The Accuracy and Feasibility of Robotic Assisted Lead Implantation in Nonhuman Primates.

OBJECTIVES: Deep brain stimulation (DBS) and stereo-electroencephalography (SEEG) electrode implantation are the most important and frequent manipulations in nonhuman primates (NHP) neuromodulation research. However, traditional methods tend to be arduous and inaccurate. MATERIALS AND METHODS: Twelve adult male rhesus monkeys were selected for the study, with six subthalamic nucleus (STN) DBS, six anterior nucleus of the thalamus (ANT) DBS and six hippocampus-SEEG (Hippo-SEEG) electrodes implantation. Mean Euclidean errors of entrance and the target were calculated by postoperative image fusion, and the correlation between entrance and target error, as well as the differences among the various manipulations, were analyzed. The accuracy of target was further confirmed by gross anatomy examination. Moreover, the time consumption was recorded. RESULTS: The mean (±SD) Euclidean errors of the target point and entry point of the three manipulations were STN-DBS: 1.05 ± 0.54 mm and 0.52 ± 0.17 mm; ANT-DBS: 1.12 ± 0.74 mm and 0.58 ± 0.24 mm; and Hippo-SEEG: 2.68 ± 1.03 mm and 1.47 ± 0.63 mm. Significant differences were observed in both target and entry point errors between the DBS and Hippo-SEEG groups, with superior accuracy in the DBS group. The entrance errors had a significantly positive correlation with the target errors in the STN-DBS and Hippo-SEEG groups. Moreover, the time consumption in robotic surgery was much shorter than that in the traditional method, without any severe complications. CONCLUSION: The application of robot-assisted lead implantation in NHP neuromodulation research is feasible, accurate, safe, and efficient, and can prospectively be beneficial to neurological studies.

Sex modulates the outcome of subthalamic nucleus deep brain stimulation in patients with Parkinson's disease.

There are many documented sex differences in the clinical course, symptom expression profile, and treatment response of Parkinson's disease, creating additional challenges for patient management. Although subthalamic nucleus deep brain stimulation is an established therapy for Parkinson's disease, the effects of sex on treatment outcome are still unclear. The aim of this retrospective observational study, was to examine sex differences in motor symptoms, non-motor symptoms, and quality of life after subthalamic nucleus deep brain stimulation. Outcome measures were evaluated at 1 and 12 months post-operation in 90 patients with Parkinson's disease undergoing subthalamic nucleus deep brain stimulation aged 63.00 ± 8.01 years (55 men and 35 women). Outcomes of clinical evaluations were compared between sexes via a Student's t-test and within sex via a paired-sample t-test, and generalized linear models were established to identify factors associated with treatment efficacy and intensity for each sex. We found that subthalamic nucleus deep brain stimulation could improve motor symptoms in men but not women in the on-medication condition at 1 and 12 months post-operation. Restless legs syndrome was alleviated to a greater extent in men than in women. Women demonstrated poorer quality of life at baseline and achieved less improvement of quality of life than men after subthalamic nucleus deep brain stimulation. Furthermore, Hoehn-Yahr stage was positively correlated with the treatment response in men, while levodopa equivalent dose at 12 months post-operation was negatively correlated with motor improvement in women. In conclusion, women received less benefit from subthalamic nucleus deep brain stimulation than men in terms of motor symptoms, non-motor symptoms, and quality of life. We found sex-specific factors, i.e., Hoehn-Yahr stage and levodopa equivalent dose, that were related to motor improvements. These findings may help to guide subthalamic nucleus deep brain stimulation patient selection, prognosis, and stimulation programming for optimal therapeutic efficacy in Parkinson's disease.

Deep brain stimulation of the nucleus basalis of Meynert modulates hippocampal-frontoparietal networks in patients with advanced Alzheimer's disease.

BACKGROUND: Deep brain stimulation (DBS) of the nucleus basalis of Meynert (NBM) has shown potential for the treatment of mild-to-moderate Alzheimer's disease (AD). However, there is little evidence of whether NBM-DBS can improve cognitive functioning in patients with advanced AD. In addition, the mechanisms underlying the modulation of brain networks remain unclear. This study was aimed to assess the cognitive function and the resting-state connectivity following NBM-DBS in patients with advanced AD. METHODS: Eight patients with advanced AD underwent bilateral NBM-DBS and were followed up for 12 months. Clinical outcomes were assessed by neuropsychological examinations using the Mini-Mental State Examination (MMSE) and Alzheimer's Disease Assessment Scale. Resting-state functional magnetic resonance imaging and positron emission tomography data were also collected. RESULTS: The cognitive functioning of AD patients did not change from baseline to the 12-month follow-up. Interestingly, the MMSE score indicated clinical efficacy at 1 month of follow-up. At this time point, the connectivity between the hippocampal network and frontoparietal network tended to increase in the DBS-on state compared to the DBS-off state. Additionally, the increased functional connectivity between the parahippocampal gyrus (PHG) and the parietal cortex was associated with cognitive improvement. Further dynamic functional network analysis showed that NBM-DBS increased the proportion of the PHG-related connections, which was related to improved cognitive performance. CONCLUSION: The results indicated that NBM-DBS improves short-term cognitive performance in patients with advanced AD, which may be related to the modulation of multi-network connectivity patterns, and the hippocampus plays an important role within these networks. TRIAL REGISTRATION: ChiCTR, ChiCTR1900022324. Registered 5 April 2019-Prospective registration. https://www.chictr.org.cn/showproj.aspx?proj=37712.

Anterior thalamic nuclei deep brain stimulation inhibits mossy fiber sprouting via 3',5'-cyclic adenosine monophosphate/protein kinase A signaling pathway in a chronic epileptic monkey model.

BACKGROUND: Anterior thalamic nuclei (ATN) deep brain stimulation (DBS) is an effective method of controlling epilepsy, especially temporal lobe epilepsy. Mossy fiber sprouting (MFS) plays an indispensable role in the pathogenesis and progression of epilepsy, but the effect of ATN-DBS on MFS in the chronic stage of epilepsy and the potential underlying mechanisms are unknown. This study aimed to investigate the effect of ATN-DBS on MFS, as well as potential signaling pathways by a kainic acid (KA)-induced epileptic model. METHODS: Twenty-four rhesus monkeys were randomly assigned to control, epilepsy (EP), EP-sham-DBS, and EP-DBS groups. KA was injected to establish the chronic epileptic model. The left ATN was implanted with a DBS lead and stimulated for 8 weeks. Enzyme-linked immunosorbent assay, Western blotting, and immunofluorescence staining were used to evaluate MFS and levels of potential molecular mediators in the hippocampus. One-way analysis of variance, followed by the Tukey post hoc correction, was used to analyze the statistical significance of differences among multiple groups. RESULTS: ATN-DBS is found to significantly reduce seizure frequency in the chronic stage of epilepsy. The number of ectopic granule cells was reduced in monkeys that received ATN stimulation (P < 0.0001). Levels of 3',5'-cyclic adenosine monophosphate (cAMP) and protein kinase A (PKA) in the hippocampus, together with Akt phosphorylation, were noticeably reduced in monkeys that received ATN stimulation (P = 0.0030 and P = 0.0001, respectively). ATN-DBS also significantly reduced MFS scores in the hippocampal dentate gyrus and CA3 sub-regions (all P < 0.0001). CONCLUSION: ATN-DBS is shown to down-regulate the cAMP/PKA signaling pathway and Akt phosphorylation and to reduce the number of ectopic granule cells, which may be associated with the reduced MFS in chronic epilepsy. The study provides further insights into the mechanism by which ATN-DBS reduces epileptic seizures.