1. A method comprising: applying a first type of external sensory stimulation to a patient; obtaining a baseline measurement of patient sensory response to the first type of external sensory stimulation; applying a second type of external sensory stimulation to a patient; obtaining a baseline measurement of patient sensory response to the second type of external sensory stimulation; applying neuromodulation therapy to the patient simultaneously with application of the first type of external sensory stimulation; obtaining a test measurement of patient sensory response to the first type of external sensory stimulation during simultaneous application of the first type of external sensory stimulation and the neuromodulation therapy; applying neuromodulation therapy to the patient simultaneously with application of the second type of external sensory stimulation; obtaining a test measurement of patient sensory response to the second type of external sensory stimulation during simultaneous application of the second type of external sensory stimulation and the neuromodulation therapy; evaluating efficacy of the neuromodulation therapy based on a comparison of the baseline measurements and the test measurements.