Longitudinal Neuropsychological Assessment of Symptomatic Edema after Subthalamic Nucleus Deep Brain Stimulation Surgery: A Case Series Study.

Severe non-infectious or non-haemorrhagic brain edema surrounding the electrode represents a rare complication of subthalamic nucleus deep brain stimulation (STN-DBS) surgery. The aim of this study is to report three patients with advanced Parkinson's Disease (PD) who developed symptomatic brain edema after STN-DBS surgery treated with intravenous steroids with a specific profile of reversible cognitive alterations. Patients were both assessed with a comprehensive neuropsychological battery including attention, memory, visuo-spatial and executive tasks. They were also briefly assessed for emotional and behavioural alterations, and for possible limitations in the activities of daily living. Normative data for an Italian population were available for all neuropsychological tests. The patients were firstly assessed before the surgery (baseline) as soon as they became symptomatic for the post-surgery edema and a few more times in follow-up up to ten months. In all patients we observed the resolution of cognitive deficits within six months after surgery with the corresponding reabsorption of edema at brain CT scans. The appearance of post-DBS edema is a fairly frequent and clinically benign event. However, in some rare cases it can be very marked and lead to important clinical-albeit transient-disturbances. These events can compromise, at least from a psychological point of view, the delicate path of patients who undergo DBS and can prolong the post-operative hospital stay. In this setting it could be helpful to perform a brain CT scan in 2-3 days with the aim of detecting the early appearance of edema and treating it before it can constitute a relevant clinical problem.

Should we screen for cognitive decline and dementia?

Due to increased life expectancy, the prevalence of cognitive decline related to neurodegenerative diseases and to non-neurological conditions is increasing in western countries. As with other diseases, the burden might be reduced through personalized interventions delivered at early stages of the disease. Thus, there is an increasing demand, from both social and healthcare systems, for instruments and strategies to recognize cognitive decline, and possibly distinguish the precursor of serious neurodegeneration from "benign senile forgetfulness" or the temporary consequences of illness or trauma. However, this goal faces both technical and ethical issues. In this article we deal with the following: (i) re-definition of cognitive decline and its relationship with frailty definitions, starting from the recent work of international consensus groups for presymptomatic Alzheimer disease recognition; (ii) ethical problems concerning anonymous and personalized cognitive screening and the need for appropriate counselling; (iii) the need for more sensitive and specific tools to detect and distinguish pathological levels of cognitive decline and delineate the contribution of non-pathological decline to accumulated frailty impacts and (iv) the potential of the language domain and spontaneous speech analyses.