Investigating higher-order cognitive functions in temporal lobe epilepsy: cognitive estimation

The role of cognitive estimation in understanding the mental states of others

Previous studies have emphasized the critical role of the prefrontal cortex in cognitive estimation and theory of mind, however, none of them has questioned the possible role of cognitive estimation processes in understanding the mental states of others. In this study, we compared 30 patients with focal prefrontal cortex damage and 30 control subjects matched by gender, age, and education level on their performances on a cognitive estimation task and two tasks assessing theory of mind: the "Faux-Pas" task and the Reading the Mind in the Eyes task. The results showed that patients were significantly impaired compared with control subjects on both abilities of cognitive estimation and theory of mind. Moreover, regression analyses showed that performance on theory of mind was predicted by the scores on cognitive estimation. Finally, using voxel-based lesion analysis, we identified a partially common bilaterally distributed prefrontal network involved in both these domains centred within the ventral and dorsomedial areas with extension to the dorsolateral prefrontal cortex.

The Impact of Right Temporal Lobe Epilepsy On Nonverbal Memory: Meta-regression of Stimulus- and Task-related Moderators

Nonverbal memory tests have great potential value for detecting the impact of lateralized pathology and predicting the risk of memory loss following right temporal lobe resection (TLR) for temporal lobe epilepsy (TLE) patients, but this potential has not been realized. Previous reviews suggest that stimulus type moderates the capacity of nonverbal memory tests to detect right-lateralized pathology (i.e., faces > designs), but the roles of other task-related factors have not been systematically explored. We address these limitations using mixed model meta-regression (k = 158) of right-lateralization effects (right worse than left TLE) testing the moderating effects of: 1) stimulus type (designs, faces, spatial), 2) learning format (single trial, repeated trials), 3) testing delay (immediate or long delay), and 4) testing format (recall, recognition) for three patient scenarios: 1) presurgical, 2) postsurgical, and 3) postsurgical change. Stimulus type significantly moderated the size of the right-lateralization effect (faces > designs) for postsurgical patients, test format moderated the size of the right-lateralization effect for presurgical-postsurgical change (recognition > recall) but learning format and test delay had no right-lateralization effect for either sample. For presurgical patients, none of the task-related factors significantly increased right-lateralization effects. This comprehensive review reveals the value of recognition testing in gauging the risk of nonverbal memory decline.

The contribution of the frontal lobe to creativity. Insights from epilepsy

PURPOSE

This study was aimed to evaluate the impact of frontal (FLE) and temporal lobe epilepsy (TLE) on graphic creativity.

METHODS

A hundred and six patients with FLE (n = 32) or TLE (n = 74) and 38 healthy subjects underwent a design fluency (DF) test constituted by a free and a fixed condition. For each condition, the number of correct designs, as an index of creativity, and unacceptable nonperseveration or perseveration designs were calculated. The participants also underwent a comprehensive neuropsychological battery.

RESULTS

The number of novel correct designs significantly differed between the groups: patients with FLE produced fewer designs than patients with TLE and controls, while epilepsy laterality had no effect. Patients with FLE also produced more unacceptable nonperseveration designs than controls, with no between-group differences in the perseverations. The number of novel designs was predicted by the type of epilepsy, whereas word fluency, comprehension, attention, set shifting, visual matching, and constructive praxis had no influence. This score was a sensitive marker of FLE discriminating FLE cognitive pattern from the pattern of TLE and healthy condition.

CONCLUSIONS

Left or right FLE, but not TLE, can impair graphic creativity. This finding and that DF was unrelated to other cognitive abilities suggest that creativity is a specific domain, sensitive to epilepsy-related frontal lobe dysfunctions. This behavioral approach including test accuracy may have implications in defining FLE cognitive phenotype.

The right anterior temporal lobe critically contributes to magnitude knowledge

Cognitive estimation is a mental ability applied to solve numerical problems when precise facts are unknown, unavailable or impractical to calculate. It has been associated with several underlying cognitive components, most often with executive functions and semantic memory. Little is known about the neural correlates of cognitive estimation. To address this issue, the present cross-sectional study applied lesion-symptom mapping in a group of 55 patients with left hemineglect due to right-hemisphere stroke. Previous evidence suggests a high prevalence of cognitive estimation impairment in these patients, as they might show a general bias towards large magnitudes. Compared to 55 age- and gender-matched healthy controls, the patient group demonstrated impaired cognitive estimation. However, the expected large magnitude bias was not found. Lesion-symptom mapping related their general estimation impairment predominantly to brain damage in the right anterior temporal lobe. Also critically involved were the right uncinate fasciculus, the anterior commissure and the right inferior frontal gyrus. The main findings of this study emphasize the role of semantic memory in cognitive estimation, with reference to a growing body of neuroscientific literature postulating a transmodal hub for semantic cognition situated in the bilateral anterior temporal lobe. That such semantic hub function may also apply to numerical knowledge is not undisputed. We here propose a critical contribution of the right anterior temporal lobe to at least one aspect of number processing, i.e. the knowledge about real-world numerical magnitudes.

From adagio to allegretto: The changing tempo of theta frequencies in epilepsy and its relation to interneuron function

Despite decades of research, our understanding of epilepsy, including how seizures are generated and propagate, is incomplete. However, there is growing recognition that epilepsy is more than just the occurrence of seizures, with patients often experiencing comorbid deficits in cognition that are poorly understood. In addition, the available therapies for treatment of epilepsy, from pharmaceutical treatment to surgical resection and seizure prevention devices, often exacerbate deficits in cognitive function. In this review, we discuss the hypothesis that seizure generation and cognitive deficits have a similar pathological source characterized by, but not limited to, deficits in theta oscillations and their influence on interneurons. We present a new framework that describes oscillatory states in epilepsy as alternating between hyper- and hypo-synchrony rather than solely the spontaneous transition to hyper-excitability characterized by the seizures. This framework suggests that as neural oscillations, specifically in the theta range, vary their tempo from a slowed almost adagio tempo during interictal periods to faster, more rhythmic allegretto tempo preictally, they impact the function of interneurons, modulating their ability to control seizures and their role in cognitive processing. This slow wave oscillatory framework may help explain why current therapies that work to reduce hyper-excitability do not completely eliminate seizures and often lead to exacerbated cognitive deficits.

Cognitive Impairment and Personality Traits in Epilepsy: Characterization and Risk Factor Analysis

Cognitive impairment and personality disorders are severe comorbidities commonly observed in patients with epilepsy, and together they decrease the quality of patients' life. This study aimed to evaluate cognitive function and personality traits in patients with epilepsy with the Wechsler Adult Intelligence Scale-Chinese revised and Eysenck Personality Questionnaire and investigate the underlying influencing factors. Compared with the control group, our results showed that patients with epilepsy were presented with significant cognitive impairment and particular personality traits. Epileptic seizure-related factors including earlier age of onset, longer duration of epileptic history, and higher seizure frequency were significantly associated with the observed defects in cognition and personality traits. In addition, the temporal lobe was more likely to affect cognition and personality, and the left hemisphere was closely related to verbal intelligence quotient, which needs to be the focus of future research. These results will be instrumental for guiding the treatment of epilepsy.

Disentangling the relationship between cognitive estimation abilities and executive functions: a study on patients with Parkinson's disease

The cognitive estimation test (CET) measures cognitive estimation abilities: it assesses the ability to apply reasoning strategies to answer questions that usually cannot lead to a clear and exact reply. Since it requires the activation of an intricate ensemble of cognitive functions, there is an ongoing debate in the literature regarding whether the CET represents a measurement of global cognitive abilities or a pure measure of executive functions. In the present study, CET together with a neuropsychological assessment focused on executive functions was administered in thirty patients with Parkinson's disease without signs of dementia. The CET correlated with measures of verbal working memory and semantic knowledge, but not with other dimensions of executive domains, such as verbal phonemic fluency, ability to manage real-world interferences, or visuospatial reasoning. According to our results, cognitive estimation abilities appeared to trigger a defined cognitive path that includes executive functions, namely, working memory and semantic knowledge.