Inclusion Criteria:  Adults with age range 55-65 years old from both gender. Patients have to fulfil the criteria for diagnosis of idiopathic PD [Postuma et al., 2015]. and age, sex and socioeconomic matched healthy subjects recruited from the general population as controls for statistical comparisons.  Exclusion Criteria:  - Concomitant medical and metabolic illnesses. Secondary or atypical parkinsonism Evidence of concomitant cerebrovascular stroke temporally related to the onset of the disease. Major psychiatric disorder known to affect cognition. Dementia (i.e. mini mental score examination or MMSE score <24) Major language disturbance MRI brain showing structural lesion Severe known auditory (hearing thresholds >50 dBnHL) or visual impairment affecting their ability to complete testing before participation of the study. Improper neck movements that interfere with assessment. Middle ear diseases, ear infection, ear trauma, or acoustic trauma