Contribution of autobiographic memory impairment to subjective memory complaints in focal epilepsy.

"My memory is terrible!" is a common refrain among people with epilepsy, but such complaints are not reliably linked to poor performances on standard tests of memory. Negative affect like depression and anxiety are the most robust predictor of these complaints; however, neither do they entirely account for the phenomenon. The contribution of autobiographic memory impairment to subjective memory complaints in focal epilepsy has not been well-explored despite autobiographic memory impairments being common in patients with epilepsy, and the face validity of relating day-to-day memory failings to such a personally relevant form of memory. The current study sought to clarify whether autobiographic memory dysfunction contributes to subjective complaints in epilepsy, above and beyond negative affect, objective memory impairment, and epileptological factors in a large sample of patients with drug-resistant focal epilepsy relative to healthy controls (N = 135). Patients were stratified into groups with mesial temporal (MT; n = 40) versus nonmesial temporal (NMT; n = 46) foci. Compared to controls (n = 46), both patient groups reported more bitter subjective memory complaints (p < 0.001, large effect size), demonstrated poorer episodic (p = 0.001, large effect size) and semantic autobiographical recall (p = 0.004, medium effect size), and had higher levels of depressive symptomatology (p = 0.011, medium effect size), and trait neuroticism (p = 0.015, medium effect size). Contrary to expectations, multiple regression analyses revealed that autobiographic memory function was not an independent predictor of subjective memory complaints in either group with epilepsy. In people with epilepsy with MT foci, objective verbal memory dysfunction, neuroticism, and female gender predicted memory complaints (R2 = 0.70, p = 0.015), whereas only neuroticism predicted memory complaints in people with epilepsy with NMT foci (R2 = 0.21, p = 0.001). Although patients' poor recall of their autobiographical memories did not contribute to their concerns about their day-to-day memory function, the findings indicate that the location of the epileptogenic focus can provide clues as to the underlying contributors to subjective memory complaints in focal epilepsy. Important clinical implications to stem from these findings include the need for clinicians to adopt a patient-tailored, multifactorial lens when managing memory complaints in people with epilepsy, taking into account both psychological and cognitive factors.

Altered self-identity and autobiographical memory in epilepsy.

OBJECTIVE: Research suggests that individuals with chronic epilepsy display differences in their self-identity. The mechanisms by which self-identity is altered, however, are not well understood. Neural networks supporting autobiographical memory retrieval in the mesial temporal (MT) lobe are thought to be fundamental to self-identity processes. Thus, we examined differences in self-identity and autobiographical memory in patients with either MT or non-mesial temporal (NMT) foci with early or late age of habitual seizure onset. METHODS: Participants included 102 adults: 51 healthy individuals and 51 patients with drug-resistant focal seizures (19 MT, 32 NMT). We used the Ego Identity Process Questionnaire to profile the identity development of participants, and examined how this related to memory function assessed using the Autobiographical Memory Test. RESULTS: Patients and controls had strikingly different self-identity profiles, with early onset MT patients showing the least identity development compared to controls and other patient groups. In contrast, late-onset NMT patients showed the highest level of identity development of the patient groups and closely resembled healthy controls (p < 0.05 for all comparisons). For all MT patients, poor autobiographical memory retrieval was correlated with altered self-identity (p < 0.001). No associations between autobiographical memory and self-identity were evident in the NMT group. SIGNIFICANCE: Self-identity in epilepsy may be modulated by the extent to which seizure foci impinge on the autobiographical memory network and the timing of seizure onset. Early disruption to MT regions of the autobiographical memory network may constitute a neurocognitive mechanism by which self-identity is altered in chronic focal epilepsy.