Psychosocial and Neurobehavioral Factors Related to Surgical Treatment for Partial Epilepsy: A Multivariate Analysis

A systematic review of neuroimaging studies of depression in adults with epilepsy

OBJECTIVE

Depression is a relatively common comorbidity in people with epilepsy with a lifetime history identified in 1 in 4 individuals. In this paper, we aimed to provide a systematic review of structural and functional brain region-specific group differences of adults with epilepsy and depression and to discuss existing evidence as compared to that in people with depression.

METHODS

We undertook a systematic review of neuroimaging studies of depression in adults with epilepsy through MEDLINE/PubMed, Embase and PsycInfo searches until June 2020.

RESULTS

A total of 44 studies were included in the qualitative synthesis: 21 on structural neuroimaging, 9 on functional, and 14 on pharmaco/metabolic neuroimaging. Almost all studies focused on temporal lobe epilepsy (TLE). Patterns of changes in the hippocampi and subcortical structures seem to be different from those reported in depression outside epilepsy. Cortical changes are grossly similar as well as the lack of any laterality effect. Serotonin dysfunction seems to be due to different mechanisms with reduced synaptic availability for depression in epilepsy as compared to reduced 5HT1 receptor density outside epilepsy. Depressive symptoms seem to correlate with a dysfunction in temporolimbic structures contralateral to the epileptogenic zone especially in patients with de novo postsurgical depression.

CONCLUSIONS

Depression, at least in TLE, seems to be associated with a different pattern of brain changes as compared to major depression, potentially supporting the notion of phenomenological peculiarities of depression in epilepsy.

Predicting and preventing psychopathology following temporal lobe epilepsy surgery

Less than 3% of temporal lobe epilepsy (TLE) surgical outcome studies have investigated the psychiatric sequelae and morbidity associated with surgery. This is disproportionate to the extent of the problem. Variable prevalence rates have been reported for post-surgical depression, anxiety, and interictal psychosis. Until recently, very few studies distinguished de novo postoperative presentations from pre-existing conditions, making it difficult to accurately assess the impact of TLE surgery on psychiatric morbidity. Predictors of de novo postoperative presentations have proved elusive. This current review summarizes the findings from a systematic literature review of the psychiatric morbidity associated with TLE surgery including newly published follow-up data from our own series of 280 surgical patients. A framework for future research, possible pathophysiological mechanisms, and translational models are also discussed.

Altered T2* relaxation time of the hippocampus in major depressive disorder: implications of ultra-high field magnetic resonance imaging

Previous studies with 1.5 T or 3.0 T magnetic resonance imaging (MRI) have produced mixed results regarding the structural changes of the hippocampus in major depressive disorder (MDD). Subtle region-specific hippocampal tissue changes might be more sensitively detected by measuring the T2* relaxation time (T2*-RT) by ultra-high-field (UHF) MRI, as it provides much higher contrast and sensitivity and consequently greater resolution. We assessed the T2*-RTs of hippocampal sub-regions in 16 MDD patients (9 with recurrent MDD) and 16 control subjects using an UHF 7.0 T MRI system. T2*-RTs of CA1, CA2, CA3, CA4, and subiculum were calculated for both left and right hippocampus. MDD patients had significantly longer T2*-RTs in the right CA1 and subiculum than control subjects. Patients with recurrent MDD had significantly longer T2*-RTs in the right subiculum than those experiencing a first depressive episode, and longer T2*-RTs in the right CA1, CA3, and subiculum than control subjects. Values for T2*-RTs of the right CA3 were significantly correlated with illness duration. In conclusion, we report that T2*-RTs in the right subiculum and CA1 were increased in patients with MDD, especially in cases of recurrent MDD. These findings suggest that region-specific hippocampal damage may be occurring in recurrent depression.

Quality of life after surgery for temporal lobe epilepsy: a 5-year follow-up

The authors carried out a 5-year prospective study about the effects epilepsy surgery can have on a patient's quality of life (QOL). They looked for the relationship between improvement on QOL after surgery and reduction of seizure frequency, seizure focus, age at surgery and previous psychopathology. They concluded that improvement in overall, cognitive and social function scores were statistically significant throughout the study. Seizure worry score ceased to be significant at the fifth year. Previous psychopathology was a negative influence on social and seizure worry score. Compared to left lobectomies, right lobectomies showed significant better results in overall scores at six months and one year follow-up. At 1 month follow-up, cognitive function was also significantly better in right lobectomies. Engels class I patients demonstrated statistically better results in the fourth and fifth years of follow-up. Neither years of disease nor patient age at surgery seemed to influence QOL.

Temporal lobe epilepsy, depression, and hippocampal volume

OBJECTIVE

To evaluate the relationship between hippocampal volume loss, depression, and epilepsy.

BACKGROUND

There is a significantly increased incidence of depression and suicide in patients with epilepsy. Both epilepsy and depression are associated with reduced hippocampal volumes, but it is uncertain whether patients with both conditions have greater atrophy than those with epilepsy alone. Previous studies used depression measures strongly weighted to current state, and did not necessarily assess the influence of chronic major depressive disorder ("trait"), which could have a greater impact on hippocampal volume.

METHODS

Fifty-five epilepsy patients with complex partial seizures (CPS) confirmed by electroencephalography (EEG) had three-dimensional (3D)-spoiled gradient recall (SPGR) acquisition magnetic resonance imaging (MRI) scans for hippocampal volumetric analysis. Depression screening was performed with the Beck Depression Inventory (BDI, 51 patients) and with the structured clinical inventory for DSM-IV (SCID, 34 patients). For the BDI, a score above 10 was considered mild to moderate, above 20 moderate to severe, and above 30 severe depression. MRI and clinical analysis were performed blinded to other data. Statistical analysis was performed with Systat using Student's t test and analysis of variance (ANOVA).

RESULTS

There was a significant interaction between depression detected on SCID, side of focus, and left hippocampal volume. Patients with a diagnosis of depression and a right temporal seizure focus had significantly lower left hippocampal volume. A similar trend for an effect of depression on right hippocampal volume in patients with a right temporal focus did not reach statistical significance.

CONCLUSIONS

Our results suggest that patients with right temporal lobe epilepsy and depression have hippocampal atrophy that cannot be explained by epilepsy alone.

Psychiatric outcome of surgery for temporal lobe epilepsy and presurgical considerations

In recent years, surgery has become a treatment option for some patients with intractable epilepsy, particularly those with temporal lobe epilepsy. Psychiatric disturbances may complicate the postsurgical outcome in some patients and de novo psychiatric symptoms have been reported. In many but not all epilepsy surgical centres, a psychiatric assessment is included as part of the presurgical evaluation of potential candidates for surgery. This review indicates that affective disorders, namely, depression and anxiety, and psychosis are the most frequently reported postsurgical psychiatric disturbances. Whilst there are no absolute psychiatric contraindications to surgery, certain pre-existing psychiatric conditions may need careful consideration as there may be a risk of postsurgical psychiatric complications. Routine pre- and postsurgical psychiatric evaluations in patients undergoing epilepsy surgery are recommended. Clinicians involved in the care of surgical candidates should be aware of the possible psychiatric complications following surgery and ensure that the psychiatric risks are discussed with the patient and family.

Mood disturbance before and after seizure surgery: a comparison of temporal and extratemporal resections

PURPOSE

Mood disturbance is a common comorbid condition of temporal lobe epilepsy before and after seizure surgery. Few studies have examined mood disturbance in patients undergoing resections outside the temporal lobe (extratemporal resections). This study aimed to compare the early, postoperative evolution of mood disturbance in temporal and extratemporal lobe epilepsy patients to examine the effect of site of surgical resection on mood outcome.

METHODS

The study used a longitudinal design and was qualitative in nature. Sixty seizure surgery patients (43 temporal resections, 17 extratemporal resections) were assessed before surgery and at discharge, 1 month, and 3 months after surgery, by using the Austin CEP Interview. Psychosocial adjustment, psychiatric difficulties, including depression and anxiety, and seizure frequency were assessed.

RESULTS

Before surgery, both temporal and extratemporal patients had significant psychiatric histories with similarly high rates of depression (33 and 53%, respectively) and anxiety (23 and 18%, respectively). After surgery, significantly more temporal patients were seizure free at each of the reviews compared with extratemporal patients. Temporal patients also reported significantly higher levels of depression (26%), anxiety (42%), and psychosocial adjustment difficulties (64%) at the 1-month review than did extratemporal patients. Mood disturbance was significantly associated with adjustment difficulties in both groups, but was not related to seizure outcome at any review period.

CONCLUSIONS

A general increase in mood disturbance was evident after surgery, particularly in temporal resection patients at the 1-month review. Site of surgery and psychosocial adjustment showed significant associations with postoperative mood disturbance, supporting the role of both neurobiological and psychosocial factors in mood outcome.

Comparison between the results of the Symptom Checklist-90 in two different populations with temporal lobe epilepsy

We performed a prospective psychopathological analysis of two distinct populations with temporal lobe epilepsy (TLE), medically treated patients (n=18) and patients surgically treated for mesial temporal sclerosis (n=19), and compared the psychopathology in the surgical population pre- and postoperatively. The Symptom Checklist-90 (SCL-90) was administered to both groups, with the surgical patients being tested before and 6 months after surgery. A multivariant comparison of the SCL-90 subscales was made between medically treated patients and patients before and after surgical treatment. Surgically treated patients had less psychopathology after surgery than before. The comparison of surgically treated patients with medically treated patients showed statistically significant differences in most subscales. Except for the subscale of Hostility, no statistically significant differences were found between medically treated patients and the surgical population before lobectomy.