Effects of STN and GPi Deep Brain Stimulation on Impulse Control Disorders and Dopamine Dysregulation Syndrome

Impulse control disorders (ICDs) and dopamine dysregulation syndrome (DDS) are important behavioral problems that affect a subpopulation of patients with Parkinson's disease (PD) and typically result in markedly diminished quality of life for patients and their caregivers. We aimed to investigate the effects of subthalamic nucleus (STN) and internal globus pallidus (GPi) deep brain stimulation (DBS) on ICD/DDS frequency and dopaminergic medication usage.A retrospective chart review was performed on 159 individuals who underwent unilateral or bilateral PD DBS surgery in either STN or GPi. According to published criteria, pre- and post-operative records were reviewed to categorize patients both pre- and post-operatively as having ICD, DDS, both ICD and DDS, or neither ICD nor DDS. Group differences in patient demographics, clinical presentations, levodopa equivalent dose (LED), and change in diagnosis following unilateral/bilateral by brain target (STN or GPi DBS placement) were examined.28 patients met diagnostic criteria for ICD or DDS pre- or post-operatively. ICD or DDS classification did not differ by GPi or STN target stimulation. There was no change in DDS diagnosis after unilateral or bilateral stimulation. For ICD, diagnosis resolved in 2 of 7 individuals after unilateral or bilateral DBS. Post-operative development of these syndromes was significant; 17 patients developed ICD diagnoses post-operatively with 2 patients with pre-operative ICD developing DDS post-operatively.Unilateral or bilateral DBS did not significantly treat DDS or ICD in our sample, even though a few cases of ICD resolved post-operatively. Rather, our study provides preliminary evidence that DDS and ICD diagnoses may emerge following DBS surgery

Deep Brain Stimulation for Tremor Associated with Underlying Ataxia Syndromes: A Case Series and Discussion of Issues

Background: Deep brain stimulation (DBS) has been utilized to treat various symptoms in patients suffering from movement disorders such as Parkinson's disease, dystonia, and essential tremor. Though ataxia syndromes have not been formally or frequently addressed with DBS, there are patients with ataxia and associated medication refractory tremor or dystonia who may potentially benefit from therapy.Methods: A retrospective database review was performed, searching for cases of ataxia where tremor and/or dystonia were addressed by utilizing DBS at the University of Florida Center for Movement Disorders and Neurorestoration between 2008 and 2011. Five patients were found who had DBS implantation to address either medication refractory tremor or dystonia. The patient's underlying diagnoses included spinocerebellar ataxia type 2 (SCA2), fragile X associated tremor ataxia syndrome (FXTAS), a case of idiopathic ataxia (ataxia not otherwise specified [NOS]), spinocerebellar ataxia type 17 (SCA17), and a senataxin mutation (SETX).Results: DBS improved medication refractory tremor in the SCA2 and the ataxia NOS patients. The outcome for the FXTAS patient was poor. DBS improved dystonia in the SCA17 and SETX patients, although dystonia did not improve in the lower extremities of the SCA17 patient. All patients reported a transient gait dysfunction postoperatively, and there were no reports of improvement in ataxia‐related symptoms.Discussion: DBS may be an option to treat tremor, inclusive of dystonic tremor in patients with underlying ataxia; however, gait and other symptoms may possibly be worsened.Erratum published on July 27, 2016</p

Definitions of DDS, ICDs, and Punding.

<p>DDS; Dopamine dysregulation syndrome.</p><p>ICDs; Impulse control disorders.</p

Did Unilateral and Bilateral DBS Lead Placement Impact the Pre-operative Diagnosis of DDS?

<p>*DBS unilateral or bilateral lead target(s) noted in parentheses.</p><p>**Patient did not have bilateral DBS lead placement.</p><p>DRT; dopamine replacement therapy including levodopa and/or dopamine agonists.</p

Baseline Demographics and Characteristics for All Patients in the Cohort.

<p>MEDICATION; all PD medications.</p

Did Unilateral and Bilateral DBS Lead Placement Impact the Pre-operative Diagnosis of ICD?

<p>*DBS unilateral or bilateral lead target(s) noted in parentheses.</p><p>**Patient had simultaneous bilateral DBS lead placement. No diagnostic assessment was possible for the patient after unilateral placement.</p><p>***Patient did not have bilateral DBS lead placement.</p><p>DRT; dopamine replacement therapy including levodopa and/or dopamine agonists.</p