function of the HCGSN. This damage is not covered under warranty. For instructions on how to remove residual HydroCel HS from an HCGSN, see “Rinsing (HydroCel HS)” on page 80. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 115: Chapter 12 Accessories And Supplies

    CHAPTER UPPLIES very complete Geodesic EEG System ships with a Net Support Kit. Some of the items in the Net Support Kit are also available for separate purchase from EGI. In this chapter, we provide a reference list of all the items that are part of the Net Support Kit and indicate which are available for separate purchase.

  • Page 116: Items In The Net Support Kit

    *also sold separately Towels (1 pk of 6) Timer (1) N-PRT-TIM-1000-000 N-PRT-TOW-1000-000 Measuring Tape (1) Measuring Spoon Set (1) N-PRT-MET-1000-000 N-PRT-MES-1000-000 China Marker (1) 1/8-in. Slot-Head N-PRT-CHM-1000-000; Screwdriver (1) N-PRT-CHM-2000-000 N-PRT-SCR-1000-000 Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 117 *also sold separately *also sold separately Pin Extraction Tool Styrofoam Head (1) (Hypertronics) (1) N-ACC-STH-1000-000 N-ACC-CON-2000-003 *also sold separately Laminated GSN Laminated Rinsing/ Application Placard (1) Disinfecting Placard (1) N-PRT-LAM-1000-001 N-PRT-LAM-2000-001 Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 118 Laminated Sensor Map Placard (1) (128 v2.0) (1) N-PRT-LAM-3000-001 N-PRT-LAM-4000-002 Laminated Sensor Map Laminated Sensor Map (64 v2.0) (1) (256 v 1.0) (1) N-PRT-LAM-6000-002 N-PRT-LAM-6000-002 Laminated Control III Instructions (1) N-PRT-LAM-7000-001 Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 119: Technical Support

    • Try to isolate the problem. Is your problem well defined and repeatable? • Document the problem. Carefully record and organize the details gleaned from the above step and report the problem to EGI. Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 120 A: Technical Support Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 121: Gsn 200 Sizing Chart

    Adult Small 32, 64, 128, and 256 11 years–adult 55.5–58 cm. Adult Medium 32, 64, 128, and 256 11 years–adult 58.5 cm. and above Adult Large 32, 64, 128, and 256 Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 122: Hcgsn Sizing Chart

    Pediatric Small Pediatric 51–54 cm. Pediatric Large Pediatric Large 54–56 cm. Adult Small Adult Small Adult 56–58 cm. Adult Medium Adult Medium 58 cm. and above Adult Large Adult Large Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 123: Sensor Layouts

    128-channel HCGSN v.1.0 page 126 256-channel HCGSN v.1.0 page 127 64-channel GSN 200 v.2.0 page 128 128-channel GSN 200 v.2.1 page 129 256-channel GSN 200 v.2.1 Figure B-1. 32-channel HCGSN v.1.0 Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 124 B: Net Sizing and Sensor Layouts Figure B-2. 64-channel HCGSN v.1.0 Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 125 B: Net Sizing and Sensor Layouts Figure B-3. 128-channel HCGSN v.1.0 Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 126 B: Net Sizing and Sensor Layouts Figure B-4. 256-channel HCGSN v.1.0 Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 127 B: Net Sizing and Sensor Layouts Figure B-5. 64-channel GSN 200 v.2.0 Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 128 B: Net Sizing and Sensor Layouts Figure B-6. 128-channel GSN 200 v.2.1 Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 129 B: Net Sizing and Sensor Layouts Figure B-7. 256-channel GSN 200 v.2.1 Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 130 B: Net Sizing and Sensor Layouts Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 131: Gsn Pinouts

    • REF = reference • AMP = amplifier • GSN = Geodesic Sensor Net Note: The 32-channel HCGSN for the GES 120 and 140 contains no separate reference sensor because it is designed to interface with the Neurotravel amplifier. In this Net model, the average signal on channels 1 and 2 (also known as Fp1 and Fp2) form the reference.

  • Page 132: Pinout Schematics

    Figure C-1 provides a schematic view of the connectors in 32-, 64-, 128-, and 256- channel Geodesic Sensor Nets. Note that the large pin in the middle occupies much space, causing the pinout-numbering scheme to skip rows 8–12 in the 128-channel GSN and rows 16–20 in the 256-channel GSN.

  • Page 133: Pinout Tables

    128-channel Net. These sensors/pins are absent in the case of the 64-channel Net. For the 32-channel Net, sensors 33–128 and their corresponding pin numbers are absent. Sensors Sensors Sensors Sensors 1–10 11–20 21–30 31–40 Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 134 7 to 13 AMP2 because rows 8–12 ???? are occupied by the GSN0 pin (see Figure C-1). GSN1 Also, 32-channel GSN2 Nets do not contain GSN3 row 19. ???? Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 135: Sensor To 256-Pin Plug

    C: GSN Pinouts Table C-3. Sensor to 256-pin plug 256-channel GSN Sensors Sensors Sensors Sensors 1–10 11–20 21–30 31–40 Sensors Sensors Sensors Sensors 41–50 51–60 61–70 71–80 Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 136: Sensor

    Table D-3. Sensor to 256-pin plug Sensors Sensors Sensors Sensors 81–90 91–100 101–110 111–120 Sensors Sensors Sensors Sensors 121–130 131–140 141–150 151–160 Sensors Sensors Sensors Sensors 161–170 171–180 181–190 191–200 Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 137: Gsn

    AMP0 AMP1 AMP2 ???? Note: The pin- numbering scheme GSN0 jumps from 15 to 21 GSN1 because rows 16–20 GSN2 are occupied by the GSN3 pin (see Figure C-1). ???? Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 138 C: GSN Pinouts Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 139: Glossary

    flow of electrons through a conductor. Also know as electron flow. channel Each sensor of the Geodesic Sensor Net is cabled into the amplifier where its signal is converted into a stream of digital values. Each of these streams is the data of a channel.
  • Page 140 The shortest distance between electrolyte Electrically conducting two points on the surface of a sphere. liquid (wet) or paste (dry). The Geodesic Sensor Net is a structure Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 141 HydroCel Saline EGI’s classic zero of potential. potassium chloride saline electrolyte solution for 2-hour recordings with a GSN See Geodesic Sensor Net . GSN or an HCGSN with sponge inserts. GSNIC Geodesic Sensor Net interface cable. See interface cable .
  • Page 142 Glossary interface cable The cable connecting the Geodesic Sensor Net to the amplifier. The interface cable connectors are nasion The point where the bridge of Hypertronics connectors. This cable is the nose meets the skull. also known as the Geodesic Sensor Net interface cable (GSNIC ).
  • Page 143 The socket An opening or cavity into which Geodesic Sensor Net has a reference something fits. electrode located at the vertex. sterilization The process of killing all microbes in a material.
  • Page 144 The bridging bone from the cheekbone to the skull at the ear, with the jaw hinge and the big temporalis muscle below it. Also called the zygomatic arch . Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...

  • Page 145: Index

    NDEX role in an EGI Geodesic EEG System symbols/labels on equipment application differences between GSN 200 and two models of HCGSN Geodesic Sensor Net interface cable average life span of GSN geodesic tessellation glabella GSN 200 average life span care of GSNs...
  • Page 146 HydroCel CleanLeads HydroCel HS HydroCel Hydrating Skin Interface Chamber reference vs. common HydroCel Saline regulatory compliance of GSN Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 147 64-channel HCGSN sensor layout Smart Nets not detected subject cross-contamination tangles in GSN 200 32-channel HCGSN sensor layout 256-channel GSN 200 sensor layout 256-channel HCGSN sensor layout vertex vertex reference zygomatic bone Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 148 Index Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007...
  • Page 150 Electrical Geodesics, Inc. (EGI) 500 E 4th Avenue, Suite 200 Eugene, OR 97401 USA +1.541.687.7962 (tel) • +1.541.687.7963 (fax) www.egi.com...

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