Differential contributions of objective memory and mood to subjective memory complaints in refractory focal epilepsy

People with epilepsy frequently present with bitter memory complaints. Previous research variously attributes this to symptoms of mood disturbance or objective memory deficits. To investigate the influence of the epileptogenic region on this variability, we examined interrelationships between mood, objective memory, and memory complaints in a sample of patients with refractory focal epilepsy and controls (N = 96). Patients had either mesial temporal (MT, n = 39) or non mesial-temporal (NMT, n = 21) foci. In contrast to controls (n = 36), both patient groups were highly concerned about their memory (P < 0.001) and were more likely to have a history of depression (P = 0.005). Multiple regression showed that objective memory dysfunction and current depressive symptoms predicted the memory complaints of patients with MT epilepsy (P = 0.005), whereas a history of depression predicted the complaints of patients with NMT epilepsy (P = 0.008). These findings suggest that patients have concerns about their memory underpinned by distinct psychological and neurobiological factors depending on the location of their epileptogenic focus.

Research Highlights
► Patients with focal seizures complain bitterly about their memory functioning.
► Subjective memory complaints may be differentially underpinned by mood and memory disturbance, depending on the location of the epileptogenic focus.
► The subjective memory complaints of patients with a mesial temporal focus are predicted by objective memory dysfunction and current symptoms of depression.
► The subjective memory complaints of patients with a focus outside this region are predicted by a history of depression.