Diagnostic Role of EEG in Parkinson’s Disease Patients with Cognitive Impairment

INTRODUCTION: The most common finding in comparative electroencephalography (EEG) exams in patients with Parkinson’s disease and healthy individuals in similar age groups is the increased generalized or localized slow-wave activity. The present study aims to investigate the EEG findings in patients with Parkinson’s disease and to determine their possible contribution to diagnosis.
METHODS: The study included patients followed up by the Movement Disorders Outpatient Clinic for diagnosed Parkinson’s disease. The Unified Parkinson’s Disease Rating Scale (UPDRS) was used to rate the clinical disability in patients with Parkinson’s disease with and without dementia based on DSM-V criteria. Patients were also evaluated using the Standardised Mini-Mental State Examination (SMME), the Geriatric Depression Scale (GDS), and the Neuropsychiatric Inventory (NPI). EEG recordings were performed according to the 10-20 system in both the patient group and healthy individuals in similar age groups with no metabolic/organic diseases.
RESULTS: 60 patients (16F, 44M, mean age: 69.23±11.56 years) diagnosed with Parkinson’s disease were compared with a control group of 25 individuals (17F, 8M, mean age: 70.12±8.18 years). In the patient group, 19 patients (31.7%) showed EEG pathology in the form of 4-8 Hz theta wave activity interpreted as mild disorganization, while 2 patients (3.33%) showed nonspecific slow-wave activity on both hemispheres. In the control group, only 1 patient (4%) had pathological EEG findings. 47.6% of the patients with Parkinson’s disease dementia showed EEG pathology. 2 patients with nonspecific slow-wave activity on both hemispheres were found to be from the Parkinson’s disease dementia group. Patients with EEG pathology had higher UPDRS scores (p=0.011), lower SMME scores (p=0.002), and higher NPI scores (p=0.004).
DISCUSSION AND CONCLUSION: The present study points out that there is a parallel between the development of dementia and EEG pathology in Parkinson’s disease and thus EEG may be important in the diagnosis and follow-up of cognitive decline.