CLTM: LTM EEG Instumentation actual exam questions and answers

Which of the following will see the greatest attenuation by a LF filter setting of 1 Hz? A. 10 Hz B. 5 Hz C. 0.5 Hz D. 0.1 Hz D. 0.1 Hz ACNS Guideline for LTM recommends a minimum storage capacity for how many hours of Video/EEG? 24 hours ACNS Guideline for LTM recommends a LFF setting of ___________. 0.5 Hz or less. ACNS Guideline for LTM recommends an EEG Amplifier noise level of ___________. Less than 1 microvolt rms. ACNS Guideline 12 ACNS Guideline for LTM recommends an INPUT impedance of at least _______________ for EEG amplifiers. 1 mega ohm. ACNS Guideline for LTM recommends a common mode rejection of EEG amplifiers of at least _________________. 60 dB ACNS Guideline for LTM recommends a dynamic range for EEG amplifiers of at least _________________. 40 dB What does the ACNS Guideline for LTM specify as the minimum number of channels recommended for pre-surgical work-up? 32-64 channels if pre-surgical work-up. What does the ACNS Guideline for LTM specify as the minimum number of channels recommended if NOT for pre-surgical work up? 16 channels if NOT pre-surgical work-up. Low pass filter setting for LTM recording should be: 70 Hz Minimum sampling rate for A-D conversion of LTM recordings should be _________________. 256 samples/second, selected to be more than three times the high frequency filter setting - assuming a 70 Hz HFF. Higher rates such as 512 Hz are preferable to prevent aliasing on modern high-resolution computer screens. Digitization should use a resolution of at least 16 bit/sample. Most modern clinical EEG amplifiers record with a bit depth of 24. A resolution of 16 or more bits is preferable. Describe aliasing When high frequency waveforms are falsely represented as lower frequency waveforms due to inadequate sampling rate. What are the technical specifications recommended by ACNS for filter settings on a LTM machine? LFF 0.5 Hz or lower HFF 70 Hz or higher According to the ACNS guidelines for LTM - What are the technical specs for electrical noise? Noise level less than 1 uV rms. Input impedance of at least 1 M ohm. Dynamic range of at least 40 dB. What are the technical specs for data acquisition/storage? Able to record at least 24 hours of video and 32-34 channels of EEG. Able to store a minimum of 30 GB or 24 hours video/EEG. What is the number of channels ACNS recommends as minimally sufficient for Ambulatory EEG? 8 Channels What is the current range for impedance measurements recommended by ACNS that can be safely performed for intracranial (epidural, subdural, intracerebral and foramen ovale) electrodes? 10 nA. This is 1000 times less voltage than the normal 10 K ohm impedance measurements of scalp electrodes. Care must be taken not to polarize intracerebral electrodes. Electrode conductivity and integrity of insulation should be checked prior to sterilization of the electodes.