The cognitive profile of occipital lobe epilepsy and the selective association of left temporal lobe hypometabolism with verbal memory impairment

Abstract

SUMMARYWe investigated the cognitive profile of structural occipital lobe epilepsy (OLE) and whether verbal memory impairment is selectively associated with left temporal lobe hypometabolism on [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET). Nine patients with OLE, ages 8-29 years, completed presurgical neuropsychological assessment. Composite measures were calculated for intelligence quotient (IQ), speed, attention, verbal memory, nonverbal memory, and executive functioning. In addition, the Wisconsin Card Sorting Test (WCST) was used as a specific measure of frontal lobe functioning. Presurgical FDG-PET was analyzed with statistical parametric mapping in 8 patients relative to 16 healthy volunteers. Mild impairments were evident for IQ, speed, attention, and executive functioning. Four patients demonstrated moderate or severe verbal memory impairment. Temporal lobe hypometabolism was found in seven of eight patients. Poorer verbal memory was associated with left temporal lobe hypometabolism (p = 0.002), which was stronger (p = 0.03 and p = 0.005, respectively) than the association of left temporal lobe hypometabolism with executive functioning or with performance on the WCST. OLE is associated with widespread cognitive comorbidity, suggesting cortical dysfunction beyond the occipital lobe. Verbal memory impairment is selectively associated with left temporal lobe hypometabolism in OLE, supporting a link between neuropsychological dysfunction and remote hypometabolism in focal epilepsy.

Associations between the self-reported frequency of hearing chemical alarms in theater and regional brain volume in Gulf War Veterans

“…Two recent meta-analyses that examined data from nearly 2000 cases of low-level occupational OP exposures reported significant decrements in working memory, visual memory, attention, psychomotor speed, executive function, and visuospatial function relative to non-exposed controls (Ismail et al, 2012; Ross et al, 2013). Notably, these cognitive processes have been linked with integrity of the frontal (Alvarez and Emory, 2006; Beyer and Krishnan, 2002; Corbetta and Shulman, 2002; Ester et al, 2015; Kochunov et al, 2010), parietal (Corbetta and Shulman, 2002; Ester et al, 2015), and occipital (Knopman et al, 2014) cortex, where we found significant, inverse associations between GM volume and the frequency of hearing chemical alarms sound in theater.…”

Cognitive dysfunction in patients with epilepsy: focus on clinical variables

“…For example, juvenile myoclonic epilepsy seems to be characterized by executive dysfunction [5]; short-term visuospatial memory dysfunction, executive dysfunction and frontal lobe dysfunction have been reported for Unverricht-Lundborg disease [6,7]; language dysfunction has been reported in Landau-Kleffner syndrome [8]; and poor language acquisition and visuospatial defects have been reported in Dravet syndrome [9] and Rett syndrome [10]. Even supposedly 'benign' epilepsies, such as benign epilepsy of childhood with centrotemporal spikes [11] or benign occipital epilepsy [12], seem to be characterized by a specific pattern of cognitive dysfunction.…”

Neuroimaging of epilepsy

“…In patients with occipital-lobe epilepsy, poorer verbal memory and executive function were associated with left temporal lobe hypometabolism (Knopman et al, 2014). Left mesial temporal metabolism correlated with anterograde and retrograde memory in patients with transient epileptic amnesia (Mosbah et al, 2014).…”