Quantification of Beta Activity in Routine EEG Recordings in Parkinson's Disease Patients
Condition: Parkinson Disease
MeSH terms: Parkinson Disease
Study type: Observational

Summary: 
      The investigators are studying the relationship between a certain oscillatory brain rhythm
      (13-30 cycles/sec) that emerges prominently in patients with Parkinson's disease and symptoms
      of slowness of movement. The investigators are recruiting patients with a range of severity
      of Parkinson's disease symptoms to perform electroencephalography (EEG), in which the study
      team records brain waves using electrodes placed on the scalp, while patients sit at rest or
      perform certain hand tasks. The investigators will analyze the recorded brain waves to
      extract the brain rhythm of interest and relate it to motor symptom severity as well as study
      its behavior during rest and hand movement.
    

Detailed description: 
      Parkinson's disease (PD) is a devastating, progressive neurodegenerative disease. The
      hallmark of PD is loss of dopaminergic neurons in the substantia nigra pars compacta (SNc),
      which disrupts motor circuit processing in the basal ganglia and results in motor dysfunction
      including tremor, rigidity, and bradykinesia. This disruption of motor circuit processing is
      reflected in abnormal oscillatory neural activity. For example, recordings of local field
      potentials with electrodes implanted in the basal ganglia reveal a substantial elevation of
      beta frequency (15-35 Hz) oscillatory activity in persons with PD, and this increased beta
      frequency activity is suppressed following levodopa treatment and deep brain stimulation.

      However, the link between the frequency and amplitude of abnormal oscillations and the degree
      of Parkinsonian symptoms is unclear. For example, magneto-encephalography revealed that
      beta-frequency oscillatory activity is elevated over the motor cortices even in persons with
      early-stage PD, and there were not any clear differences in beta frequency oscillations
      between newly diagnosed and under treatment PD. However, this study did not address any
      changes in the frequency of oscillations or distribution of power across frequencies. For
      example, a recent study has suggested that variability of ongoing beta-frequency oscillatory
      activity, in this case recorded from the STN, may be more strongly correlated with symptoms
      than the amplitude of beta frequency oscillations. Therefore, the objective of the
      investigator's proposed study is to determine whether there are changes in the
      characteristics of beta frequency oscillatory activity in the EEG over the motor cortex
      across differing degrees of Parkinson's disease. Such information is critical to
      understanding the (possible) link between abnormal oscillatory brain activity and symptom
      severity, as these signals could be used as potential biomarkers of therapeutic efficacy and
      to inform the design of new methods of intervention

      This is an observational, prospective evaluation of the beta content in routine 20-40 minute
      EEG recordings from patients with PD for varied periods of time. The investigators anticipate
      running data collection for 4-6 months in an outpatient movement disorders clinic. Subjects
      will be identified by their physician and then referred to the study team. Patients that
      agree to participate will be screened and have all questions answered at the time of their
      routine appointment. If the patient decides to participate and informed consent is obtained,
      a clinic appointment will be made for study data collection at a later date. Patient will be
      instructed not to take their normal dopamine replacement medications for 12 hours prior to
      the EEG study visit as this can interfere with the brain wave activity being studied. At the
      study clinic encounter, routine recordings will be made from a total of 33 PD patients; 11
      with <3 years of PD diagnosis, 11 with >5 but <10 years of PD diagnosis, and 11 with advanced
      >10 years of PD diagnosis. EEG will be recorded using an FDA template system to facilitate
      EEG lead placement by research coordinators. Clinical description of PD severity and duration
      will be collected from each subject through questionnaire and from review of clinical
      evaluation. A UPDRS score may be determined for each participant. Following the data
      collection period, the EEG recordings will be indexed, de-identified, and randomly ordered to
      blind the subsequent analyses. These indexed EEG segments will be quantitatively analyzed to
      determine the relative contribution of beta frequency to the recordings, and comparison
      between the duration and severity of PD symptoms and beta content will also be made.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Patients with a clinical diagnosis of PD will be recruited from Duke outpatient movement
        disorders clinics. Patients will be adults, age 18 or older who have had PD diagnosis for
        the following periods of time: Cohort A have had PD diagnosis for <3 years, Cohort B have
        had PD diagnosis for between 5 and 10 years, and Cohort C have had PD diagnosis for >10
        years. All demographic groups were offered participation in the study.
      
Keywords: EEG; Parkinson Disease; Beta Oscillations