Deep Brain Stimulation and Swimming Performance: A Randomized Within-Person Crossover Study

Abstract

Objective: To determine whether deep brain stimulation (DBS) causes swimming impairment, we systematically compared swimming ability between DBS on vs off in 18 patients.

Methods: We conducted a randomized blinded crossover study, comparing swimming ability between DBS on vs off, within participants. Participants swam 3 laps of front crawl and 3 laps of breaststroke. Prespecifed primary outcomes were proportion of lap completed, lap time, and Aquatic Skills Proficiency Assessment (ASPA) score. Prespecified secondary outcomes were a qualitative description of marked changes observed.

Results: Eighteen participants with Parkinson disease (n = 13), essential tremor (n = 3), Tourette syndrome (n = 1), or posttraumatic brain injury proximal tremor (n = 1), treated with posterior subthalamic area (n = 15) or globus pallidus interna (n = 3) DBS were assessed. There was no significant effect of DBS on/off status on any outcome measure for front crawl or breaststroke. Three participants showed changes in both qualitative and quantitative assessments. Of these, 1 participant displayed reduction in swimming ability: impairment in all outcomes with DBS on, normalizing with DBS off (the same individual as previously reported). The participant displayed difficulty coordinating limb movement as well as postural control. Two participants showed improvements in lap time and ASPA scores with DBS on.

Conclusion: Overall DBS did not impair swimming performance, although 1 patient demonstrated a stimulation-induced drowning hazard. There were no anatomic or clinical features unique to the individual with swimming impairment. Patients should be warned about the possibility of DBS-induced drowning hazard and should swim with capable supervision after DBS.

Classification of evidence: This study provides Class IV evidence that for patients with implanted DBS electrodes, the stimulation on condition, compared with stimulation off, did not significantly impair swimming performance. A formal assessment of unblinding would have been helpful.

Figure 1. Flowchart of Participant Assessment

Figure 2. Schematic of Electrode Contacts Active During Assessment

Electrode contacts plotted over axial sections of the Schaltenbrand and Wahren atlas. Index case electrodes depicted in red, and all other participants depicted in blue. Circles (o) indicate left brain contacts, and crosses (+) indicate right brain contacts. (A) Axial section 0.5 mm above the midcommisural point. (B) Axial section 1.0 mm below the midcommisural point. (C) Axial section 3.5 mm below the midcommisural point. (D) Axial section 4.5 mm below the midcommisural point. Abbreviations: B.cj, brachium conjunctivum; Cpip, internal capsule, posterior limb; H1 and H2, field H1 and H2 of Forel; Ppd, nucleus peripeduncularis; Q, fasciculus Q; Rt, reticular thalamic nucleus; Ru, red nucleus; Sth, subthalamic nucleus; Raprl, prelemniscal radiation; Ru: red nucleus; T mth, mammillo-thalamic tract; Vim.e, external Vim; Vom, ventralis oralis medialis; Vop, ventralis oralis posterior; Zi, zona incerta. A = anterior; M = medial; P = posterior, L = lateral. Atlas images from Schaltenbrand G, & Wahren W. Atlas for Stereotaxy of the Human Brain. Stuttgart: Georg Thieme Verlag KG; 1977.