Does Personality Change Follow Deep Brain Stimulation in Parkinson's Disease Patients?

Implanted cortical neuroprosthetics for speech and movement restoration

Implanted cortical neuroprosthetics (ICNs) are medical devices developed to replace dysfunctional neural pathways by creating information exchange between the brain and a digital system which can facilitate interaction with the external world. Over the last decade, researchers have explored the application of ICNs for diverse conditions including blindness, aphasia, and paralysis. Both transcranial and endovascular approaches have been used to record neural activity in humans, and in a laboratory setting, high-performance decoding of the signals associated with speech intention has been demonstrated. Particular progress towards a device which can move into clinical practice has been made with ICNs focussed on the restoration of speech and movement. This article provides an overview of contemporary ICNs for speech and movement restoration, their mechanisms of action and the unique ethical challenges raised by the field.

Developments in the prediction of cognitive changes following deep brain stimulation in persons with Parkinson's disease

INTRODUCTION

Deep brain stimulation (DBS) is an effective treatment for Parkinson's disease (PD) motor symptoms that improves function and quality of life in appropriately selected patients. Because mild to moderate cognitive declines can follow DBS and impact quality of life in a minority of patients, an important consideration involves the cognitive deficit and its prediction.

AREAS COVERED

The author briefly summarizes cognitive outcomes from DBS and reviews in more detail the risks/predictors of post-DBS cognitive dysfunction by mainly focusing on work published between 2018 and 2024 and using comprehensive neuropsychological (NP) evaluations. Most publications concern bilateral subthalamic nucleus (STN) DBS. Comment is offered on challenges and potential avenues forward.

EXPERT OPINION

STN DBS is relatively safe cognitively but declines occur especially in verbal fluency and executive function/working memory. Numerous predictors and risk factors for cognitive outcomes have been identified (age and pre-operative neuropsychological status appear the most robust) but precise risk estimates cannot yet be confidently offered. Future studies should employ study center consortia, follow uniform reporting criteria (to be developed), capitalize on advances in stimulation, biomarkers, and artificial intelligence, and address DBS in diverse groups. Advances offer an avenue to investigate the amelioration of cognitive deficits in PD using neuromodulation.

Public Perceptions of Neurotechnologies Used to Target Mood, Memory, and Motor Symptoms

Background

Advances in the development of neurotechnologies have the potential to revolutionize treatment of brain-based conditions. However, a critical concern revolves around the willingness of the public to embrace these technologies, especially considering the tumultuous histories of certain neurosurgical interventions. Therefore, examining public attitudes is paramount to uncovering potential barriers to adoption ensuring ethically sound innovation.

Methods

In the present study, we investigate public attitudes towards the use of four neurotechnologies (within-subjects conditions): deep brain stimulation (DBS), transcranial magnetic stimulation (TMS), pills, and MRI-guided focused ultrasound (MRgFUS) as potential treatments to a person experiencing either mood, memory, or motor symptoms (between-subjects conditions). US-based participants (N=1052; stratified to be nationally representative based on sex, race, age) were asked about their perceptions of risk, benefit, invasiveness, acceptability, perceived change to the person, and personal interest in using these neurotechnologies for symptom alleviation.

Results

Descriptive results indicate variability between technologies that the U.S. public is willing to consider if experiencing severe mood, memory, or motor symptoms. The main effect of neurotechnology revealed DBS was viewed as the most invasive and risky treatment and was perceived to lead to the greatest change to who someone is as a person. DBS was also viewed as least likely to be personally used and least acceptable for use by others. When examining the main effects of symptomatology, we found that all forms of neuromodulation were perceived as significantly more beneficial, acceptable, and likely to be used by participants for motor symptoms, followed by memory symptoms, and lastly mood symptoms. Neuromodulation (averaging across neurotechnologies) was perceived as significantly riskier, more invasive, and leading to a greater change to person for mood versus motor symptoms; however, memory and motor symptoms were perceived similarly with respect to risk, invasiveness, and change to person.

Conclusion

These results suggest that the public views neuromodulatory approaches that require surgery (i.e., DBS and MRgFUS) as riskier, more invasive, and less acceptable than those that do not. Further, findings suggest individuals may be more reluctant to alter or treat psychological symptoms with neuromodulation compared to physical symptoms.

Essentials of Informed Consent to Psychedelic Medicine

Importance

Interest in administering psychedelic agents as mental health treatment is growing rapidly. As drugmakers invest in developing psychedelic medicines for several psychiatric indications, lawmakers are enacting legal reforms to speed access globally, and health agencies are preparing to approve these treatments. Meanwhile, US states, such as Oregon and Colorado, are making psychedelics available for supervised use outside the conventional health care system.

Observations

Despite legal change and potentially imminent regulatory approval in some countries, standards for integrating psychedelics into health care have lagged, including norms for designing and implementing informed consent processes. Informed consent is complicated by the unique features of psychedelics and their means of administration. Because no governments have approved any classic psychedelics for general medical or psychiatric use, only clinical researchers have obtained informed consent from trial participants. Accordingly, there is an unmet need for informed consent processes tailored to the challenges of administering psychedelics in nonresearch settings.

Conclusions and Relevance

Analysis of the challenges of designing and implementing psychedelic informed consent practices revealed 7 essential components, including the possibility of short- and long-term perceptual disturbances, potential personality changes and altered metaphysical beliefs, the limited role of reassuring physical touch, the potential for patient abuse or coercion, the role and risks of data collection, relevant practitioner disclosures, and interactive patient education and comprehension assessment. Because publicly available informed consent documents for psychedelic clinical trials often overlook or underemphasize these essential elements, sample language and procedures to fill the gap are proposed.

Energy Delivered by Subthalamic Deep Brain Stimulation for Parkinson Disease Correlates With Depressive Personality Trait Shift

OBJECTIVES

Despite the large amount of literature examining the potential influence of subthalamic nucleus deep brain stimulation (STN-DBS) on psychiatric symptoms and cognitive disorders, only a few studies have focused on its effect on personality. We investigated the correlation between total electrical energy delivered (TEED) and the occurrence of depressive traits in patients with Parkinson disease (PD) after one year of DBS.

MATERIALS AND METHODS

Our study involved 20 patients with PD (12 women, mean [±SD] age 57.60 ± 7.63 years) who underwent bilateral STN-DBS, whose personality characteristics were assessed using the Minnesota Multiphasic Personality Inventory-2 (MMPI-2), according to the core assessment program for surgical interventional therapies in Parkinson's disease (CAPSIT-PD) procedure.

RESULTS

We found that despite a marked improvement in motor functions and quality of life after 12 months, patients showed a significant increase in MMPI-2 subscales for depression (D scale and Depression scale) and in other content component scales (low self-esteem, work interference, and negative treatment indicators). Interestingly, only the TEED on the right side was inversely correlated with the changes in scale D (r_s = -0.681, p = 0.007), whereas depressive traits did not correlate with disease duration, levodopa equivalent daily dose (LEDD) reduction, patient's age, or severity of motor symptoms.

CONCLUSIONS

Our preliminary observations indicate that despite the excellent motor outcome and general improvement in quality of life, DBS treatment can result in patients poorly adjusting to their personal, familiar, and socio-professional life. Different influences and multiple factors (such as TEED, intra/postsurgical procedure, coping mechanisms, and outcome expectations) may affect depressive traits. Further advances are expected to improve stimulation methods.

Risk Factors for Delirium after Deep Brain Stimulation Surgery under Total Intravenous Anesthesia in Parkinson's Disease Patients

BACKGROUND

Postoperative delirium (POD) is associated with perioperative complications and mortality. Data on the risk factors for delirium after subthalamic nucleus deep brain stimulation (STN-DBS) surgery is not clarified in Parkinson's disease (PD) patients receiving total intravenous anesthesia. We aimed to investigate the risk factors for delirium after STN-DBS surgery in PD patients.

METHODS

The retrospective cohort study was conducted, including 131 PD patients who underwent STN-DBS for the first time under total intravenous anesthesia from January to December 2021. Delirium assessments were performed twice daily for 7 days after surgery or until hospital discharge using the confusion assessment method for the intensive care unit. Multivariate logistic regression analysis was used to determine the risk factor of POD.

RESULTS

In total, 22 (16.8%) of 131 patients were in the POD group, while the other 109 patients were in the Non-POD group. Multivariate logistic regression analysis showed that preoperative Mini-mental State Examination score [odds ratio = 0.855, 95% confidence interval = 0.768-0.951, p = 0.004] and unified Parkinson's disease rating scale part 3 (on state) score (odds ratio = 1.061, 95% confidence interval = 1.02-1.104, p = 0.003) were independently associated with delirium after surgery.

CONCLUSIONS

In this retrospective cohort study of PD patients, a lower Mini-mental State Examination score and a higher unified Parkinson's disease rating scale part 3 (on state) score were the independent risk factors for delirium after STN-DBS surgery in PD patients under total intravenous anesthesia.

Concerns About Psychiatric Neurosurgery and How They Can Be Overcome: Recommendations for Responsible Research

Background

Psychiatric neurosurgery is experiencing a revival. Beside deep brain stimulation (DBS), several ablative neurosurgical procedures are currently in use. Each approach has a different profile of advantages and disadvantages. However, many psychiatrists, ethicists, and laypeople are sceptical about psychiatric neurosurgery.

Methods

We identify the main concerns against psychiatric neurosurgery, and discuss the extent to which they are justified and how they might be overcome. We review the evidence for the effectiveness, efficacy and safety of each approach, and discuss how this could be improved. We analyse whether and, if so, how randomised controlled trials (RCTs) can be used in the different approaches, and what alternatives are available if conducting RCTs is impossible for practical or ethical reasons. Specifically, we analyse the problem of failed RCTs after promising open-label studies.

Results

The main concerns are: (i) reservations based on historical psychosurgery, (ii) concerns about personality changes, (iii) concerns regarding localised interventions, and (iv) scepticism due to the lack of scientific evidence. Given the need for effective therapies for treatment-refractory psychiatric disorders and preliminary evidence for the effectiveness of psychiatric neurosurgery, further research is warranted and necessary. Since psychiatric neurosurgery has the potential to modify personality traits, it should be held to the highest ethical and scientific standards.

Conclusions

Psychiatric neurosurgery procedures with preliminary evidence for efficacy and an acceptable risk–benefit profile include DBS and micro- or radiosurgical anterior capsulotomy for intractable obsessive–compulsive disorder. These methods may be considered for individual treatment attempts, but multi-centre RCTs are necessary to provide reliable evidence.