Wednesday, September 9, 2015

Uncertain Health in an Insecure World – 55

“Distributive Justice”

In this, the emerging era of precision medicine, while much is promised to many, often less is delivered to a privileged few. Distributive justice apportions privileges and goods in consonance with the merits of the individual and the best interests of society. 

For decades, neuroscientists have known that different sensory, motor, reflexive and cognitive functions home in the deep and superficial brain. A miniature human, the Homunculus, first described in 1656 (above, left), represents neuro-cortical functions along the sensori-motor brain strip (above, right). Such precise localization (confirmed by functional magnetic resonance imaging, below) gives neurologists and neurosurgeons therapeutic targets. The excision of an arterio-venous malformation can cure epilepsy. The radio-ablation of a tumor can restore eyesight.

Nowhere else in the body can doctors successfully play such high stakes medical whack-a-mole.

In a 2013 TED talk, University of Toronto neurosurgeon Andres Lozano (above) described deep brain stimulation (DBS) on conscious patients. During what’s called functional neurosurgery, precisely placed probes carry minute doses of electrical impulse to carefully characterized deep brain sites. In his talk, Lozano described one patient’s sensation of the weight of chronic depression being suddenly lifted from his chest by a brief jolt to Brodmann area 25 (subgenual cingulate Cg25, below) in the medial forebrain (a.k.a. the ‘human rewards system’). With a little more juice to this area, the same patient reported seeing himself walking in a sunny field with a former girlfriend, feeling the echoed joy of moments some thirty years earlier.

Each time the electron flow stopped, the good vibrations ebbed.

DBS for depression, initiated in 2005 by Lozano and Emory neurologist Helen Mayberg (above), was widely reported and highly touted as a breakthrough in the treatment of intractable depression. This concept aligned well with the NIH Brain Initiative, the neuro-science moonshot announced by President Obama in 2013 (below). That year, NIH National Institute of Mental Health Director Tom Insel blogged, “… if mental disorders are brain circuit disorders, then successful treatments need to tune circuits with precision. Chemicals (drugs) may be less precise than electrical or cognitive interventions that target specific circuits.

But in January 2014, the BROADEN clinical trial of this approach (sponsored by St. Jude Medical Inc.) was suspended by the FDA due to unexpectedly poor results. Separate reports of the surgical risks of this costly procedure (i.e., cerebral hemorrhage) and of psychiatric complications (i.e., suicide risk, hypomania) have emerged.

After a long decade, the jury is still out on the efficacy and safely of DBS for treatment-resistent depression (TRD).

Cosmetic neurosurgery is a term loosely describing the potential of such expensive functional procedures to 'fix' unsightly but non-lethal tremors or tics. Akin to a plastic surgery chin implant or breast augmentation, could the placement of a deep brain probe do more than improve the bodily dysfunction of dystonia or Parkinson’s disease? Could it also lift sad moods, and literally lighten the psychological burden of TRD patients?

What could possibly be wrong with doctors using all this newly re-imagined high technology?

As Dr. Lozano pointed out in a recent TED Radio interview, limiting access to medical care by wealth or societal position creates a potential distributive justice problem. This issue sits in the core of ethical concerns about medical tourism – the wealthy shopping the world for transplant organs or more timely elective cardiac surgery. Assuming someone had accumulated a fortune before entering a deep, chronic depression, that person could potentially pay for a rapid DBS return to full functioning, if only for a time. 
Such market-driven access to precision medical miracles and cures is patently unjust.

In the Square, in the painless recesses of our brains, we are saddened by the slow pace of progress and uneven distribution of results.

It’s depressing, but of course, there’s a device for that!

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