Children and Adolescents Show Altered Visual Working Memory Related Brain Activity More Than One Decade After Arterial Switch Operation for D-Transposition of the Great Arteries

Functional networks of working memory abilities in children with complex congenital heart disease: a sleep EEG study

Working memory is frequently impaired in children with complex congenital heart disease (CHD), but little is known about the functional neuronal correlates. Sleep slow wave activity (SWA; 1-4.5 Hz EEG power) has previously been shown to reliably map neurofunctional networks of cognitive abilities in children with and without neurodevelopmental impairments. This study investigated whether functional networks of working memory abilities are altered in children with complex CHD using EEG recordings during sleep. Twenty-one children with complex CHD (aged 10.9 [SD: 0.3] years) and 17 typically-developing peers (10.5 [0.7] years) completed different working memory tasks and an overnight high-density sleep EEG recording (128 electrodes). The combined working memory score tended to be lower in children with complex CHD (CHD group: -0.44 [1.12], typically-developing group: 0.55 [1.24], d = 0.59, p = .06). The working memory score and sleep SWA of the first hour of deep sleep were correlated over similar brain regions in both groups: Strong positive associations were found over prefrontal and fronto-parietal brain regions - known to be part of the working memory network - and strong negative associations were found over central brain regions. Within these working memory networks, the associations between working memory abilities and sleep SWA (r between -.36 and .58, all p < .03) were not different between the two groups (no interactions, all p > .05). The current findings suggest that sleep SWA reliably maps working memory networks in children with complex CHD and that these functional networks are generally preserved in these patients.

Cognitive function in adults with Fontan palliation versus acyanotic CHD patients and association with health-related quality of life

BACKGROUND

Impairments and developmental delay are often reported in infants and young children with CHD. However, currently, there is no data regarding cognitive abilities assessed by standardised intelligence tests in adults with CHD. This study assesses the cognitive function in Fontan patients compared with acyanotic CHD patients whether restrictions in cognitive function are present in adulthood and its association with health-related quality of life.

METHODS

Forty-four adult CHD (female n = 21 (47.7%); mean age 34.7 ± 11.9 years), 22 with Fontan circulation and 22 with acyanotic CHD, underwent the Wechsler Intelligence Scale for adults as patients during routine follow-up in 2018. The Medical Outcomes Study Questionnaire Short-Form 36 Health Survey (SF-36) assessed health-related quality of life.

RESULTS

Fontan patients showed significantly better results in the FSIQ (p = 0.020) and perceptual reasoning (p = 0.017) in comparison with patients with acyanotic CHD. All adult CHD patients showed normal IQ in subscales and full-scale IQ (FSIQ). In health-related quality of life, no association with cognitive function was found and no significant difference between both CHD groups, but trends to reduced values in acyanotic adult CHD.

CONCLUSIONS

Interestingly, our study results in adult Fontan patients showed that it is possible to live an adult life with normal cognitive function and good health-related quality of life with a univentricular heart. Thus, this study could be a guidepost for more in-depth studies on cognitive function in Fontan survivors. In addition, the focus should be on health-related quality of life of adult CHD with simple CHD in particular, since a reduced health-related quality of life is not only medically based.

Persistent neuronal firing in the medial temporal lobe supports performance and workload of visual working memory in humans

The involvement of the medial temporal lobe (MTL) in working memory is controversially discussed. Recent findings suggest that persistent neural firing in the hippocampus during maintenance in verbal working memory is associated with workload. Here, we recorded single neuron firing in 13 epilepsy patients (7 male) while they performed a visual working memory task. The number of coloured squares in the stimulus set determined the workload of the trial. Performance was almost perfect for low workload (1 and 2 squares) and dropped at high workload (4 and 6 squares), suggesting that high workload exceeded working memory capacity. We identified maintenance neurons in MTL neurons that showed persistent firing during the maintenance period. More maintenance neurons were found in the hippocampus for trials with correct compared to incorrect performance. Maintenance neurons increased and decreased firing in the hippocampus and increased firing in the entorhinal cortex for high compared to low workload. Population firing predicted workload particularly during the maintenance period. Prediction accuracy of workload based on single-trial activity during maintenance was strongest for neurons in the entorhinal cortex and hippocampus. The data suggest that persistent neural firing in the MTL reflects a domain-general process of maintenance supporting performance and workload of multiple items in working memory below and beyond working memory capacity. Persistent neural firing during maintenance in the entorhinal cortex may be associated with its preference to process visual-spatial arrays.

Impact of Cardiac Neurodevelopmental Evaluation for Children with Congenital Heart Disease

Children with congenital heart disease (CHD) are at increased risk for neurodevelopmental delays. This study of school-aged children with single ventricle CHD compared access to services for those who did and did not complete an evaluation. Children completing an evaluation had more academic services, including an Individualized Education Plan (66% vs 34%,P = .017), small group academic instruction (54% vs 20%,P = .01), any instructional supports (77% vs 44%,P = .008). A barrier to not completing the evaluation was lack of knowledge about the Cardiac Neurodevelopmental Program (82%). The neurodevelopmental evaluation is an impactful tool that can increase access to school services in vulnerable CHD patients.