Which clinical and neuropsychological factors are responsible for cognitive impairment in patients with epilepsy?

Impact of Polytherapy on Memory Functioning in Patients With Drug-Resistant Epilepsy: The Role of Attention and Executive Functions

OBJECTIVE

The aim was to examine the effect of polytherapy (i.e., the number of administered anti-seizure medications (ASMs)) on memory, and whether the interaction between the number of ASMs and attentional/executive functioning affect presurgical memory functioning and postsurgical memory changes in patients with drug-resistant epilepsy.

METHODS

Two studies were carried out. Study 1 consisted of a presurgical assessment of 125 adult patients, in which attention/executive function (EpiTrack screening tool) and memory were assessed (cross-sectional study). Of them, 72 patients underwent a second postsurgical evaluation, in which memory was assessed (Study 2). Patients were distributed into groups based on EpiTrack performance and number of ASMs.

RESULTS

The interaction between the number of ASMs and the attentional/executive functioning significantly affected presurgical memory, with patients with impaired EpiTrack performance taking three-four ASMs having poorer scores than patients with intact EpiTrack performance taking three-four ASMs (for all, p < .0001). This interaction also affected postsurgical memory changes, with patients with impaired Epitrack performance taking three-four ASMs having higher postsurgical decline than those with intact Epitrack performance taking three-four ASMs (for all, p < .005). No differences were found in patients taking two ASMs. Furthermore, the number of ASMs was associated with presurgical memory performance and postsurgical memory changes only in patients with impaired EpiTrack performance (for all, p < .05).

CONCLUSIONS

Our findings underline the utility of EpiTrack, together with the clinical information on the number of prescribed ASMs, to corroborate the impact of polytherapy on memory and to optimize the prediction of postsurgical memory changes.

Dynamic causal modeling of reorganization of memory and language networks in temporal lobe epilepsy

OBJECTIVE

To evaluate the alterations of language and memory functions using dynamic causal modeling, in order to identify the epileptogenic hemisphere in temporal lobe epilepsy (TLE).

METHODS

Twenty-two patients with left TLE and 13 patients with right TLE underwent functional magnetic resonance imaging (fMRI) during four memory and four language mapping tasks. Dynamic causal modeling (DCM) was employed on fMRI data to examine effective directional connectivity in memory and language networks and the alterations in people with TLE compared to healthy individuals.

RESULTS

DCM analysis suggested that TLE can influence the memory network more widely compared to the language network. For memory mapping, it demonstrated overall hyperconnectivity from the left hemisphere to the other cranial regions in the picture encoding, and from the right hemisphere to the other cranial regions in the word encoding tasks. On the contrary, overall hypoconnectivity was seen from the brain hemisphere contralateral to the seizure onset in the retrieval tasks. DCM analysis further manifested hypoconnectivity between the brain's hemispheres in the language network in patients with TLE compared to controls. The CANTAB® neuropsychological test revealed a negative correlation for the left TLE and a positive correlation for the right TLE cohorts for the connections extracted by DCM that were significantly different between the left and right TLE cohorts.

INTERPRETATION

In this study, dynamic causal modeling evidenced the reorganization of language and memory networks in TLE that can be used for a better understanding of the effects of TLE on the brain's cognitive functions.

An objective model for diagnosing comorbid cognitive impairment in patients with epilepsy based on the clinical-EEG functional connectivity features

Objective

Cognitive impairment (CI) is a common disorder in patients with epilepsy (PWEs). Objective assessment method for diagnosing CI in PWEs would be beneficial in reality. This study proposed to construct a diagnostic model for CI in PWEs using the clinical and the phase locking value (PLV) functional connectivity features of the electroencephalogram (EEG).

Methods

PWEs who met the inclusion and exclusion criteria were divided into a cognitively normal (CON) group (n = 55) and a CI group (n = 76). The 23 clinical features and 684 PLV _EEG features at the time of patient visit were screened and ranked using the Fisher score. Adaptive Boosting (AdaBoost) and Gradient Boosting Decision Tree (GBDT) were used as algorithms to construct diagnostic models of CI in PWEs either with pure clinical features, pure PLV _EEG features, or combined clinical and PLV _EEG features. The performance of these models was assessed using a five-fold cross-validation method.

Results

GBDT-built model with combined clinical and PLV _EEG features performed the best with accuracy, precision, recall, F1-score, and an area under the curve (AUC) of 90.11, 93.40, 89.50, 91.39, and 0.95%. The top 5 features found to influence the model performance based on the Fisher scores were the magnetic resonance imaging (MRI) findings of the head for abnormalities, educational attainment, PLV _EEG in the beta (β)-band C3-F4, seizure frequency, and PLV _EEG in theta (θ)-band Fp1-Fz. A total of 12 of the top 5% of features exhibited statistically different PLV _EEG features, while eight of which were PLV _EEG features in the θ band.

Conclusion

The model constructed from the combined clinical and PLV _EEG features could effectively identify CI in PWEs and possess the potential as a useful objective evaluation method. The PLV _EEG in the θ band could be a potential biomarker for the complementary diagnosis of CI comorbid with epilepsy.

Cognitive adverse effects of epilepsy and its predictors attending outpatient department of South Gondar zone hospitals, Amhara Region, Ethiopia 2020 /2021

BACKGROUND

Epilepsy is the most common neurologic disorder which is further complicated by neurobehavioral co-morbidities, cognitive impairment, psychiatric disorders, and social problems. However, assessments of cognitive status of epileptic patients are far too low during clinical visits. This calls for early neuropsychological assessment soon after the diagnosis of epilepsy for a better treatment plan and outcome for epileptic patients.

OBJECTIVE

This study aimed to assess the cognitive adverse effects of epilepsy and its predictors attending outpatient departments of South Gondar Zone hospitals Amhara region Ethiopia 2020/2021.

METHODS

A multi-center institutional-based cross-sectional study was conducted. A total of 509 respondents were included with a response rate of 93.9%. Previously adapted pretested structured questionnaire was used containing, socio-demographic, clinical, and seizure related factors. Mini-Mental State Examination (MMSE) was used to measure cognitive impairment. A systematic random sampling technique was applied. Data were entered into Epi data version 4.4.2 then exported to SPSS version 24 for analysis. Descriptive statistics, bivariable and multivariable binary logistic regressions with odds ratios and 95% confidence interval were employed. The level of significance of association was determined at a p-value < 0.05.

RESULTS

Prevalence of cognitive impairment in this study was 69.2% (95%CI; 65.4, 73.1). Rural residents (AOR = 4.16,95%CI, 1.99,8.67), respondents who couldn't read and write (AOR = 2.62, 95%CI; 1.24, 5.5,) longer duration of seizure disorder (AOR = 4.59,95%CI; 2.01,10.52), taking combined Phenobarbital and Phenytoin (AOR = 4.69,95%CI; 1.88,11.69), having history of head injury (AOR = 3.29,95%CI;1.30,8.32), having depression (AOR = 4.76,95%CI;2.83,7.98), and anxiety (AOR = 3.11,95%CI; 1.58,6.12) were significantly associated with cognitive impairment.

CONCLUSIONS

Prevalence of cognitive impairment in this study was high. Regular neuropsychiatric assessment of patients with epilepsy should be encouraged especially for those participants with longer durations of illness, who are rural residents, who take combined Phenobarbital and Phenytoin, participants who had a history of head injury, depression, and anxiety.

Clinical utility of Epitrack for differentiating profiles and patterns of post-surgical change in memory and quality of life in patients with drug-resistant epilepsy

PURPOSE

To assess whether performance in attention and executive functions evaluated with the Epitrack screening tool before surgery can differentiate memory and quality of life (QOL) profiles, and detect different post-surgical change patterns in these variables in patients with epilepsy.

METHODS

This is a longitudinal study. Seventy-seven patients with drug-resistant epilepsy (mean age = 37.91) underwent a neuropsychological assessment before and one year after surgery. Epitrack, a screening tool that exclusively evaluates attention and executive functioning, was administered in the pre-surgical assessment, and verbal and visual memory and QOL were assessed before and after surgery.

RESULTS

Patients with impaired Epitrack performance had poorer verbal and visual memory than those with intact Epitrack performance, regardless of the time point (for all, p < 0.0001). They also showed a post-surgical decline in immediate verbal recall (p = 0.04) and discriminability (p = 0.001). Patients with intact Epitrack performance did not exhibit this decline. Epitrack total score significantly contributed to 13 and 11% of the variance of post-surgical changes in immediate verbal recall and discriminability, respectively. Epitrack groups did not differ in QOL profiles or changes, but post-surgical immediate verbal recall improvements were related to post-surgical QOL improvements.

CONCLUSION

Our findings underline the utility of Epitrack screening tool to detect different patterns of verbal and visual memory dysfunction, as well as to predict post-surgical verbal memory decline in patients with drug-resistant epilepsy. Patients with lower pre-surgical Epitrack scores appear to be at increased risk for post-surgical memory decline.

Mapping of Language-and-Memory Networks in Patients With Temporal Lobe Epilepsy by Using the GE2REC Protocol

Preoperative mapping of language and declarative memory functions in temporal lobe epilepsy (TLE) patients is essential since they frequently encounter deterioration of these functions and show variable degrees of cerebral reorganization. Due to growing evidence on language and declarative memory interdependence at a neural and neuropsychological level, we propose the GE2REC protocol for interactive language-and-memory network (LMN) mapping. GE2REC consists of three inter-related tasks, sentence generation with implicit encoding (GE) and two recollection (2REC) memory tasks: recognition and recall. This protocol has previously been validated in healthy participants, and in this study, we showed that it also maps the LMN in the left TLE (N = 18). Compared to healthy controls (N = 19), left TLE (LTLE) showed widespread inter- and intra-hemispheric reorganization of the LMN through reduced activity of regions engaged in the integration and the coordination of this meta-network. We also illustrated how this protocol could be implemented in clinical practice individually by presenting two case studies of LTLE patients who underwent efficient surgery and became seizure-free but showed different cognitive outcomes. This protocol can be advantageous for clinical practice because it (a) is short and easy to perform; (b) allows brain mapping of essential cognitive functions, even at an individual level; (c) engages language-and-memory interaction allowing to evaluate the integrative processes within the LMN; (d) provides a more comprehensive assessment by including both verbal and visual modalities, as well as various language and memory processes. Based on the available postsurgical data, we presented preliminary results obtained with this protocol in LTLE patients that could potentially inform the clinical practice. This implies the necessity to further validate the potential of GE2REC for neurosurgical planning, along with two directions, guiding resection and describing LMN neuroplasticity at an individual level.

Neurobehavioural comorbidities of epilepsy: towards a network-based precision taxonomy

Cognitive and behavioural comorbidities are prevalent in childhood and adult epilepsies and impose a substantial human and economic burden. Over the past century, the classic approach to understanding the aetiology and course of these comorbidities has been through the prism of the medical taxonomy of epilepsy, including its causes, course, characteristics and syndromes. Although this 'lesion model' has long served as the organizing paradigm for the field, substantial challenges to this model have accumulated from diverse sources, including neuroimaging, neuropathology, neuropsychology and network science. Advances in patient stratification and phenotyping point towards a new taxonomy for the cognitive and behavioural comorbidities of epilepsy, which reflects the heterogeneity of their clinical presentation and raises the possibility of a precision medicine approach. As we discuss in this Review, these advances are informing the development of a revised aetiological paradigm that incorporates sophisticated neurobiological measures, genomics, comorbid disease, diversity and adversity, and resilience factors. We describe modifiable risk factors that could guide early identification, treatment and, ultimately, prevention of cognitive and broader neurobehavioural comorbidities in epilepsy and propose a road map to guide future research.

Cognitive changes in patients with epilepsy identified through the MoCA test during neurology outpatient consultation

INTRODUCTION

Epilepsy is a chronic neurological disorder that may occur alongside cognitive changes, with effects on multiple cognitive domains.

OBJECTIVE

To compare the cognitive performance of patients with epilepsy and healthy controls through Montreal Cognitive Assessment (MoCA) during outpatient consultation at a reference diagnostic center in Colombia and analyze and the influencing factors.

MATERIALS AND METHODOLOGY

One-hundred and four patients during neurology outpatient consultation in the city of Cartagena, Colombia, were assessed with the (MoCA) test, i.e., 54 people who consulted for headache and have not been diagnosed with epilepsy (NEP) and 50 with a diagnosis of epilepsy (EPs) according to the diagnostic criteria of the International League Against Epilepsy (ILAE).

RESULTS

Significant differences were found in the total mean scores of the (MoCA) between (EPs) and (NPE) groups (t = 4.72; p < 0.01), particularly in attention (t = 3.22; p < 0.02) and memory (t = 5.04; p < 0.01) dimensions. Additionally, a significant association was observed between years of schooling and (MoCA) scores (p = 0,019) but not between socioeconomic level (p = 0,510), age (p = 0,452) and the frequency of seizures (p = 0,471).

DISCUSSION

Patients with epilepsy show lower scores in several cognitive domains in respect of the control group. The (MoCA) has proven its appropriateness for cognitive screening in the contexts of clinical neurology outpatient consultation.