High Frequency Oscillations in Neurologic Disease

This study is designed to evaluate the high-frequency range deep brain oscillations (HFO) as
pathologic markers in patients undergoing deep brain stimulation for epilepsy or Parkinson
disease. Newly developed technology allows for the chronic recording of these brain signals
at the same time as clinical stimulation is occuring. We will learn both whether these HFO
correlate with disease activity and whether the HFO change in response to ongoing stimulation
(potentially giving insight into the underlying mechanism of action of DBS). Study
participants will undergo DBS in the same way as is usually done but will receive this newer
battery with ability to record brain signals.

Inclusion criteria:

1. Medically-refractory neurologic disease amenable to therapy with deep brain
stimulation including:

1. Idiopathic Parkinson disease with motor fluctuation, dyskinesia, and/or medically
refractory tremor despite optimal medical management by a movement disorders
neurologist.

OR

2. Unilateral or bilateral mesial temporal lobe (hippocampal) epilepsy with complex
partial, and/or secondarily generalized seizures, that is:

- confirmed through a combination of interictal scalp EEG, ictal scalp EEG
under video monitoring, ictal SPECT scanning, and/or invasive EEG monitoring

- disabling seizure counts >2 per month documented over a 3 month period

- refractory to at least three antiepileptic drugs given at clinically
appropriate maintenance doses resulting in therapeutic plasma levels (in
cases where such levels have been established for that particular drug. Drug
failures because of side- effects will not be counted toward this total.

- determined to have mesial temporal lobe epilepsy that is not amenable to
resective surgery according to consensus opinion among epileptologists on
our institution's multidisciplinary Epilepsy Surgery Committee

2. Mayo Clinic Deep Brain Stimulation Committee approval for bilateral deep brain
stimulation therapy obtained on routine clinical grounds and without reference to this
protocol.

3. Age 18 to 75.

4. Ability and willingness to provide informed consent and participate in the study
protocol.

Exclusion criteria:

1. Diagnoses other than those included in #1 above.

2. Comorbid nonepileptic behavioral events or psychogenic movement disorder.

3. Medical contraindications to DBS surgery.

4. Psychiatric comorbidities not under stable medical therapy.

5. Neurodegenerative dementia (cognitive dysfunction resulting from frequent seizure
activity will not be an exclusion criteria).

6. Implanted electronically active medical device with the potential to interfere with
intracranial recordings (ex. pacemaker, automatic implantable cardioverter
defibrillator (AICD), active vagal nerve stimulator).

7. Pregnancy; women of child-bearing potential will be required to commit to using an
effective method of contraception during the entire duration of the trial. If a
subject becomes pregnant despite these precautions, she will be required to report
that to our center within two weeks at which point explantation of the experimental
device would be an option.