From prefrontal leukotomy to deep brain stimulation: the historical transformation of psychosurgery and the emergence of neuroethics

Neurosurgery for mental conditions and pain: An historical perspective on the limits of biological determinism

Neurosurgical operations treat involuntary movement disorders (MvDs), spasticity, cranial neuralgias, cancer pain, and other selected disorders, and implantable neurostimulation or drug delivery devices relieve MvDs, epilepsy, cancer pain, and spasticity. In contrast, studies of surgery or device implantations to treat chronic noncancer pain or mental conditions have not shown consistent evidence of efficacy and safety in formal, randomized, controlled trials. The success of particular operations in a finite set of disorders remains at odds with disconfirming results in others. Despite expectations that surgery or device implants would benefit particular patients, the normalization of unproven procedures could jeopardize the perceived legitimacy of functional neurosurgery in general. An unacknowledged challenge in functional neurosurgery is the limitation of biological determinism, wherein network activity is presumed to exclusively or predominantly mediate nociception, affect, and behavior. That notion regards certain pain states and mental conditions as disorders or dysregulation of networks, which, by implication, make them amenable to surgery. Moreover, implantable devices can now detect and analyze neural activity for observation outside the body, described as the extrinsic or micro perspective. This fosters a belief that automated analyses of physiological and imaging data can unburden the treatment of selected mental conditions and pain states from psychological subjectivity and complexity and the inherent sematic ambiguity of self-reporting. That idea is appealing; however, it discounts all other influences. Attempts to sway public opinion and regulators to approve deep brain stimulation for unproven indications could, if successful, harm the public interest, making demands for regulatory approval beside the point.

The Legacy of Egas Moniz: Triumphs and Controversies in Medical Innovation

António Egas Moniz, a pioneering Portuguese neurologist, is renowned for developing cerebral angiography and introducing the prefrontal leucotomy (lobotomy), for which he received the Nobel Prize in 1949. Initially hailed as a breakthrough for conditions like schizophrenia and severe anxiety, lobotomy later became controversial due to severe side effects, including irreversible personality changes. The advent of neuroleptics, such as chlorpromazine, in 1952 led to the decline of lobotomy in favor of more effective and humane treatments. Moniz's work raised significant ethical concerns, particularly regarding informed consent and the procedure's long-term impact, underscoring the need for continuous advancement and ethical considerations in psychiatric care. We present a narrative review of Egas Moniz's life and his pioneering discovery of cerebral angiography, which had a significant impact and a lasting legacy in neurology. Additionally, we highlight the evolution of alternative brain surgeries that arose from modifications of his original prefrontal leucotomy.

Deep brain stimulation for substance use disorder: a systematic review and meta-analysis

Objective

Substance use disorder (SUD) is a significant public health issue with a high mortality rate. Deep brain stimulation (DBS) has shown promising results in treating SUD in certain cases. In this study, we conducted a meta-analysis to evaluate the efficacy of DBS in the treatment of SUD and reduction of relapse rates.

Methods

We performed a thorough and methodical search of the existing scientific literature, adhering to the PRISMA guidelines, to identify 16 original studies that fulfilled our inclusion criteria. We used the evidence levels recommended by the Oxford Centre for Evidence-Based Medicine to assess bias. The R version 4.2.3 software was utilized to calculate the mean effect size. We estimated study heterogeneity by employing tau2 and I2 indices and conducting Cochran's Q test.

Results

The results showed that DBS treatment resulted in a significant improvement in the clinical SUD scales of patients, with an average improvement of 59.6%. The observed relapse rate was 8%. The meta-analysis estimated a mean effect size of 55.9 [40.4; 71.4]. Heterogeneity analysis showed a large degree of heterogeneity among the included studies. Subgroup and meta-regression analysis based on age and SUD type suggested that DBS may be more effective for patients above 45 years of age, and for alcohol and opioid addiction compared to nicotine addiction.

Conclusion

The current literature suggests that DBS has a moderate effect on SUD symptoms. However, the limited number of studies and small sample size indicate that more research is needed to better understand the factors that influence its effectiveness.

Neuroimaging of Deep Brain Stimulation

Deep brain stimulation is the most advanced and effective neuromodulation therapy for Parkinson disease, essential tremor, and generalized dystonia. This article discusses how imaging improves surgical techniques and outcomes and widens possibilities in translational neuroscience in Parkinson disease, essential tremor, generalized dystonia, and epilepsy. In movement disorders diffusion tensor imaging allows anatomic segment of cortical areas and different functional subregions within deep-seated targets to understand the side effects of stimulation and gain more data to describe the therapeutic mechanism of action. The introduction of visualization of white matter tracks increases the safety of neurosurgical techniques in functional neurosurgery and neuro-oncology.

Deep brain stimulation for the treatment of drug addiction

Drug addiction represents a significant public health concern that has high rates of relapse despite optimal medical therapy and rehabilitation support. New therapies are needed, and deep brain stimulation (DBS) may be an effective treatment. The past 15 years have seen numerous animal DBS studies for addiction to various drugs of abuse, with most reporting decreases in drug-seeking behavior with stimulation. The most common target for stimulation has been the nucleus accumbens, a key structure in the mesolimbic reward pathway. In addiction, the mesolimbic reward pathway undergoes a series of neuroplastic changes. Chief among them is a relative hypofunctioning of the prefrontal cortex, which is thought to lead to the diminished impulse control that is characteristic of drug addiction. The prefrontal cortex, as well as other targets involved in drug addiction such as the lateral habenula, hypothalamus, insula, and subthalamic nucleus have also been stimulated in animals, with encouraging results. Although animal studies have largely shown promising results, current DBS studies for drug addiction primarily use stimulation during active drug use. More data are needed on the effect of DBS during withdrawal in preventing future relapse. The published human experience for DBS for drug addiction is currently limited to several promising case series or case reports that are not controlled. Further animal and human work is needed to determine what role DBS can play in the treatment of drug addiction.

Emerging Issues Task Force, International Neuroethics Society. Neuroethics at 15: The Current and Future Environment for Neuroethics

Neuroethics research and scholarship intersect with dynamic academic disciplines in science, engineering, and the humanities. On the occasion of the 15th anniversary of the formation of the International Neuroethics Society, we identify current and future topics for neuroethics and discuss the many social and political challenges that emerge from the converging dynamics of neurotechnologies and artificial intelligence. We also highlight the need for a global, transdisciplinary, and integrated community of researchers to address the challenges that are precipitated by this rapid sociotechnological transformation.

The early argument for prefrontal leucotomy: the collision of frontal lobe theory and psychosurgery at the 1935 International Neurological Congress in London

The pathophysiology of mental illness and its relationship to the frontal lobe were subjects of immense interest in the latter half of the 19th century. Numerous studies emerged during this time on cortical localization and frontal lobe theory, drawing upon various ideas from neurology and psychiatry. Reflecting the intense interest in this region of the brain, the 1935 International Neurological Congress in London hosted a special session on the frontal lobe. Among other presentations, Yale physiologists John Fulton and Carlyle Jacobsen presented a study on frontal lobectomy in primates, and neurologist Richard Brickner presented a case of frontal ablation for olfactory meningioma performed by the Johns Hopkins neurosurgeon Walter Dandy. Both occurrences are said to have influenced Portuguese neurologist Egas Moniz (1874-1955) to commence performing leucotomies on patients beginning in late 1935. Here the authors review the relevant events related to frontal lobe theory leading up to the 1935 Neurological Congress as well as the extent of this meeting's role in the genesis of the modern era of psychosurgery.

Deep brain stimulation for psychiatric disorders: where we are now

Fossil records showing trephination in the Stone Age provide evidence that humans have sought to influence the mind through physical means since before the historical record. Attempts to treat psychiatric disease via neurosurgical means in the 20th century provided some intriguing initial results. However, the indiscriminate application of these treatments, lack of rigorous evaluation of the results, and the side effects of ablative, irreversible procedures resulted in a backlash against brain surgery for psychiatric disorders that continues to this day. With the advent of psychotropic medications, interest in invasive procedures for organic brain disease waned.

Diagnosis and classification of psychiatric diseases has improved, due to a better understanding of psychiatric patho-physiology and the development of disease and treatment biomarkers. Meanwhile, a significant percentage of patients remain refractory to multiple modes of treatment, and psychiatric disease remains the number one cause of disability in the world. These data, along with the safe and efficacious application of deep brain stimulation (DBS) for movement disorders, in principle a reversible process, is rekindling interest in the surgical treatment of psychiatric disorders with stimulation of deep brain sites involved in emotional and behavioral circuitry.

This review presents a brief history of psychosurgery and summarizes the development of DBS for psychiatric disease, reviewing the available evidence for the current application of DBS for disorders of the mind.

Spinal cord injury after blunt cervical spine trauma: correlation of soft-tissue damage and extension of lesion

BACKGROUND AND PURPOSE

In patients with spinal cord injury after blunt trauma, several studies have observed a correlation between neurologic impairment and radiologic findings. Few studies have been performed to correlate spinal cord injury with ligamentous injury. The purpose of this study was to retrospectively evaluate whether ligamentous injury or disk disruption after spinal cord injury correlates with lesion length.

MATERIALS AND METHODS

We retrospectively reviewed 108 patients diagnosed with traumatic spinal cord injury after cervical trauma between 1990-2011. Plain films, CT, and MR imaging were performed on patients and then reviewed for this study. MR imaging was performed within 96 hours after cervical trauma for all patients. Data regarding ligamentous injury, disk injury, and the extent of the spinal cord injury were collected from an adequate number of MR images. We evaluated anterior longitudinal ligaments, posterior longitudinal ligaments, and the ligamentum flavum. Length of lesion, disk disruption, and ligamentous injury association, as well as the extent of the spinal cord injury were statistically assessed by means of univariate analysis, with the use of nonparametric tests and multivariate analysis along with linear regression.

RESULTS

There were significant differences in lesion length on T2-weighted images for anterior longitudinal ligaments, posterior longitudinal ligaments, and ligamentum flavum in the univariate analysis; however, when this was adjusted by age, level of injury, sex, and disruption of the soft tissue evaluated (disk, anterior longitudinal ligaments, posterior longitudinal ligaments, and ligamentum flavum) in a multivariable analysis, only ligamentum flavum showed a statistically significant association with lesion length. Furthermore, the number of ligaments affected had a positive correlation with the extension of the lesion.

CONCLUSIONS

In cervical spine trauma, a specific pattern of ligamentous injury correlates with the length of the spinal cord lesion in MR imaging studies. Ligamentous injury detected by MR imaging is not a dynamic finding; thus it proved to be useful in predicting neurologic outcome in patients for whom the MR imaging examination was delayed.

Neuromodulation for obsessive-compulsive disorder

This article describes the basis for neuromodulation procedures for obsessive-compulsive disorder (OCD) and summarizes the literature on the efficacy of these interventions. Discussion includes neural circuitry underlying OCD pathology, the history and types of ablative procedures, the targets and modalities used for neuromodulation, and future therapeutic directions.

The contemporary practice of psychiatric surgery: results from a global survey of functional neurosurgeons

BACKGROUND

Interest in neurosurgery for psychiatric diseases (NPD) has grown globally. We previously reported the results of a survey of North American functional neurosurgeons that evaluated general attitudes towards NPD and the future directions of the field.

OBJECTIVES

The purpose of this study was to expand on our previous work and obtain a snapshot in time of global attitudes towards NPD among practicing functional neurosurgeons. We measure general and regional trends in functional neurosurgery and focus specifically on surgery for mind and mood, while exploring the future prospects of the field.

METHODS

We designed an online survey and distributed it electronically to 881 members of the following international organizations: World Society for Stereotactic and Functional Neurosurgery, European Society for Stereotactic and Functional Neurosurgery, Asian-Australasian Society for Stereotactic Functional Neurosurgery and the South and Latin American Society for Stereotactic and Functional Neurosurgery. Subsequent statistical and thematic analysis was performed on the data obtained.

RESULTS

Of 881 surveys distributed, 106 were returned (12.8%). Eighty-two percent of functional neurosurgeon respondents were fellowship trained, with movement disorders and pain making up the majority of their practice. Psychiatric indications are the most frequently treated conditions for 34% of survey respondents, and over half of participants (51%) perform epilepsy surgery. Of the psychiatric conditions, obsessive-compulsive disorder and depression are the most common disorders treated. The majority of respondents (90%) felt optimistic about the future of NPD. Two thirds cited the reluctance of psychiatrists to refer patients as the greatest obstacle facing the field, and a majority reported that a cultural stigma surrounding psychiatric diseases exists in their community. In response to hypothetical situations involving cognitive and personality enhancement, opinions varied, but the majority opposed enhancement interventions. Regional variations were examined as well and uncovered distinct attitudinal differences depending on geographic location.

CONCLUSIONS

Surgery for psychiatric conditions is an expanding field within functional neurosurgery. The opinions of international functional neurosurgeons were largely in line with those of their North American colleagues. Optimism regarding the future of NPD predominates, and future editions of this survey can be used to track the evolution of neurosurgeons' attitudes towards NPD and neuroenhancement.

Deep brain stimulation of the nucleus accumbens for the treatment of addiction

Despite novel medications and other therapeutic strategies, addiction to psychotropic substances remains one of the most serious public health problems worldwide. In this review, beginning with an introduction of deep brain stimulation (DBS), we highlight the importance of the nucleus accumbens (NAc) in the context of the reward circuitry and addictive behavior. We will provide a short historic overview of other neurosurgical approaches to treat addiction and describe the experimental and preclinical data on DBS in addiction. Finally, we call attention to key ethical issues related to using DBS to treat addiction that are important for future research and the design of clinical trials.

Potential utility of optogenetics in the study of depression

Novel antidepressants are needed to enhance the health and quality of life of the hundreds of millions of depressed individuals worldwide who remain inadequately treated with today's approaches. In reality, no new class of antidepressant medication has been introduced in over 50 years. This insufficiency of current drug treatments is evident to those eager to pursue invasive experimental options like that of deep brain stimulation. Encouragingly, human brain imaging studies and animal work implicate strong relationships between depressive symptoms and patterns of brain activity, which are now open to more empirical assessments using optogenetics. Recent advances in optogenetics permit control over specific subtypes of neurons or their afferent or efferent projections and can greatly further our understanding of the neural mechanisms involved in depression and the mechanism of action of deep brain stimulation and perhaps chemical antidepressants. Here, we discuss how optogenetic tools are being used to answer a broad range of molecular, cellular, and circuit-level questions pertaining to depression that, up until now, have been resistant to other experimental approaches. The emergence of optogenetic technology, when combined with the best-validated animal models of depression, will dramatically increase knowledge about the basic neurobiology of depression, as well as facilitate the development of more effective antidepressant treatments.

[Egas Moniz: a genius, unlucky looser or a Nobel committee error?]

Portuguese neurologist António Egas Moniz is one of the most intriguing figures in the history of medicine. While an invention of angiography in 1927 is his acknowledged merit, lobotomy, invented in 1935 became a black legend of psychiatry, although sporadically it is performed also today. There are even postulates to withdraw the Nobel Prize, which Moniz received in 1949 for inventing the lobotomy. Moniz in fact re-invented lobotomy, primarily introduced in 1888 by a Swiss psychiatrist Gottlieb Burckhardt and later forgotten. Its popularisation, including its abuses was chiefly done by American neurologists Walter Freeman and James Watts. Aside the science, Moniz was an exceptionally colourful person, a merited politician, Portuguese minister of foreign affairs, the head of its delegation at Versailles in 1918, in 1951 he was even proposed a position of a President of Portugal. He was a versatile humanist and a writer, even a gambling expert. His person is hard for black and white evaluation, definitely deserving a re-evaluation from today's historical perspective.

Novel applications of deep brain stimulation

The success of deep brain stimulation (DBS) surgery in treating medically refractory symptoms of some movement disorders has inspired further investigation into a wide variety of other treatment-resistant conditions. These range from disorders of gait, mood, and memory to problems as diverse as obesity, consciousness, and addiction. We review the emerging indications, rationale, and outcomes for some of the most promising new applications of DBS in the treatment of postural instability associated with Parkinson's disease, depression, obsessive–compulsive disorder, obesity, substance abuse, epilepsy, Alzheimer′s-type dementia, and traumatic brain injury. These studies reveal some of the excitement in a field at the edge of a rapidly expanding frontier. Much work still remains to be done on basic mechanism of DBS, optimal target and patient selection, and long-term durability of this technology in treating new indications.

Participants' Perceptions of Deep Brain Stimulation Research for Treatment-Resistant Depression: Risks, Benefits, and Therapeutic Misconception

BACKGROUND

Deep brain stimulation (DBS) for treatment-resistant depression (TRD) is the focus of great interest and numerous studies. Given the state of this research, the risks of DBS, the uncertainty of direct benefits, and the potential for therapeutic misconception (TM), examination of research participants' perspectives is critical to addressing concerns about the adequacy of consent among people with TRD.

METHODS

Among 31 participants considering DBS studies at two sites, self-report questionnaires were used to examine three dimensions of TM (eight true/false items). Additional Likert-scale items assessed perceptions of risks, potential benefits, and altruistic motivations.

RESULTS

Participants correctly identified the surgery itself as the riskiest study procedure, although only four participants rated the surgery as "high risk." Most participants rated the entire DBS study as "moderate" or lower risk. Participants rated the likelihood of others benefiting in the future more strongly than they did the likelihood of personal benefit. Participants held positive attitudes toward research, and were moderately altruistic. Nearly two-thirds of the 31 participants (64.5%) answered at least one of the true/false TM items incorrectly.

CONCLUSIONS

Individuals considering DBS studies for TRD demonstrated reasonable perceptions of risks and benefits, distinguished among procedural risks, and expressed hopes for personal benefit as well as altruism. Findings related to TM were mixed: Participants understood the experimental stage of DBS for depression and endorsed the possibility of no personal benefit, yet there was some evidence for TM. Although these findings are reassuring, investigators must nevertheless remain vigilant about identifying and addressing potential misconceptions.