Deep Brain Stimulation for the Treatment of Alzheimer Disease and Dementias.

Division of Neurosurgery, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada.
World Neurosurgery (Impact Factor: 1.77). 06/2012; DOI: 10.1016/j.wneu.2012.06.028
Source: PubMed

ABSTRACT OBJECTIVE: To review the use of deep brain stimulation (DBS) for treatment of dementia. METHODS: A PubMed literature search was conducted to identify all studies that have investigated the use of DBS for treatment of dementia. RESULTS: Three studies examined the use of DBS for dementia. One study involved fornix DBS for Alzheimer disease (AD), and two studies involved DBS of the nucleus basalis of Meynert, one to treat AD and one to treat Parkinson disease dementia. CONCLUSUIONS: Evidence for the use of DBS to treat dementia is preliminary and limited. Fornix and nucleus basalis of Meynert DBS can influence activity in the pathologic neural circuits that underlie AD and Parkinson disease dementia. Further investigation into the potential clinical effects of DBS for dementia is warranted.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In the last quarter of a century, DBS has become an established neurosurgical treatment for Parkinson's disease (PD), dystonia, and tremors. Improved understanding of brain circuitries and their involvement in various neurological and psychiatric illnesses, coupled with the safety of DBS and its exquisite role as a tool for ethical study of the human brain, have unlocked new opportunities for this technology, both for future therapies and in research. Serendipitous discoveries and advances in structural and functional imaging are providing abundant "new" brain targets for an ever-increasing number of pathologies, leading to investigations of DBS in diverse neurological, psychiatric, behavioral, and cognitive conditions. Trials and "proof of concept" studies of DBS are underway in pain, epilepsy, tinnitus, OCD, depression, and Gilles de la Tourette syndrome, as well as in eating disorders, addiction, cognitive decline, consciousness, and autonomic states. In parallel, ongoing technological development will provide pulse generators with longer battery longevity, segmental electrode designs allowing a current steering, and the possibility to deliver "on-demand" stimulation based on closed-loop concepts. The future of brain stimulation is certainly promising, especially for movement disorders-that will remain the main indication for DBS for the foreseeable future-and probably for some psychiatric disorders. However, brain stimulation as a technique may be at risk of gliding down a slippery slope: Some reports indicate a disturbing trend with suggestions that future DBS may be proposed for enhancement of memory in healthy people, or as a tool for "treatment" of "antisocial behavior" and for improving "morality." © 2013 International Parkinson and Movement Disorder Society.
    Movement Disorders 10/2013; · 5.63 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Major depressive disorder is a worldwide disease with debilitating effects on a patient's life. Common treatments include pharmacotherapy, psychotherapy, and electroconvulsive therapy. Many patients do not respond to these treatments; this has led to the investigation of alternative therapeutic modalities. Deep brain stimulation (DBS) is one of these modalities. It was first used with success for treating movement disorders and has since been extended to the treatment of psychiatric disorders. Although DBS is still an emerging treatment, promising efficacy and safety have been demonstrated in preliminary trials in patients with treatment-resistant depression (TRD). Further, neuroimaging has played a pivotal role in identifying some DBS targets and remains an important tool for evaluating the mechanism of action of this novel intervention. Preclinical animal studies have broadened knowledge about the possible mechanisms of action of DBS for TRD, Given that DBS involves neurosurgery in patients with severe psychiatric impairment, ethical questions concerning capacity to consent arise; these issues must continue to be carefully considered.
    Dialogues in clinical neuroscience. 03/2014; 16(1):83-91.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Entropy is a dimensionless quantity that is used for measuring uncertainty about the state of a system but it can also imply physical qualities, where high entropy is synonymous with high disorder. Entropy is applied here in the context of states of consciousness and their associated neurodynamics, with a particular focus on the psychedelic state. The psychedelic state is considered an exemplar of a primitive or primary state of consciousness that preceded the development of modern, adult, human, normal waking consciousness. Based on neuroimaging data with psilocybin, a classic psychedelic drug, it is argued that the defining feature of "primary states" is elevated entropy in certain aspects of brain function, such as the repertoire of functional connectivity motifs that form and fragment across time. Indeed, since there is a greater repertoire of connectivity motifs in the psychedelic state than in normal waking consciousness, this implies that primary states may exhibit "criticality," i.e., the property of being poised at a "critical" point in a transition zone between order and disorder where certain phenomena such as power-law scaling appear. Moreover, if primary states are critical, then this suggests that entropy is suppressed in normal waking consciousness, meaning that the brain operates just below criticality. It is argued that this entropy suppression furnishes normal waking consciousness with a constrained quality and associated metacognitive functions, including reality-testing and self-awareness. It is also proposed that entry into primary states depends on a collapse of the normally highly organized activity within the default-mode network (DMN) and a decoupling between the DMN and the medial temporal lobes (which are normally significantly coupled). These hypotheses can be tested by examining brain activity and associated cognition in other candidate primary states such as rapid eye movement (REM) sleep and early psychosis and comparing these with non-primary states such as normal waking consciousness and the anaesthetized state.
    Frontiers in Human Neuroscience 01/2014; 8:20. · 2.91 Impact Factor


Available from
Aug 1, 2014