Assessment of temporal changes in cognitive effects induced by antiseizure medications in epilepsy patients

OBJECTIVE

Numerous studies have been conducted investigating the effects of antiseizure medications (ASMs) on cognitive functions, and the cognitive side effects of some ASMs have been demonstrated. However, data on whether tolerance to these side effects develops over time is insufficient. The aim of this study is to evaluate the reversibility of cognitive impairments caused by ASMs in patients, utilizing event-related potentials (ERPs) and the Montreal Cognitive Assessment (MoCA) test.

MATERIALS AND METHODS

The single-center prospective study was conducted from July 2022 to August 2023. This study enrolled participants aged 18 to 50 who had been diagnosed with epilepsy and were planning to commence treatment with an antiseizure medication (ASM). The inclusion criteria comprised individuals aged between 18 and 50 years, with a diagnosis of epilepsy, and who were intending to initiate a new ASM as monotherapy. Exclusion criteria encompassed individuals younger than 18 or older than 50 years, those diagnosed with psychogenic non-epileptic seizures, those currently on antiepileptic drugs, and those with cognitive dysfunction or dementia. Before starting treatment, patients were subjected to the MoCA test and ERP measurements by a neurologist. These tests and measurements were repeated at the second and sixth months of treatment.

RESULT

The study included a cohort of 254 participants with a mean age of 32.6 (±14) years. At the second month after starting treatment with carbamazepine (CBZ), zonisamide (ZNS), valproic acid (VPA), and topiramate (TPM), both MoCA and ERP values showed significantly worse cognitive impairment compared to before treatment (p < 0.05). This impairment showed a significant improvement by the sixth month for CBZ, ZNS, and VPA (p < 0.05). Although there was improvement in MoCA and ERP values in patients using TPM, the changes remained statistically significant compared to baseline values (p < 0.05). In patients using levetiracetam, lamotrigine, oxcarbazepine, and lacosamide, cognitive impairment was not statistically significant at either the second or sixth month.

CONCLUSION

This study demonstrated that the detrimental cognitive effects associated with CBZ, VPA, and ZNS could be reversible. Although some improvement was observed over time with TPM, the absence of significant recovery suggests that additional time may be required for a substantial reversal of these effects.

Neurocognitive deficits in male alcoholics: an ERP/sLORETA analysis of the N2 component in an equal probability Go/NoGo task

In alcoholism research, studies concerning time-locked electrophysiological aspects of response inhibition have concentrated mainly on the P3 component of the event-related potential (ERP). The objective of the present study was to investigate the N2 component of the ERP to elucidate possible brain dysfunction related to the motor response and its inhibition using a Go/NoGo task in alcoholics. The sample consisted of 78 abstinent alcoholic males and 58 healthy male controls. The N2 peak was compared across group and task conditions. Alcoholics showed significantly reduced N2 peak amplitudes compared to normal controls for Go as well as NoGo task conditions. Control subjects showed significantly larger NoGo than Go N2 amplitudes at frontal regions, whereas alcoholics did not show any differences between task conditions at frontal regions. Standardized low resolution electromagnetic tomography analysis (sLORETA) indicated that alcoholics had significantly lower current density at the source than control subjects for the NoGo condition at bilateral anterior prefrontal regions, whereas the differences between groups during the Go trials were not statistically significant. Furthermore, NoGo current density across both groups revealed significantly more activation in bilateral anterior cingulate cortical (ACC) areas, with the maximum activation in the right cingulate regions. However, the magnitude of this difference was much less in alcoholics compared to control subjects. These findings suggest that alcoholics may have deficits in effortful processing during the motor response and its inhibition, suggestive of possible frontal lobe dysfunction.

Attention and aging

BACKGROUND AND AIMS

Aging is a condition characterized by a general decline in many types of physical and psychological performance, but its effects on various cognitive functions are still controversial. When viewed along a time-course, several abilities clearly differ in their stability or decline with aging. Among psychological functioning in the elderly, changes in attention are not fully understood. The aim of our research was to analyze attentive performance in a sample of subjects aged 55-65, evaluating various aspects of attentive functioning with respect to the gender variable and to verify if aging affects all attentive functions equally.

METHODS

The sample included 80 subjects (44 men, 36 women) of 55-65 years of age. Attentional abilities were evaluated by means of multitask computerized assessment. The test involved seven tasks assessing simple reaction times and choice reaction times, visual, visual-spatial and auditory selectivity, digit span, divided attention, resistance to distraction, and attentive shifting.

RESULTS

Significant differences related to gender were found in attention shifting. To test possible decline in attentive function with age, performances among two age groups (55-59 and 60-65 yrs) were compared. Significant differences were shown in simple immediate attention span, selectivity, capacity to inhibit interference of non-pertinent signals, and attentive shifting.

CONCLUSIONS

This study demonstrates an age-related reduction in attentive efficiency but, notably, this decline does not involve all components of attention. Subjects over 60 years of age show progressive slowing in processing of complex tasks and a reduced capacity to inhibit irrelevant stimuli.

Attention to features of separate objects: an ERP study of target-shooters and control participants

In a visual discrimination task stimuli consisted of a color circle and a grating pattern, i.e. target features were distributed between two objects. The relation (hierarchical vs. parallel) between the attentional processing of the task-related features (color and spatial frequency) was investigated by using the methods of event-related potentials (ERPs). Participants with considerable practice in visual attention (target shooters; n = 13) were compared to control subjects (n = 11). Attention-related ERP components, i.e. selection (anterior) positivity (SP), selection negativity (SN), N2 (N2b), furthermore the late positivity (P3b) emerged only if the circle had relevant color. These results suggest preponderance of color processing. Target shooters were faster and more accurate than the control group. Attention-related components (SP, N2b) and the late positivity (P3b) were larger in shooters, but the relations among the attention-related components were the same in two groups, showing similar progression of the target selection process.