Various embodiments concern identifying a biomarker in the presence of electrical stimulation. Various embodiments concern delivering electrical stimulation to a patient and sensing one or more signals while the electrical stimulation is being delivered, the one or more signals including data indicative of physiological activity. Various embodiments further include determining an intensity of the electrical stimulation and determining whether the data indicates the presence of a biomarker based on a variable threshold, the variable threshold being variable based on the intensity of the electrical stimulation. Various embodiments concern determining a relationship between stimulation intensity and a biomarker parameter to determine the variability of the variable threshold.