Anatomical predictors of cognitive decline after subthalamic stimulation in Parkinson’s disease

Abstract

We investigated whether pre-operative MRI measures of focal brain atrophy could predict cognitive decline occurring after deep brain stimulation (DBS) of the subthalamic nucleus (STN) in patients with Parkinson's disease (PD). For that purpose, we prospectively collected data of 42 consecutive patients with PD who underwent bilateral STN-DBS. Normalized brain structure volumes and cortical thicknesses were measured on pre-operative T1-weighted MRI. Patients were tested for their cognitive performances before surgery and 1 year after. After controlling for age, gender, pre-operative disease severity, change in dopaminomimetic dose after surgery and contact location, we found correlations: (1) between the variation of the total Mattis dementia rating scale (MDRS) score and left lateral ventricle volume (p = 0.032), (2) between the variation of the initiation/perseveration subscore of the MDRS and the left nucleus accumbens volume (p = 0.042) and the left lateral ventricle volume (p = 0.017) and (3) between the variation of the backward digit-span task and the right and left superior frontal gyrus thickness (p = 0.004 and p = 0.007, respectively). Left nucleus accumbens atrophy was associated with decline in the initiation/perseveration subscore with the largest effect size (d = - 1.64). Pre-operative left nucleus accumbens volume strongly predicted postoperative decline in the initiation/attention subscore (AUC = 0.92, p < 0.001, 96.3% sensitivity, 80.0% specificity, 92.9% PPV and 92.9% NPV). We conclude that the morphometric measures of brain atrophy usually associated with cognitive impairment in PD can also explain or predict a part of cognitive decline after bilateral STN-DBS. In particular, the left accumbens nucleus volume could be considered as a promising marker for guiding surgical decisions.

A systematic review of brain morphometry related to deep brain stimulation outcome in Parkinson’s disease

“… 8.8 ± 2.0 mo Med off: 39.2 ± 19.1 NR Blume; 2017 29 40 (30/10) BL STN 12.5 ± 4.5 61.8 ± 6.7 ↑ WML & Rapid onset of dementia within 1 yr. ↑ WML & Increased rate of decline in cognitive composite score within 3 yr. 3 yr Med off: 33.6 ± 10.7; Med on:12.2 ± 6.6 Med NR: PDpD after 3 yr:34.8 ± 11.3 NC or MCI after 3 yr:30.2 ± 7.8 Puy; 2018 31 Case study (1, female) STN 7 68 A medial temporal lobe atrophy score of 2 of the patient who developed dementia after deep brain stimulation. / Med off:30 / Planche; 2018 15 42 (26/16) BL STN 10 [6–17] 64 [45–70] ↓ The left nucleus accumbens & The variation of the initiation/perseveration subscore of the MDRS. ↑ The left lateral ventricle & The variation of the total MDRS score/ the initiation/perseveration subscore.…”

“…Eight studies that were included in our review reported associations of brain volumetry with the cognitive outcome 15 , 22 , 28 – 33 . ROI analysis assessing specific structures was adopted in these studies.…”

“…Apart from the hippocampus and thalamus, atrophy of the nucleus accumbens was also suggested to correlate with cognitive decline after DBS 15 . The atrophy of left nucleus accumbens predicted postoperative decline in executive functions of patients after STN-DBS in 1 year 15 . Presurgical left nucleus accumbens volume was strongly correlated with the variation in the MDRS initiation/perseveration subscore.…”

“…Connections between hippocampal subfields with cognitive functions and motor subtypes of PD patients have been proposed, the study of which might exert increased potential in patient selection with candidate stratified to different motor subtypes 65 , 66 . Other brain structures were also reported to correlate with the cognitive outcome of DBS, including thalamus 30 , nucleus accumbens 15 and NBM 33 . These structures provide important crossroads for cognition-relevant information processing.…”

Nucleus basalis of Meynert predicts cognition after deep brain stimulation in Parkinson's disease

“…A recent autopsy study on 25 postmortem brains of PD-MCI patients by Knox and colleagues, however, found a broad variety of pathological changes including α-synuclein and cholinergic pathology as well as cerebral amyloid angiopathy [26]. Therefore, it could be interesting to look further into other pathologies like white matter lesions and their underlying risk factors and into the size and integrity of other non-cholinergic structures discussed to play a role in cognition in PD like the nucleus accumbens [27] and the pulvinar [28].…”