Alienation and Authenticity in Parkinson's Disease and Its Treatment

Why are some patients with Parkinson’s disease unhappy about the outcome of deep brain stimulation (DBS)? Meccaci and Haselager (2014) attempt to answer this question by analyzing the seminal case series of Schupbach and colleagues (2006) that documented postoperative difficulties with personal and social adjustment in patients with Parkinson’s disease (PD) who had been treated with DBS of the subthalamic nucleus (STN). This paper foreshadowed a growing recognition of the difficulties experienced by a minority of patients who, despite effective reduction of their motor symptoms, experience a reduction in their quality of life. These challenges are not unique to DBS. Any rehabilitative procedure may affect cognitive, psychological, and social functioning, necessitating adaptation by patients to their social support network and the effects of the intervention. Among the many factors that affect this process are baseline levels of functional disability, social resources, comorbid mood disorder, and cognitive impairment (Mosley and Lyness 2014). Patients with implanted devices may face the additional challenge of incorporating this intervention into their self-schema, whether it be a neural stimulator, pacemaker, or colostomy bag. Meccaci and Haselager imply that there is something special about DBS. They argue that neuromodulation challenges the folk dualism of DBS patients (that they are autonomous and authentic agents), creating existential angst. They hypothesize that “thoughts about being stimulated” are encouraged by clinicians who present their patients with a “neuroessentialist” or “neurocentric” paradigm that reduces self to brain function. They argue that if neurologists instead used a nonreductionist account of mind–body relationships, such as “embodied embedded cognition,” then some of these postoperative difficulties might be prevented. Their article makes assumptions, only some of which are acknowledged. First, the authors provide no evidence that neurologists hold neuroessentialist views of the self, let alone communicate these to their patients. Recognition that DBS can affect motor function and cognition, or have potentially adverse effects on movement, thought, or behavior, does not entail essentialism. Indeed, if DBS did not affect these processes, there would be little justification in performing it. Second, there is also no evidence presented that patients embrace dualism in understanding DBS. Our experience at the Asia-Pacific Centre for Neuromodulation in Australia, which has performed over 700 DBS procedures, is that patients are more sophisticated than the authors believe. Although the “risk of becoming another person” has been discussed among neuroscientists and philosophers (Mathews, Bok, and Rabins 2009), in our experience, it is not a prospect that causes concern among patients. Third, their argument that DBS uniquely undermines the self simplifies the multiplicity of components that can cause personal difficulties for those who undergo DBS for PD. A unique feature of the DBS device is its ability to modify mood, decision making, and behavior in a stimulation-dependent fashion (Mosley and Marsh in press). The postoperative course can be complicated by mania, impulsivity, and compulsive disorders such as pathological gambling or hypersexuality. These symptoms can alienate loved ones and prevent successful adaptation post-DBS. Adjusting the stimulation parameters can often reverse these adverse effects. But the situation is often more complex than this. DBS for PD challenges a fragile homeostatic system that has already been modified by years of neurodegeneration and daily dopaminergic medication. Depression, anxiety, and apathy may arise postoperatively as a result of the withdrawal of dopaminergic medication, or in response to the progression of nonmotor aspects of the disease. Patients who struggle to “find themselves” after the operation often respond to repletion of dopamine (Lhommee et al. 2012). Carer burden is also substantially