Acute changes in mood induced by subthalamic deep brain stimulation in Parkinson disease are modulated by psychiatric diagnosis

Abstract

Background: Deep brain stimulation of the subthalamic nucleus (STN DBS) reduces Parkinson disease (PD) motor symptoms but has unexplained, variable effects on mood.

Objective: The study tested the hypothesis that pre-existing mood and/or anxiety disorders or increased symptom severity negatively affects mood response to STN DBS.

Methods: Thirty-eight PD participants with bilateral STN DBS and on PD medications were interviewed with Structured Clinical Interview for DSM-IV-TR Axis I Disorders (SCID) and completed Beck Depression Inventory (BDI) and Spielberger State Anxiety Inventory (SSAI) self-reports. Subsequently, during OFF and optimal ON (clinical settings) STN DBS conditions and while off PD medications, motor function was assessed with the United Parkinson Disease Rating Scale (UPDRS, part III), and participants rated their mood with Visual Analogue Scales (VAS), and again completed SSAI. VAS mood variables included anxiety, apathy, valence and emotional arousal.

Results: STN DBS improved UPDRS scores and mood. Unexpectedly, PD participants diagnosed with current anxiety or mood disorders experienced greater STN DBS-induced improvement in mood than those diagnosed with remitted disorders or who were deemed as having never met threshold criteria for diagnosis. BDI and SSAI scores did not modulate mood response to STN DBS, indicating that clinical categorical diagnosis better differentiates mood response to STN DBS than self-rated symptom severity. SCID diagnosis, BDI and SSAI scores did not modulate motor response to STN DBS.

Conclusions: PD participants diagnosed with current mood or anxiety disorders are more sensitive to STN DBS-induced effects on mood, possibly indicating altered basal ganglia circuitry in this group.

Keywords: Anxiety disorder; Deep brain stimulation; Mood; Mood disorder; Parkinson disease; Subthalamic nucleus.

Figure 1

Experimental procedure detailing interviews, self-report questionnaires, motor assessment, and computer tasks (Visual Analogue Scales self-ratings) from which dependent variables were obtained. Participants underwent contact manipulation conditions 1–7 days after the Initial Interview. In the case of participants who underwent 2 days of stimulation conditions, OFF STN DBS dependent measure scores were obtained by averaging across both OFF conditions.

Figure 2

Three-dimensional distribution of clinically optimized STN DBS electrode contacts for the sample studied (N = 38). They are presented (A) coronally and (B) sagittally, overlaid on the Mai atlas [25], 17.2 mm posterior to the anterior commissure. For display purposes, a 0.75 mm radius sphere was centered on each contact location. Violet = STN; red spheres = right electrode contact locations; green spheres = left electrode contact locations.

Figure 3

Acute effects of STN DBS on mood and motor behavior. Relative to OFF DBS (off PD medications), clinically optimal STN DBS (off PD medications) (A) improved motor symptoms, (B, D) decreased anxiety and apathy, and (C) increased valence (improved mood), but had no effect on emotional arousal. Mean + SEM shown. *, p < 0.05, **, p < 0.01, ***, p < 0.001 relative to OFF. VAS, visual analogue scale; SSAI, Spielberger State Anxiety Inventory; UPDRS, United Parkinson’s Disease Rating Scale.

Figure 4

STN DBS-induced improvements in mood are greater in participants with current anxiety or mood disorder diagnoses relative to participants with remitted diagnoses or deemed never to have met threshold criteria for diagnosis. Optimal ON, off medication STN DBS-induced improvements in self-rated (A) valence but not arousal and (B) anxiety but not apathy were significantly elevated in currently diagnosed participants relative to remitted and never diagnosed groups. Mean + SEM shown. *, p < 0.05 relative to no diagnosis ever; ^##p < 0.01 relative to remitted diagnosis.