Having More Comorbidities Linked with Confusion After DBS in Parkinson’s Patients

Having a higher number of comorbidities is associated with postoperative confusion in Parkinson’s patients undergoing deep brain stimulation (DBS), according to a new study in Brazilian patients.

The study, “Postoperative Confusion in Patients with Parkinson’s Disease Undergoing Deep Brain Stimulation of the Subthalamic Nucleus,” appeared in the journal World Neurosurgery.

DBS targeting the subthalamic nucleus (STN) — a brain region hyperactive in Parkinson’s patients and implicated in motor control — has been shown to ease motor symptoms, but it may be associated with side effects such as postoperative confusion. This complication may damage the surgical hardware due to agitation and require treatment with antipsychotics, many of which are contraindicated in Parkinson’s.

Postoperative confusion has been correlated with imaging and clinical factors, such as older age and longer disease duration. However, no studies explored its incidence and associated factors in Brazilian patients with Parkinson’s undergoing DBS of the STN.

Aiming to address this, researchers conducted a retrospective chart review of 49 patients (33 men, mean age 57.5 years) undergoing this procedure from January 2013 to October 2017 at Hospital de Clínicas de Porto Alegre, in Brazil. Patients with dementia, severe/untreated neuropsychiatric disorders, or spontaneous or antiparkinsonian medication-induced psychosis were excluded. All surgeries were performed under local anesthesia.

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Among the analyzed imaging factors were brain atrophy, or shrinkage; lesions in the white matter — made of nerve fibers — intracranial hemorrhage after surgery, and ventricular wall transgression (breaching the walls of the brain’s ventricles, a network of interconnected cavities). Clinical factors evaluated included gender, history of depression and hallucinations, age, disease duration, comorbidities — the presence of one or more additional diseases or disorders co-occurring with Parkinson’s — length of hospital stay, and duration of surgery.

Confusion was defined as any degree of disorientation and attention and/or perception impairment, associated with cognitive dysfunction and with a sudden beginning and short duration, from the first postoperative hours until hospital discharge.

The results showed that the incidence of postoperative confusion was 26.5% (13 patients), which was higher than in prior studies, researchers noted. This may have been due to the small number of patients in their study and to technical differences in DBS, they suggested.

In comparison to patients not developing confusion, those with confusion were older (mean age 63.2 vs. 55.4 years), had longer disease duration (16.5 vs. 13.2 years), higher comorbidities, longer hospital stays after surgery and a greater width of the third ventricle, one of the four brain ventricles.

There was a trend toward more intracranial hemorrhage in patients who developed confusion, as assessed with computed tomography, although not statistically significant. No patient needed re-intervention or prolonged sedation.

A subsequent statistical analysis accounting for potential confounding factors revealed that only the association with comorbidities remained significant. The team commented that “it is well-recognized that the presence of various comorbidities is a risk factor for postoperative delirium.”

The investigators said that studies with larger groups of patients are needed to identify which variables are more relevant in the development of confusion in Parkinson’s patients undergoing this surgery.