Finding ways to decrease gait and speech impairment in patients with chronic STN DBS for Parkinson’s disease (P4.063)

Objective: To report the outcome of a DBS programming paradigm (PP) aimed at reducing gait, balance and speech impairment after prolonged STN DBS. Background: DBS of the STN using high frequency (130–185Hz) stimulation (HFS) is more effective for appendicular than axial symptoms. Low frequency stimulation (LFS) of the STN may reduce gait/balance impairment, but often results in worsening of appendicular symptoms. Medtronic DBS offers interleaving that allows delivery of two programs on each DBS lead. We used this to create a PP with a combination of low and high frequencies. Design/Methods: The novel PP (interlink-interleave, IL-IL) consists of two overlapping LFS programs on each DBS lead, with the overlapping area focused around the optimal contact. This area receives HFS controlling appendicular symptoms. The non-overlapping areas receives LFS potentially reducing gait/balance impairment and stimulation-induced-dysarthria. The Clinical-Global-Impression-of-Change (CGI-C) was completed retrospectively based on patient/caregiver feedback in patients remaining on IL-IL (at 3-months and current time). Results: Seventy-six patients were programmed with IL-IL (frequency 60–90Hz) from optimized HFS. Fifty-five (72%) patients remained on IL-IL after 18-months. These patients were separated into three categories: gait/balance impairment (n=48); stimulation-induced-dysarthria (n=17); and incomplete symptom control (n=14), with some belonging to more than one group. The median (range) CGI-C for gait was 2(1–5) at 3-months and 3(1–4) currently; for stimulation-induced-dysarthria 4(1–4) at 3-months and 4(1–5) currently, and for incomplete symptom control 2(1–3) at 3-months and 2(1–3) currently. Nine (12%) patients returned to conventional HFS after 5 days because of incomplete appendicular symptom control. Twelve (16%) patients have not returned for follow up. Conclusions: A significant number of patients chose to remain on IL-IL because of subjective improvements in balance/gait or dysarthria. Formal assessment with objective/quantitative outcome measures is currently under way and preliminary data will be presented. Disclosure: Dr. Karl has nothing to disclose. Dr. Verhagen Metman has nothing to disclose.