Awake mapping may add a patient-specific layer to DBS planning
Deep brain stimulation is often described in terms of its hardware: thin implanted leads that deliver electrical impulses to carefully selected areas of the brain. But a Mayo Clinic study argues that the most useful information for placing those leads may not always be visible on a scan alone.
The retrospective study, published in Operative Neurosurgery, examined awake deep brain stimulation procedures for patients with essential tremor. Its central finding is not that imaging lacks value. Imaging remains the foundation for planning where a lead should go. Instead, the researchers found that brain recordings, stimulation testing and direct patient feedback collected during surgery can provide additional information that changes the final placement of a lead.
That distinction matters because DBS is used to alter abnormal brain activity in conditions including essential tremor, Parkinson’s disease and dystonia. The therapy depends on positioning electrodes in locations where stimulation can suppress symptoms while avoiding unwanted effects. A standard target derived from imaging can work well for many people, but the Mayo team says the best position can vary slightly from one patient to another.
What awake DBS adds during a procedure
During an awake procedure, clinicians can measure brain activity, test stimulation and ask the patient about the effects in real time. If recordings or stimulation testing suggest that the planned position is not ideal, the surgical team can adjust the lead’s placement before the operation is complete.
That creates an interactive process that differs from DBS performed while the patient is asleep. In the asleep approach described by the researchers, clinicians rely primarily on imaging to guide positioning. Awake surgery can add physiological measurements and observed clinical responses to that imaging-based plan.
The study focused on essential tremor, a disorder marked by involuntary shaking. The source material does not present awake DBS as a replacement for imaging or as a universal requirement. Rather, it frames awake mapping as a way to personalize treatment when a fixed image-based target may not fully capture the position that produces the best balance of tremor control and side effects for an individual patient.
What the researchers examined
Mayo Clinic researchers reviewed 137 DBS leads implanted while patients were awake during surgery for essential tremor. For each lead, the team considered whether the final implant followed the originally planned path, required a change in depth, or was moved to a parallel trajectory after brain-activity recordings and stimulation testing.
The researchers also compared tremor suppression and side effects before and after leads were repositioned. That design addresses a practical question: when an intraoperative adjustment is made, is it simply a variation that could have been predicted by imaging, or does awake testing reveal useful information that imaging alone does not provide?
According to the report, about 15% of the leads in the review involved information gathered during surgery that changed final positioning. Even without broader outcome figures in the supplied report, that proportion illustrates why the team sees awake mapping as more than a procedural formality. In a subset of cases, it influenced where the permanent lead was ultimately implanted.
Why placement remains central
DBS does not operate in a vacuum. A lead’s relationship to surrounding brain structures affects both its therapeutic potential and the possibility of stimulation-related side effects. Imaging can supply an anatomical map and a planned route, but anatomy alone may not show every functional difference relevant to a particular patient’s response.
Awake mapping is intended to narrow that gap. Neurophysiological recordings can provide signals from the brain, while stimulation testing lets the team observe whether a proposed location improves tremor and whether it produces effects that make the position less desirable. The patient’s feedback becomes part of the placement decision rather than information collected only after recovery.
For clinicians, the implication is measured but important: a procedure planned around a standard target can retain room for adjustment when direct evidence indicates that an alternative position may be better. For patients, the potential value is a treatment plan that is tailored not only to a brain image but also to the response observed during the operation.
A study of surgical decision-making
The Mayo analysis is retrospective, meaning it reviews procedures that have already taken place. It should therefore be read as evidence about how often intraoperative information affected decisions in this group of awake essential-tremor cases, rather than as a definitive comparison of all awake and asleep DBS approaches.
Still, the work highlights a broader issue in neuromodulation: precision is not only a matter of selecting a target on a scan. It can also involve testing whether that target is delivering the intended clinical effect in the person on the operating table.
As DBS techniques and planning tools continue to develop, the study offers a clear rationale for preserving a role for direct functional assessment. Imaging can establish the plan; awake mapping may help determine whether the plan is the best final answer for a specific patient.
This article is based on reporting by Medical Xpress. Read the original article.
Originally published on medicalxpress.com
