Which is wrong regarding somato sensory evoked potentials (SSEP)?

Somatosensory evoked potential (SEP or SSEP) is the electrical activity of the brain that results from the stimulation of touch. SEP tests measure that activity and are a useful, noninvasive means of assessing somatosensory system functioning. By combining SEP recordings at different levels of the somatosensory pathways, it is possible to assess the transmission of the afferent volley from the periphery up to the coex. SEP components include a series of positive and negative deflections that can be elicited by viually any sensory stimuli. For example, SEPs can be obtained in response to a brief mechanical impact on the fingeip or to air puffs. However, SEPs are most commonly elicited by bipolar transcutaneous electrical stimulation applied on the skin over the trajectory of peripheral nerves of the upper limb (e.g., the median nerve) or lower limb (e.g., the posterior tibial nerve), and then recorded from the scalp. In general, somatosensory stimuli evoke early coical components (N25, P60, N80), generated in the contralateral primary somatosensory coex (S1), related to the processing of the physical stimulus attributes. About 100 ms after stimulus application, additional coical regions are activated, such as the secondary somatosensory coex (S2), and the posterior parietal and frontal coices, marked by a parietal P100 and bilateral frontal N140. SEPs are routinely used in neurology today to confirm and localize sensory abnormalities, to identify silent lesions and to monitor changes during surgical procedures. It is done mostly under General Anaesthesia to monitor neural pathway.