How and When to Consider DBS in the Older Patient Erwin B. Montgomery, Jr. MD The Dr. Sigmund Rosen Scholar and Professor of Neurology University of Alabama at Birmingham

July 1, 2013 Medical Director Greenville Neuromodulation Center Greenville Neuromodulation Scholar in Neuroscience and Philosophy Thiel College Greenville, PA

Disclaimers and Conflict of Interest Material grants from Medtronic Neuromodulation Inc. Consultant to Great Lakes Neurotechnology Consultant Greenville Neuromodulation Services Consultant FHC, Inc.

Experimental and Off-label Uses Off-label uses of FDA approved devices and experimental and investigational uses will be identified when discussed The role of the FDA is to regulate the interstate commerce in drugs and devices; not to regulate the practice of medicine

Deep Brain Stimulation (DBS) Implantation of chromic electrical stimulation electrodes in various targets in the brain for the relief of symptoms and disabilities in neurological and psychiatric disease

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DBS The brain is basically an electrical device Processes information electronically Neurotransmitters (basis for pharmacology) are the messengers not the message Disease is misinformation

DBS Unparalleled accuracy and precision Spatial resolution on millimeters Temporal resolution on the order of milliseconds

DBS Indications in the Elderly The same as any age group Certain indications more common in elderly Primary affect of age is in the co-morbidities Benefit may not be a much Increased risks NO specific age limit

Figure 2 Predictors of effective bilateral subthalamic nucleus stimulation for PD. Charles, PD; Van Blercom, N; Krack, P; Lee, SL; MD, PhD; Xie, J; Besson, G; Benabid, A-L; MD, PhD; Pollak, P Neurology. 59(6):932-934, September 24, 2002. Figure 2 . Scatter plot and linear regression with 95% confidence interval shown with the R2 value, i.e., the percent of the variation in improvement from stimulation accounted for by age. Individual data points are represented as black squares (n = 54 patients). Data values were calculated as in figure 1. The correlation coefficient, r (Spearman's rho), is significant at the 0.01 level (two-tailed). ©2002 American Academy of Neurology. Published by LWW_American Academy of Neurology. 2

Issue of Pre-existing Cognitive Decline Concerns based on informed speculation It just makes sense that invading the brain is going to make cognitive function worse even if not known complication such as intra-cerebral hemorrhage or stroke Essentially untested Most exclude patients with cognitive decline so hypothesis not tested

DBS effects on Cognitive Function Only demonstrated consistent decline is in verbal fluency which is mild to moderate in severity Liberalization of cognitive requirements

DBS in Parkinson’s Disease More effective and less long-term side effects than best medical therapy 2-3% risk of severe or permanent adverse effect Intra-cerebral hemorrhage Infection Rare complications Seizures Hardware failure

DBS in Parkinson’s Disease Candidate criteria Idiopathic Parkinson’s disease Issue of atypical parkinsonism Exhausted reasonable attempts at medication therapy Parkinson related disability is the “rate limiting” condition, not cognition Able to tolerate surgery

Exhausted Reasonable Attempts at Medication Therapy Very problematic Thousands of potential combinations Think in terms of drug class rather than individual agents Dopamine agonists Is issue lack of efficacy or side effect Agents within class relatively the same efficacy Special case in extended or long acting agents differ in side effects

Current and Future Indications FDA approved Parkinson’s disease Essential tremor Dystonia Obsessive-compulsive disorder Off-label uses Hemiballismus Chorea Tardive dyskinesia Tardive dystonia Cerebellar outflow tremor Hyperkinetic disorders Experimental or investigational Alzheimer's disease Epilepsy Depression Stroke

Role of the Gerontologist, Internist, Family Practitioner Team Patient referred for evaluation not DBS surgery Refer to Movement Disorders/DBS expert not surgeon Major selection criteria is medical not surgical Low threshold Movement Disorders/DBS expert = high threshold

Questions?