MAPT and Anxiety: BAI: Beck Anxiety Inventory; BDI-II: Beck Depression Inventory Second Edition; FIQ: Fibromyalgia Impact Questionnaire; HD-tACS: high-definition transcranial alternating current stimulation; NRS: numerical rating scale; PPT: pressure pain threshold; PSQI: Pittsburgh Sleep Quality Index; Tau: Tau protein; Aβ-42: Beta-amyloid protein 42 amino acid.