Recognition memory is impaired in children after prolonged febrile seizures

Abstract

Children with a history of a prolonged febrile seizure show signs of acute hippocampal injury on magnetic resonance imaging. In addition, animal studies have shown that adult rats who suffered febrile seizures during development reveal memory impairments. Together, these lines of evidence suggest that memory impairments related to hippocampal injury may be evident in human children after prolonged febrile seizures. The current study addressed this question by investigating memory abilities in 26 children soon after a prolonged febrile seizure (median: 37.5 days) and compared their results to those of 37 normally developing children. Fifteen patients were reassessed at a mean of 12.5 months after their first assessment to determine the transiency of any observed effects. We used the visual paired comparison task to test memory abilities in our group, as this task does not depend on verbal abilities and also because successful performance on the task has been proven to depend on the presence of functional hippocampi. Our findings show that patients perform as well as controls in the absence of a delay between the learning phase and the memory test, suggesting that both groups are able to form representations of the presented stimulus. However, after a 5-min delay, patients' recognition memory is not different from chance, and comparison of patients and controls points to an accelerated forgetting rate in the prolonged febrile seizure group. The patients' performance was not related to the time elapsed from the acute event or the duration of the prolonged febrile seizure, suggesting that the observed effect is not a by-product of the seizure itself or a delayed effect of medication administered to terminate the seizure. By contrast, performance was related to hippocampal size; participants with the smallest mean hippocampal volumes revealed the biggest drop in performance from the immediate to the delayed paradigm. At follow-up, children were still showing deficiencies in recognizing a face after a 5-min delay. Similarly, this suggests that the observed memory impairments are not a transient effect of the prolonged febrile seizures. This is the first report of such impairments in humans, and it is clinically significant given the links between mesial temporal sclerosis and prolonged febrile seizures. The persistence of these impairments a year onwards signals the potential benefits of intervention in these children who run the risk of developing episodic memory deficits in later childhood.

Triple therapy with pyridoxine, arginine supplementation and dietary lysine restriction in pyridoxine-dependent epilepsy: Neurodevelopmental outcome

“…The radiological findings are similar in appearance to those seen in white matter injury of the premature and neonatal infant, and reflect acute brain disturbances occurring immediately prior to therapy, and can be directly related to the neurological sequelae observed. Subjects 2 and 5 had mesial temporal sclerosis with hippocampal injury, and both subjects had memory and concentration impairments [42,43]. Hippocampal sclerosis is most commonly associated with chronic epilepsy and has been associated with temporal lobe epilepsy and a history of febrile seizures [44,45], although it has been infrequently reported in subjects with PDE [41].…”

Febrile seizures:

“…This suggests that memory impairments are not a transient effect of prolonged febrile seizures. 63 These studies show that the outcome of simple febrile seizures is generally benign, but in children with recurrent or prolonged febrile seizures this may not be the case. Parents should be cautioned about this so that appropriate developmental support is in place should it be required.…”

“…[61][62][63] They need advice on the common nature of febrile seizures, the rare association with epilepsy, and reassurance that the tendency diminishes with age as the brain matures. Given the 1 in 3 risk of recurrence, it is important to advise parents on what to do if further febrile seizures occur at home (box 3).…”

Proinflammatory and anti-inflammatory cytokines in febrile seizures and epilepsy: systematic review and meta-analysis

“…FS, the most common type of epileptic seizures in early life world wide (Nakayama and Arinami, 2006;Kundu et al, 2012;Salzmann et al, 2012), is a matter of concern to pediatricians with a total prevalence of 3%-7% in children up to 7 years (Cross, 2012) and a cumulative incidence of 2%-5% in the first 5 years of life (Verity et al, 1985;Visser et al, 2012). FS, occurring during rapid rising of fever (Özaydın et al, 2012) between 6 months and 5 years of age (Klein et al, 2012;Kumari et al, 2012;Martinos et al, 2012;Teran et al, 2012;Zareifar et al, 2012), can be divided into simple forms (only occuring once in 24 h, generalized, and duration < 15 min) and complex forms (recurrent during 24 h, focal, and duration > 15 min) (Kira et al, 2005;Abdel Rasol et al, 2012;French, 2012;Offringa and Newton, 2013;Sasidaran et al, 2012;Scott et al, 2012;Yu et al, 2012).…”