Inclusion Criteria:  Aged 18 to 65 years ASA physical status I-III Who received craniotomy and intracranial mass excision  Exclusion Criteria:  Diagnosed diabetic neuropathy Using pacemaker Needing vasoactive agent during the observation Using ketamine Using agents such as beta-blockers, beta-agonists, sympatholytic agents, atropine, neostigmine that will affect the sympatho-vagal balance during the observation period The patients who could not provide sufficient cooperation for scoring were not included in the study.