Table 2. DBS effects on cognitive impairment and mood in patients with PD.
| Author | Year | Outcome measure | Type of study | No. of patients | Results after DBS |
|---|---|---|---|---|---|
| Rizzone et al.38 | 2014 | Secondary: cognition and mood MMSE, RPM, digit span forward, phonological fluency, Corsi’s block-tapping test forward/backward MWCST, RAVLT, SAS, SDS, BDI and STAI | 11-year prospective multicenter | 26 STN | Remarkable decline in phonological fluency, slight decline in cognition. No significant changes in depression. Contradictory results in anxiety. |
| Oderkerken et al.39 | 2013 | Primary: cognition and mood Composite score (cognitive tests, loss of professional activity, work, or job; loss of important relationships; psychosis, depression, or anxiety for 3 months or longer as by MINI) | 1-year randomized controlled trial | 128 (63 GPi) (65 STN) | No statistically significant difference between GPi and STN groups. |
| Lhommée et al.43 See ref. 51 | 2012 | Secondary: cognition mood, behavior and NMF. MDRS, Frontal Score (MWCST, verbal fluency, graphic and motor series) MINI, Ardouin Scale, BDI, BAI and SAS1 | 1-year prospective Multicenter | 63 STN | Overall cognition unchanged. Reduction in verbal fluency. Improvement in MWCST. Depression and anxiety improved. |
| McDonald et al.41 | 2012 | Primary: mood VAMS | Cross-sectional On/off DBS | 34 (23 STN) (11 BMT) | Mood, anxiety, apathy and fatigue improve with STN DBS ON. |
| Follett et al.3 | 2010 | Secondary: cognition and mood WAIS III and BDI-II | 2-year randomized prospective multicenter | 299 (152 GPi) (147 STN) | Similarly slight decrements in cognitive function in STN and GPi DBS group. Depression worsened after SNT-DBS and improved after GPi DBS. |
| Williams et al.32 | 2010 | Secondary: cognition DRS-II, D-KEFS and WAIS | 1-year randomized prospective open-label | 366 (182 STN) (183 BMT) | No difference between STN-DBS and BMT groups in DRS-II scores. Small significant decrease in verbal fluency in STN versus BMT. |
| Weaver et al.2 | 2009 | Secondary: cognition and mood MDRS, WAIS, verbal associative fluency, Stroop Test, WCST, Boston Naming Test, Brief Visuospatial Memory Test, Hopkins Verbal Learning Test. BDI | 6 months randomized controlled | 255 (60 STN) (61 GPi) (134 BMT) | Neither treatment was associated with significant change in cognition or depression. |
| Witt et al.30 | 2008 | Primary: cognition MDRS, RAVLT (German), WAIS Benton visual retention, stroop test, verbal fluency | 6 months randomized multicentre | 123 (60STN) (63BMT) | STN DBS does not reduce overall cognition. Selective decrease in frontal cognitive functions. Anxiety improves in the STN group compared to BMT group. |
| Kaiser et al.42 | 2008 | Primary: Mood and psychosocial function POMS, BDI, STAI-X1/X2, SCL-90-R and SIP | 3-year prospective | 33 STN | No change in mood or psychosocial functioning. A cluster analysis revealed 4 different psychosocial profiles that remain stable after surgery. |
| Appleby et al.31 | 2007 | Secondary: cognition, depression, behavior Neuropsychiatric tests, psychiatric side effects | Meta-analysis 546 articles published between 1996–2005 | 10,339 DBS | Reported rates of depression, cognitive impairment, mania, and behavior changes are low. High rate of suicide in patients treated with DBS. |
| Deuschl et al.1 | 2006 | Secondary: cognition and mood MDRS, Montgomery and Asberg DRS, Brief Psychiatric Rating Scale | 6-month randomized-pairs trial | 156 78 STN 78 BMT | Emotional and cognitive measures did not differ significantly. |
| Parsons et al.29 | 2006 | Primary: cognition Neuropsychiatric tests | Meta-analysis 20 articles published between 1990–2005 | 612 STN | STN-DBS results in slight decrease in executive functions and working memory. |
| Castelli et al.37 | 2006 | Primary: Cognition, mood, psych disorders RCM, Bisyllabic Word Repetition Test, Corsi's Block-Tapping Test, Paired-Associate Learning, Trail Making-B, NMCST, verbal fluency tasks,BDI, STAI and SCID-II | 15-month prospective | 72 STN | No overall cognitive change. Mild decrease in verbal fluency. Small improvement in depression and obsessive-compulsive and paranoid personality traits. |
| Funkiewitz et al.36 | 2004 | Primary: cognition, mood and behavior MDRS, WCST, verbal fluency graphic and motor series, BDI, UPDRS I | 3-year prospective | 77 STN | No global cognitive deterioration. Verbal fluency decline. |
| Krack et al.34 | 2003 | Secondary: cognition MDRS, BDI, Clinical interview | 5-year prospective | 49 STN | Cognitive function changes between year 1–5 are consistent with progression of PD. |
| Daniele et al.35 | 2003 | Primary: cognitive MMSE and MWCST Corsi’s block-tapping test, RAVLT Clinical Interview | 12-month prospective | 20 STN | No change in global cognitive function. |
| Pillon B et al.33 | 2000 | Primary: cognition MDRS, Grober and Buschke, MWCST, Stroop test, trail making, verbal fluency, CANTAB BDI | 1-year prospective multicenter+cross-sectional (off/on DBS) | 56 (48-STN) (8-GPi) 20 (15 STN) (5 GPi) | STN patients had no cognitive deficit at 12 months, except for lexical fluency. There was no differential effect of STN or GPi stimulation. With STN DBS on: mild but significant improvement in psychomotor speed and working memory. |
Abbreviations: BAI, Beck Anxiety Inventory; BDI, Beck Depression Inventory; BMT, best medical therapy; UNI, unilateral; CANTAB, Cambridge Neuropsychological Test Automated Battery; D-KEFS, Delis-Kaplan Executive function system; DBS, deep brain stimulation; DRS, Depression Rating Scale; DRS-II, dementia rating scale-II; DSM-IV, Diagnostic and Statistical Manual of Mental Disorders, fourth edition; GPi, globus pallidus interna; MDRS, Mattis Dementia Rating Scale; MINI, Mini-international Neuropsychiatric Interview; MMSE, Mini-Mental State Exam; MWCST, Modified Wisconsin Card Sorting Test; NMCST, Nelson Modified Card Sorting Test; NMF, non-motor fluctuations; POMS, Profile of Mood Scale; RAVLT, Rey’s Auditory Verbal Learning Test; RPM, Raven’s Progressive Matrices; SAS, Zung’s Self-rating Anxiety Scale; SAS1, Starkstein Apathy Scale; SCID-II, Structured Clinical Interview for the DSM-III-R Axis II Disorders; SCL-90-R, Self-Report Symptom Inventory 90 Items-Revised; SDS, Zung’s Self-rating Depression Scale; SIP, Sickness Impact Profile (SIP); STAI, State Trait Anxiety Inventory; STN, subthalamic nucleus; UPDRS, Unified Parkinson's Disease Rating Scale; VAMS, Visual Analog Mood Scale; WAIS III, Wechsler Adult Intelligence Scales III.