Behavioral profiles in frontal lobe epilepsy: Autobiographic memory versus mood impairment

ObjectivesAutobiographic memory encompasses the encoding and retrieval of episodes, people, and places encountered in everyday life. It can be impaired in both epilepsy and frontal lobe damage. Here, we performed an initial investigation of how autobiographic memory is impacted by chronic frontal lobe epilepsy (FLE) together with its underlying pathology. MethodWe prospectively studied a series of nine consecutive patients with medically refractory FLE, relative to 24 matched healthy controls. Seven of the nine patients had frontal lobe structural abnormalities. Episodic and semantic autobiographic memory functioning was profiled, and factors associated with impaired autobiographic memory were identified among epileptologic, neuroimaging, neuropsychiatric, and cognitive variables including auditory-verbal and visual memory, and the executive function of cognitive control. ResultsResults showed that the FLE group experienced significantly higher rates of autobiographic memory and mood disturbance (p<0.001), with detailed assessment of individual patients revealing two profiles of impairment, primarily characterized by cognitive or mood disturbance. Five of the patients (56%) exhibited significant episodic autobiographic memory deficits, whereas in three of these, knowledge of semantic autobiographic facts was preserved. Four of them also had reduced cognitive control. Mood disorder was largely unrelated to poor autobiographic memory. In contrast, the four cases with preserved autobiographic memory were notable for their past or current depressive symptoms. SignificanceThese findings provide preliminary data that frontal lobe seizure activity with its underlying pathology may selectively disrupt large-scale cognitive or affective networks, giving rise to different neurobehavioral profiles that may be used to inform clinical management.