Face and facial expression memory in temporal lobe epilepsy patients: preliminary results

Assessing spatial memory using the Brown Location Test: Lateralizing seizures in a presurgical cohort of patients with temporal lobe epilepsy

OBJECTIVE

Whilst the dominant temporal lobe has a well-established role in memory, the functions of its nondominant counterpart remain enigmatic. We compared the lateralizing ability of a promising spatial memory task (Brown Location Test, BLT) to other commonly used verbal and visual memory tasks in a sample of patients with unilateral temporal lobe epilepsy (TLE).

METHODS

Neuropsychological data from 48 TLE patients (right n = 28 and left n = 20) were compared on several verbal and nonverbal memory tasks. Univariate logistic regression analyses were used to examine the relationship between test scores and the odds of being categorised as right or left TLE, while multivariable logistic regression and decision tree analyses were used to establish the optimal combination of cognitive measures for lateralizing the epileptogenic zone (EZ).

RESULTS

Relative to normative expectations, the right TLE group was specifically impaired on BLT measures, whereas the left TLE group was impaired on verbal and nonverbal memory tasks. The combination of BLT Delayed Recall and Delayed Recall on the Rey Auditory Verbal Learning Task (RAVLT) was identified as optimal for correctly predicting EZ laterality (AUC = 0.79). These two variables were also optimal predictors in the decision tree analysis, correctly predicting 79% of the overall sample (AUC = 0.83).

CONCLUSIONS

Our findings support the BLT as a measure of right temporal lobe function. They demonstrate its superior sensitivity compared to another commonly used nonverbal memory test (i.e., Visual Reproduction; VR) and highlight the added lateralizing value of combining both verbal and nonverbal memory measures in the neuropsychological evaluation of epilepsy surgery candidates.

Toward social neuropsychology of epilepsy: a meta-analysis on social cognition in epilepsy phenotypes and a critical narrative review on assessment methods

Background

The aim of this review is to (a) characterize social cognition impairments in the domains of emotion recognition (ER) and theory of mind (ToM) in patients with epilepsy and (b) to review assessment tools with a focus on their validity and usability in clinical practice.

Methods

An electronic search for clinical studies investigating social cognition in epilepsy populations vs healthy control subjects (HC) yielded 53 studies for the meta-analysis and descriptive review.

Results

Results suggest that (1) social cognition is significantly impaired in patients with temporal lobe epilepsy (TLE), frontal lobe epilepsy (FLE) and patients with epilepsy not originating within the temporal or frontal lobes including idiopathic generalized epilepsies (eTLE/eFLE); (2) there is no significant difference between eTLE/eFLE and TLE regarding ER, while TLE and FLE patients perform worse than those with eTLE/eFLE, without significant differences between FLE and TLE regarding ToM ability. A descriptive analysis of the most commonly used assessment tools and stimulus material in this field revealed a lack of ecological validity, usability, and economic viability for everyday clinical practice.

Conclusions

Our meta-analysis shows that patients with epilepsy are at a significantly increased risk of deficits in social cognition. However, the underlying multifactorial mechanisms remain unclear. Future research should therefore specifically address the impairment of processing and methodological problems of testing.

Lesion side matters - an fMRI study on the association between neural correlates of watching dynamic fearful faces and their evaluation in patients with temporal lobe epilepsy

Most studies assessing facial affect recognition in patients with TLE reported emotional disturbances in patients with TLE. Results from the few fMRI studies assessing neural correlates of affective face processing in patients with TLE are divergent. Some, but not all, found asymmetrical mesiotemporal activations, i.e., stronger activations within the hemisphere contralateral to seizure onset. Little is known about the association between neural correlates of affect processing and subjective evaluation of the stimuli presented. Therefore, we investigated the neural correlates of processing dynamic fearful faces in 37 patients with mesial temporal lobe epilepsy (TLE; 18 with left-sided TLE (lTLE), 19 with right-sided TLE (rTLE)) and 20 healthy subjects. We additionally assessed individual ratings of the fear intensity and arousal perception of the fMRI stimuli and correlated these data with the activations induced by the fearful face paradigm and activation lateralization within the mesiotemporal structures (in terms of individual lateralization indices, LIs). In healthy subjects, whole-brain analysis showed bilateral activations within a widespread network of mesial and lateral temporal, occipital, and frontal areas. The patient groups activated different parts of this network. In patients with lTLE, we found predominantly right-sided activations within the mesial and lateral temporal cortices and the superior frontal gyrus. In patients with rTLE, we observed bilateral activations in the posterior regions of the lateral temporal lobe and within the occipital cortex. Mesiotemporal region-of-interest analysis showed bilateral symmetric activations associated with watching fearful faces in healthy subjects. According to the region of interest and LI analyses, in the patients with lTLE, mesiotemporal activations were lateralized to the right hemisphere. In the patients with rTLE, we found left-sided mesiotemporal activations. In patients with lTLE, fear ratings were comparable to those of healthy subjects and were correlated with relatively stronger activations in the right compared to the left amygdala. Patients with rTLE showed significantly reduced fear ratings compared to healthy subjects, and we did not find associations with amygdala lateralization. Although we found stronger activations within the contralateral mesial temporal lobe in the majority of all patients, our results suggest that only in the event of left-sided mesiotemporal damage is the right mesial temporal lobe able to preserve intact facial fear recognition. In the event of right-sided mesiotemporal damage, fear recognition is disturbed. This underlines the hypothesis that the right amygdala is biologically predisposed to processing fear, and its function cannot be fully compensated in the event of right-sided mesiotemporal damage.

Verbal emotional memory in children and adolescents with temporal lobe epilepsy: a first study

That emotional memory enhancement is compromised in adult patients with temporal lobe epilepsy (TLE), particularly in the case of early cerebral damage, has been suspected. We conducted a study in which we compared 20 children and adolescents aged 11-15 years with early TLE with 40 healthy control subjects. We studied the effect of emotional information on verbal memory performance using story recall and word list learning tasks. Our results highlighted the existence of emotional memory facilitation in healthy subjects, whereas there was no beneficial impact of emotional material on memory in young patients with TLE. Our study suggests that early TLE can impair the development of emotional memory processes.

Facial emotion recognition impairment in chronic temporal lobe epilepsy

PURPOSE

To evaluate facial emotion recognition (FER) in a cohort of 176 patients with chronic temporal lobe epilepsy (TLE).

METHODS

FER was tested by matching facial expressions with the verbal labels for the following basic emotions: happiness, sadness, fear, disgust, and anger. Emotion recognition performances were analyzed in medial (n = 140) and lateral (n = 36) TLE groups. Fifty healthy subjects served as controls. The clinical and neuroradiologic variables potentially affecting the ability to recognize facial expressions were taken into account.

RESULTS

The medial TLE (MTLE) group showed impaired FER (86% correct recognition) compared to both the lateral TLE patients (FER = 93.5%) and the controls (FER = 96.4%), with 42% of MTLE patients recording rates of FER that were lower [by at least 2 standard deviations (SDs)] than the control mean. The MTLE group was impaired compared to the healthy controls in the recognition of all basic facial expressions except happiness. The patients with bilateral MTLE were the most severely impaired, followed by the right and then the left MTLE patients. FER was not affected by type of lesion, number of antiepileptic drugs (AEDs), aura semiology, or gender. Conversely, the early onset of seizures/epilepsy was related to FER deficits. These deficits were already established in young adulthood, with no evidence of progression in older MTLE patients.

CONCLUSION

These results on a large cohort of TLE patients demonstrate that emotion recognition deficits are common in MTLE patients and widespread across negative emotions. We confirm that early onset seizures with right or bilateral medial temporal dysfunction lead to severe deficits in recognizing facial expressions of emotions.

Perception and recall of faces and facial expressions following temporal lobectomy

The perception of and memory for faces, with or without emotional content, were studied in 43 patients with temporal lobe epilepsy who had undergone unilateral resection of the hippocampus and the amygdala and in 43 healthy participants for comparison. Each participant performed four tasks from the Florida Affect Battery (Facial Discrimination, Affect Discrimination, Affect Naming, Affect Selection) and two memory tasks (in one case of a face and in the other of a facial expression). Findings indicated that, although patients with unilateral temporal lobectomy (right or left) showed no difficulty in discriminating faces, they were not as good at remembering faces. Also, patients who had had a left temporal lobectomy showed impairment in discriminating facial expressions, in the memory of a facial expression and/or in naming facial expressions.

T2 relaxation time correlates of face recognition deficits in temporal lobe epilepsy

This study explored structural correlates of immediate and delayed face recognition in 22 nonsurgical patients with nonlesional, unilateral mesial temporal lobe epilepsy (TLE, 10 left/12 right). We measured T2 relaxation time bilaterally in the hippocampus, the amygdala, and the fusiform gyrus. Apart from raised T2 values in the ipsilateral hippocampus, we found increased T2 values in the ipsilateral amygdala. Patients with right TLE exhibited impaired face recognition as a result of a decrease from immediate to delayed recognition. Higher T2 values in the right than left fusiform gyrus or hippocampus were related to worse immediate face recognition, but did not correlate with 24-hour face recognition. These preliminary results indicate that structural changes in the fusiform gyrus and hippocampus may influence immediate face recognition deficits, but have no linear influence on long-term face recognition in TLE. We suggest that long-term face recognition depends on a right hemispheric network encompassing structures outside the temporal lobe.

Face memory in MRI-positive and MRI-negative temporal lobe epilepsy

PURPOSE

Effects of MRI-positive (MRI(+)) as compared to MRI-negative (MRI(-)) temporal lobe epilepsy (TLE) on face memory are not yet known.

METHODS

We studied 24 MRI(-) (11 right/13 left) and 20 MRI(+) (13 right/7 left) TLE patients, 12 generalized epilepsy patients, and 12 healthy subjects undergoing diagnostic workup with 24-72-h Video-EEG-monitoring. Twenty faces were shown, and had to be recognized from 40 faces immediately and after a 24-h delay.

RESULTS

MRI(+) and MRI(-) right TLE (RTLE) patients showed deficits in face recognition compared to controls or generalized epilepsy, consistent with right temporal lobe dominance for face recognition. MRI(+) RTLE patients had deficits in both immediate and delayed recognition, while MRI(-) RTLE patients showed delayed recognition deficits only. The RTLE groups showed comparable delayed recognition deficits. Separate analyses in which the MRI(+) group included patients with hippocampal sclerosis only, did not alter results. Furthermore, MRI(-) RTLE had a worse delayed recognition than MRI(-) left TLE (LTLE). On the other hand, MRI(+) RTLE did not differ from MRI(+) LTLE in delayed recognition. Combining MRI(-) and MRI(+) TLE groups, we found differences between RTLE and LTLE in delayed, but not immediate face recognition.

CONCLUSIONS

Our results suggest that a delayed recognition condition might be superior to immediate recognition tests in detecting face memory deficits in MRI(-) RTLE patients. This might explain why former studies in preoperative patients did not observe an immediate face recognition dominance of the right temporal lobe when combining MRI(-) and MRI(+) TLE patients. Our data further point to an important role of the right mesial temporal region in face recognition in TLE.

Sex differences in face recognition memory in patients with temporal lobe epilepsy, patients with generalized epilepsy, and healthy controls

The influence of sex on face recognition memory was studied in 49 patients with temporal lobe epilepsy, 20 patients with generalized epilepsy, and 32 healthy controls. After learning 20 faces, serially presented for 5 seconds each, subjects had to recognize the 20 among 40 faces (including 20 new faces) immediately and 24 hours later. Women had better face recognition than men, with no significant differences between groups. Women's advantage was due mainly to superior delayed recognition. Taken together, the results suggest that sex has a similar impact on face recognition in patients with epilepsy and healthy controls, and that testing delayed face recognition raises sensitivity for sex differences. The influence of sex on face recognition in patients with epilepsy should be acknowledged when evaluating individuals or comparing groups.

Recognition of emotion with temporal lobe epilepsy and asymmetrical amygdala damage

PURPOSE

Impairments in emotion recognition occur when there is bilateral damage to the amygdala. In this study, ability to recognize auditory and visual expressions of emotion was investigated in people with asymmetrical amygdala damage (AAD) and temporal lobe epilepsy (TLE).

METHODS

Recognition of five emotions was tested across three participant groups: those with right AAD and TLE, those with left AAD and TLE, and a comparison group. Four tasks were administered: recognition of emotion from facial expressions, sentences describing emotion-laden situations, nonverbal sounds, and prosody.

RESULTS

Accuracy scores for each task and emotion were analysed, and no consistent overall effect of AAD on emotion recognition was found. However, some individual participants with AAD were significantly impaired at recognizing emotions, in both auditory and visual domains.

CONCLUSIONS

The findings indicate that a minority of individuals with AAD have impairments in emotion recognition, but no evidence of specific impairments (e.g., visual or auditory) was found.

Epilepsy increases vulnerability of long-term face recognition to proactive interference

Proactive interference (PI) decreases short- and long-term memory in healthy subjects. Neurological patients exhibit a heightened PI effect on short-term memory. It is, however, not known if PI affects long-term memory in neurological patients. We analyzed whether epilepsy heightens the negative effect of PI on long-term face memory. PI was induced by a list of 20 faces learned 24 hours prior to a target list of 20 faces. We tested immediate and 24-hour recognition for both lists. Twelve healthy controls and 42 patients with generalized epilepsy or temporal lobe epilepsy (TLE) were studied. PI led to a decrease in 24-hour recognition in patients with generalized epilepsy and TLE but not in controls. Thus, PI may cause long-term memory disturbances in epilepsy patients. PI was also associated with decreased short-term memory, but only in right TLE. This confirms the dominant role of the right temporal lobe in short-term face memory.

Social cognition and epilepsy surgery

Human social behavior depends on a set of perceptive, mnemonic, and interpretive abilities that together may be termed social cognition. Lesion and functional imaging studies of social cognitive functions implicate the temporal lobes (in particular, the nondominant temporal lobe) and mesial temporal structures as critical at the front end of social cognitive processes. The frontal lobes, in turn, function to interpret and to modulate these processes via top-down control. Damage to frontal regions is associated with specific derangements in social behavior. Chronic focal-onset epilepsy and its surgical treatment commonly affect these neuroanatomic regions and might therefore impact social function. Postoperative social function helps determine quality of life for both patients and families. There is some evidence that resective seizure surgery affects social cognition, but there are significant weaknesses in our current knowledge that can be overcome with comprehensive longitudinal research.