Professional Blog

Microelectrode Recordings: How Much is Enough?

Microelectrode Recordings (MERs) It would appear obvious that there is a great diversity in surgical approaches to Deep Brain Stimulation (DBS) lead implantation. In the near mathematical impossibility of randomized control trials that pits each different approach against the others, how is one to decide which approach or method is best? These newsletters have arg...

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Local Field Potentials: What Do They Mean?

The drunkard looking for his wallet that he lost up the road was asked why look beneath the street lamp.  He replied, “The light is better.” Local Field Potentials (LFPs) have gotten a great deal of press in the literature related to the pathophysiology of Parkinson’s disease and to Deep Brain Stimulation (DBS).  For example, increased amounts (power) of oscilla...

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Rechargeable Implanted Pulse Generators and Directional Leads for DBS: An Exercise in Ethics

Resident:  Regarding the use of non-rechargeable implanted pulse generators and directionally steerable leads, isn’t the situation one of “penny wise, pound (English equivalent of the dollar) foolish”? Attending:  That depends on who is spending the penny and who is spending the pound. Clinicians now have choices in the type of implanted pulse generator (IPG)...

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Caution Advised: Deep Brain Stimulation (DBS) is Not Normal and Does Not Restore Normality

Professor:  As Abraham Maslow said, “when all you have is a hammer, the whole world looks like a nail.” Student:  The statement presupposes that one knows that something other than a hammer exists even if it is not available.  It would not make sense if only “hammers” existed because there would be nothing to differentiate “hammer” from anything else.  Indeed, t...

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A Chain is Only as Strong as its Weakest Link: the Microelectrode

The targets for Deep Brain Stimulation (DBS) for movement disorders are not the subthalamic nucleus (STN), globus pallidus interna (GPi) or the ventral intermediate nucleus of the thalamus (Vim).  It is the sensori-motor region of the STN.  It is the motor homunculus appropriate to the patient’s symptomology in the GPi and Vim.  To date, the only way to confidentia...

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Risk Involved in Advancing Microelectrodes with Tips Withdrawn

We recently learned that some intraoperative neurophysiologists and neurosurgeons utilize the large indifferent or reference electrical contact for macrostimulation during targeting of the Deep Brain Stimulation (DBS) lead. Such macrostimulation may be useful to infer the regional anatomy and physiology of the electrode location and to, perhaps, anticipate post-ope...

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Is it a Sin if One Does Not Get Caught?

Person A – If you use this method you can double the risk of problems. Person B – We rarely have problems.  Person A – How would you know? And you still are doubling the risk. Fortunately, the major risks associated with Deep Brain Stimulation lead implantation surgery are relatively rare. For example, while post-operative scanning may reveal an intracere...

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A Calling to be Better than Ourselves

Dear Dr. Montgomery: I did not refer the patient [to you]. I don’t need your help. Here is your evaluation and recommendations back. Dr. X The patient sought a second opinion, as is any patients’ right. The patient asked that the evaluation and recommendations be sent to Dr. X, which any physician so asked would be obligated to do. The paradox is that Dr. ...

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Preoperative Neuropsychological Testing for Deep Brain Stimulation: The Right Action Perhaps for the Wrong Reason

Many, if not most centers implanting Deep Brain Stimulation (DBS) leads conduct neuropsychological testing prior to surgery. The reasonable question is why? Perhaps it is because neuropsychological testing was used in Randomized Control Trials (RCTs) of DBS. However, just importing inclusion/exclusion criteria from RCTs into general practice is problematic and ofte...

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