ABSTRACT
OBJECTIVE: The aim of the present study was to investigate whether working memory is impaired in mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS), a controversial and largely unexplored matter. METHODS: Twenty subjects with left MTLE-HS, 19 with right MTLE-HS, and 21 control right-handed subjects underwent neuropsychological assessment of episodic and semantic memory, executive functions, and specific working memory components. RESULTS: Left and right epileptogenic foci resulted in impairment of verbal and nonverbal episodic memory (verbal memory deficit greater in left MTLE-HS than in right MTLE-HS). In addition, patients with left MTLE-HS were impaired in learning paired associates, verbal fluency, and Trail Making. No differences were seen in the tests carried out to evaluate the working memory components (except visuospatial short-term memory in right MTLE-HS). CONCLUSION: In this study we did not detect reliable working memory impairment in patients with MTLE-HS with either a left or right focus in most tasks considered as tests of working memory components.
Subject(s)
Epilepsy, Temporal Lobe/complications , Functional Laterality/physiology , Hippocampus/pathology , Memory Disorders/etiology , Memory, Short-Term/physiology , Adult , Association Learning/physiology , Executive Function/physiology , Female , Humans , Male , Middle Aged , Neuropsychological Tests , Sclerosis/etiology , Statistics, Nonparametric , Verbal LearningABSTRACT
OBJECTIVE: The aim of the study described here was to examine the relationship between memory function, proton magnetic resonance spectroscopy ((1)H-MRS) abnormalities, and interictal epileptiform discharge (IED) lateralization in patients with temporal lobe epilepsy (TLE) related to unilateral mesial temporal sclerosis. METHODS: We assessed performance on tests of memory function and intelligence quotient (IQ) in 29 right-handed outpatients and 24 controls. IEDs were assessed on 30-minute-awake and 30-minute-sleep EEG samples. Patients had (1)H-MRS at 1.5 T. RESULTS: There was a negative correlation between IQ (P=0.031) and Rey Auditory Verbal Learning Test results (P=0.022) and epilepsy duration; between(1)H-MRS findings and epilepsy duration (P=0.027); and between N-acetylaspartate (NAA) levels and IEDs (P=0.006) in contralateral mesial temporal structures in the left MTS group. (1)H-MRS findings, IEDs, and verbal function were correlated. CONCLUSIONS: These findings suggest that IEDs and NAA/(Cho+Cr) ratios reflecting neural metabolism are closely related to verbal memory function in mesial temporal sclerosis. Higher interictal activity on the EEG was associated with a decline in total NAA in contralateral mesial temporal structures.
