The network is more important than the node: stereo-EEG evidence of neurocognitive networks in epilepsy.

Introduction: Neuropsychological assessment forms an integral part of the presurgical evaluation for patients with medically refractory focal epilepsy. Our understanding of cognitive impairment in epilepsy is based on seminal lesional studies that have demonstrated important structure-function relationships within the brain. However, a growing body of literature demonstrating heterogeneity in the cognitive profiles of patients with focal epilepsy (e.g., temporal lobe epilepsy; TLE) has led researchers to speculate that cognition may be impacted by regions outside the seizure onset zone, such as those involved in the interictal or "irritative" network. Methods: Neuropsychological data from 48 patients who underwent stereoelectroencephalography (SEEG) monitoring between 2012 and 2023 were reviewed. Patients were categorized based on the site of seizure onset, as well as their irritative network, to determine the impact of wider network activity on cognition. Neuropsychological data were compared with normative standards (i.e., z = 0), and between groups. Results: There were very few distinguishing cognitive features between patients when categorized based purely on the seizure onset zone (i.e., frontal lobe vs. temporal lobe epilepsy). In contrast, patients with localized irritative networks (i.e., frontal or temporal interictal epileptiform discharges [IEDs]) demonstrated more circumscribed profiles of impairment compared with those demonstrating wider irritative networks (i.e., frontotemporal IEDs). Furthermore, the directionality of propagation within the irritative network was found to influence the manifestations of cognitive impairment. Discussion: The findings suggest that neuropsychological assessment is sensitive to network activity beyond the site of seizure onset. As such, an overly focal interpretation may not accurately reflect the distribution of the underlying pathology. This has important implications for presurgical work-up in epilepsy, as well as subsequent surgical outcomes.

A meta-analytic review of prospection deficits in Parkinson's disease.

Parkinson's disease (PD) is one of the most common neurodegenerative disorders, and is associated with prominent motor deficits. However, neurocognitive impairment is also a common clinical feature that can contribute greatly to the overall disease burden. In the current study, a meta-analysis was conducted to gain a clearer understanding of how PD affects one of the most functionally important domains of cognition: prospection. The results indicate that, relative to controls, PD is associated with a large deficit in the capacity to engage in planning (g = -0.81, K = 25) and a moderate-sized deficit in prospective memory (g = -0.57, K = 16). Sub-analyses indicated that these deficits are evident for both time and event-based prospective memory, as well as for prospective memory tasks that have relatively limited ecological validity. Significant impairment was also evident for both medicated and non-medicated PD sub-groups, but for planning, these deficits were substantially greater in the unmedicated sub-group. The theoretical and practical implications of these findings are discussed.

Memory Problems in Parkinson's Disease Patients With and Without Mild Cognitive Impairment: Comparisons Between Caregiver and Self-report.

BACKGROUND: The purpose of this study was to examine differences in patient and caregiver ratings of memory function in a community sample of patients with Parkinson's disease (PD) diagnosed with and without mild cognitive impairment (PD-MCI). METHODS: One hundred sixty-five patient-caregiver pairings participated in the study. Patients with PD were administered a battery of neuropsychological tests assessing five of the key cognitive domains as indicated in the PD-MCI Movement Disorders Task Force criteria. Patients and caregivers also completed the Memory Assessment Clinics Self-Rating or Family Scale (MAC-S/MAC-F), and patients were divided into two groups, those with PD-MCI and those without. RESULTS: For patients diagnosed with PD-MCI, both patients and caregivers reported significantly more memory changes compared with patients without PD-MCI on the MAC-S and MAC-F. In contrast, for patients without PD-MCI, patients and caregivers differed significantly in their reporting of memory changes, with scores indicating that patients without PD-MCI felt their memory functioning was worse than what caregivers were reporting. CONCLUSIONS: Patients with PD without MCI might be more sensitive to memory changes than their caregivers. Whether the self-appraisal of memory problems is predictive of future cognitive difficulties, including progression to PD-MCI or PD dementia, should be the focus of future research.

Postoperative cognitive dysfunction after total joint arthroplasty in the elderly: a meta-analysis.

This meta-analysis consolidated the research on postoperative cognitive dysfunction (POCD) following total joint arthroplasty (TJA). Data from 17 studies that assessed cognition pre- and post-surgery in TJA patients alone (15 studies) or matched TJA and control groups (2 studies) were analysed. Results were grouped by cognitive domain (memory, attention, language, speed, general cognition) and follow-up interval (pre-discharge, 3-6 months post-surgery). The TJA data revealed small declines in reaction time and general cognition pre-discharge, but no evidence of decline 3-6 months post-surgery. Very limited TJA and Control data indicated no group differences in the changes to performance over time; however, the TJA group was cognitively compromised pre- and post-surgery compared to Controls. Further appropriately controlled research is required to clarify whether POCD commonly occurs after TJA.

Neuropsychologic and quality-of-life outcomes after coronary artery bypass surgery with and without cardiopulmonary bypass: a prospective randomized trial.

OBJECTIVES: The objective of this study was to compare neuropsychologic and quality-of-life outcomes of patients undergoing off-pump coronary artery bypass surgery to those undergoing coronary artery bypass graft surgery using conventional cardiopulmonary bypass. DESIGN: A prospective randomized trial of coronary artery bypass graft surgery with and without the use of cardiopulmonary bypass. SETTING: A cardiothoracic surgery unit at a tertiary hospital. PARTICIPANTS: Sixty-six patients undergoing coronary artery bypass graft surgery and a control group of 50 participants not undergoing cardiac surgery. INTERVENTIONS: Patients were randomized to receive coronary artery bypass graft surgery with cardiopulmonary bypass or randomized to coronary artery bypass graft surgery without the use of cardiopulmonary bypass. MEASUREMENTS AND MAIN RESULTS: The proportions of neuropsychologic deficits and improvement in quality-of-life were comparable regardless of whether patients were randomized to receive off-pump coronary artery bypass graft surgery or conventional coronary artery graft surgery with cardiopulmonary bypass. CONCLUSIONS: Patients receiving coronary artery bypass grafts without cardiopulmonary bypass did not show fewer cognitive deficits or greater improvement in quality of life.

Rey Complex Figure: figural and spatial memory before and after temporal lobectomy for intractable epilepsy.

Reliable neuropsychological markers of right temporal integrity have proven elusive. Specifically it is unclear whether figural and spatial aspects of visual memory are differentially affected by right temporal lobe epilepsy (TLE) and subsequent resection. To investigate this we used the modified Rey Complex Figure (RCF) scoring system devised by Brier et al. (1996) to obtain separate indices of figural and spatial memory in TLE surgery candidates. We extended on their study by examining presurgical performance and change following right and left temporal lobectomy (RATL, n = 38, LATL, n = 42) in individuals from a cross-institutional sample with and without hippocampal sclerosis (HS(+)/HS(-)). Contrary to expectation neither figural nor spatial RCF recall were differentially sensitive to RTLE, right HS, or subsequent resection. Presurgically, laterality effects on both figural and spatial memory indices were not found although HS(-) individuals significantly outperformed HS(+) individuals on both measures. Following surgery the largest decrements in both figural and spatial recall were observed among LATL HS(-) participants. We concluded that RCF recall is a poor marker of right temporal lobe function and suggest it may be a "surrogate" measure of left temporal lobe function possibly due to the verbalizability of many of its components.