EPs are recordings of the nervous system’s electrical response to the stimulation of specific sensory pathways (., visual, auditory, general sensory). In tests of evoked potentials, a person’s recorded responses are displayed on an oscilloscope and analyzed on a computer that allows comparison with normal response times. Demyelination results in a slowing of response time. EPs can demonstrate lesions along specific nerve pathways whether or not the lesions are producing symptoms, thus making this test useful in confirming the diagnosis of MS. Visual evoked potentials are considered the most useful in MS.
Microbial catabolism of phytosterol side chains yields C-19 steroids, C-22 steroids, and 17-ketosteroids (. precursors to adrenocortical hormones and contraceptives ).     The addition and modification of functional groups is key when producing the wide variety of medications available within this chemical classification. These modifications are performed using conventional organic synthesis and/or biotransformation techniques.