CNIM - Practice Questions

What time constant would be the most effective for cutting out low frequency noise from your SSEP cortical responses? - ANSWER--Answer: 10 mS SSEP cortical responses are in the typical frequency range of 100-200 Hz. That being said, let's see what time constant would give us a good Low Frequency Filter. Remember LFF filters out everything below the cut off frequency and passes higher frequencies. Formula to know: Cut off Frequency = 1 / Time Constant (tc) 1/.01 s = 100 Hz 10 ms = .01 s This answer would filter out everything below 100 Hz so it would eliminate all the frequencies lower than 100 Hz and pass desired response and all higher frequencies. In order to achieve asynchronous stimulation you need to: - ANSWER--delay the second stimulator, so the stim goes "left, right, left, right" What is the active electrode for recording popliteal fossa sciatic nerve response after PTN stimulation at the ankle? - ANSWER--PF distal: appropriate montage for recording pop fossa response is Pf (distal) - Pf (proximal). The distal electrode is placed directly behind the knee in the leg crease, and the proximal electrode is placed 2-4 cm proximal. The response recorded is the N9 propagated afferent volley A negative electrical field is recorded by the negative input of the amplifier channel, while a refere