Question Title: A different SSEP question

I have been told that it is not uncommon for the SSEP not to pick up the
PF and the P17, and that should not be of concern if it is absent. If you can not pick
up on it, how can you detect if it is abnormal or not? This concerns me
as there is latency in the P37, but unable to distinguish further locations
due to insufficient data. Any information that you may have to offer is
much appreciated.

Thank you

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The SSEP consists of a series of waves which are detected at various anatomical locations derived from a single type of stimulus.
Sometimes due to local anatomical factors or interference from local muscle electrical signals the SSEP signal may not be detectable at some points.
In this case obviously we cannot make any comment on the signal from that particular area, we can however comment on the signals whch are picked up further downstream.
If there is a delay or latency in any one of the waveforms then obviously the problem occurred prior to the point at which the delay is picked up, this delay will also be seen in the subsequent waves downstream.
If the last wave (the P37) isdelayed , the problem occured somewhere in the pathway from the peripheral nerve to the cerebral cortex, we can make this comment independently of the recording of any other waves en route.
Recording waves in between helps us to localize problems along the pathway but if absent do not prevent evaluation of the final waveform.

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