Auditory and Vestibular Function in Parkinson's Disease

The aims of this study are to:

1. Evaluate peripheral and central auditory and vestibular function in group of adults with idiopathic PD.
2. Determine the relationship between the presence of significant auditory and vestibular dysfunctions to patients' demographic, clinical (motor and non-motor manifestations) and treatment variables

Parkinson's disease (PD) is a progressive neurodegenerative disease of central nervous system that mainly affects the motor system . The worldwide data showed a rising prevalence of PD with age. Meta-analysis showed a prevalence of 41/100,000 in 40-49 years old; 107/100,000 in 50-59 years; 173/100,000 in 55-64 years; 428/10,000 in 60-69 years; 425/10,000 in 65-74 years; 1087/10,000 in 70-79 years; and 1903/100,000 in \>80 years. Some differences in prevalence have been observed in different geographic location and in relation to sex . Patients with PD have multiple non-motor symptoms (NMSs) including fatigue, sensory symptoms, autonomic disturbance. sleep disorders, neuropsychiatric abnormalities etc . In the last decade and even in early stages of PD, studies reported hearing and/or vestibular dysfunctions in patients with PD with an estimated frequency of 25-50% . In the last decade and even in early stages of PD, studies reported vestibular dysfunctions in patients with PD with an estimated frequency of 14-25% compared to 5 -7.4% of the general population matched for age.

The pathophysiologic mechanisms of NMSs with PD are complex. Experimental as well as functional neuroimaging (e.g. SPECT and functional MRI) studies found that outputs from basal ganglia are directed to the inferior colliculus, medial geniculate nucleus, and temporal cortex. Motor or NMSs, occur due to loss not only of dopaminergic neurons in the substantia nigra but also in other dopaminergic and non-dopaminergic areas of the brain including serotoninergic, noradrenergic, and cholinergic systems. Lewy bodies and neurites consisting of α-synuclein, the main pathological features of PD, were observed in brain hemispheres as well as, spinal cord, brainstem nuclei and fiber tracts including vestibular nuclei and efferent neuronal system within the inner ear .

Diagnostic basic audiologic and vestibular evaluation and electrophysiological testing as brainstem auditory evoked potential (BAEP), videonystagmography (VNG) and cervical (cVEMP) and ocular (oVEMP) vestibular evoked myogenic potentials are easily available and applicable in many parts of the world as diagnostic tests to objectively evaluate peripheral and central auditory and vestibular dysfunctions for many disease including PD . This may provide early drug intervention and rehabilitation for patients and improve their qualities of life.

Eligibility Criteria:
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