Functional independence within the self-memory system: new insights from two cases of developmental amnesia.

Neuropsychological and neuroimaging data suggest that the self-memory system can be fractionated into three functionally independent systems processing personal information at several levels of abstraction, including episodic memories of one's life (episodic autobiographical memory, EAM), semantic knowledge of facts about one's life (semantic autobiographical memory, SAM), and semantic knowledge of one's personality [conceptual self, (CS)]. Through the study of two developmental amnesic patients suffering of neonatal brain injuries, we explored how the different facets of the self-memory system develop when growing up with bilateral hippocampal atrophy. Neuropsychological evaluations showed that both of them suffered from dramatic episodic learning disability with no sense of recollection (Remember/Know procedure), whereas their semantic abilities differed, being completely preserved (Valentine) or not (Jocelyn). Magnetic resonance imaging, including quantitative volumetric measurements of the hippocampus and adjacent (entorhinal, perirhinal, and temporopolar) cortex, showed severe bilateral atrophy of the hippocampus in both patients, with additional atrophy of adjacent cortex in Jocelyn. Exploration of EAM and SAM according to lifetime periods covering the entire lifespan (TEMPAu task, Piolino et al., 2009) showed that both patients had marked impairments in EAM, as they lacked specificity, details and sense of recollection, whereas SAM was completely normal in Valentine, but impaired in Jocelyn. Finally, measures of patients' CS (Tennessee Self-Concept Scale, Fitts and Warren, 1996), checked by their mothers, were generally within normal range, but both patients showed a more positive self-concept than healthy controls. These two new cases support a modular account of the medial-temporal lobe with episodic memory and recollection depending on the hippocampus, and semantic memory and familiarity on adjacent cortices. Furthermore, they highlight developmental episodic and semantic functional independence within the self-memory system suggesting that SAM and CS may be acquired without episodic memories.

Academic achievement following childhood brain disease: implications for the concept of learning disabilities.

The present study examined three hypotheses regarding the consequences of early brain damage for academic achievement: First, early brain insults will have a negative impact on achievement, even in children with normal intelligence. Second, underachievement in these children will be at least partially independent of IQ (i.e., not fully accounted for by a lowering of IQ within the average range). Third, normally intelligent children with histories of brain insult will also manifest selective cognitive dysfunctions. To test these hypotheses, we compared two groups of children who had recovered from Haemophilus influenzae type b meningitis. The "complicated" group consisted of children who, as a consequence of having sustained neurologic complications during their illness, were more likely to have had brain insults. Children in the "uncomplicated" group did not have complications with their illness and were regarded as having escaped significant central nervous system (CNS) pathology. Only children with normal hearing and a prorated Full Scale IQ of at least 80 (WISC-R) were considered. Group differences on the Wide Range Achievement Test-Revised were consistent with the first two hypotheses. Although the two groups had similar Verbal IQs, the complicated group also had a lower mean Performance IQ and performed less well on perceptually demanding neuropsychological tasks. Findings suggest that learning disabilities may have selective, brain-related cognitive antecedents; but they challenge the practice of using IQ criteria for clinical diagnosis.

Adjunctive treatment with low-dose polymyxin B improves operant response rates and latency in infant rats with Haemophilus influenzae type b meningitis.

Polymyxin B given in conjunction with ampicillin protects infant rats against death from overwhelming Haemophilus influenzae type b infection. This study was undertaken to examine whether polymyxin B would mitigate the effects of brain damage caused by meningitis. Six- to 7-d-old Sprague-Dawley rats were infected subcutaneously into the nape with 10(7) cfu Haemophilus influenzae type b strain Eagan. This dose consistently caused bacteremia (1.2 X 10(5) cfu/mL) and meningitis (0.5 X 10(5) cfu/mL) in pilot studies. Twenty-four h after infection, all animals received intraperitoneal treatment consisting in either ampicillin alone (400 mg/kg X 4 q 3 h) repeated 12 h later, n = 15 or combined with polymyxin B (0.1 mg/kg/dose) n = 16. At age 2 mo, they were taken off ad libitum feeding and maintained at 80% of their wt. They were then conditioned to receive a food pellet by pressing a lever (continuous reinforcement). The next day, the time lapse between placement and pressing the lever for the first time was recorded (conditioned operant response or latency). Three wk later, the animals were put in the test chamber again and the time to press the lever (latency), as well as the time required to obtain 100 pellets (rate) were recorded. Animals who received polymyxin B had a significantly shorter reaction time; mean 34 s, SEM +/- 5.7 versus mean 88 s, SEM +/- 26.3, P less than or equal to 0.05 and performed significantly faster in obtaining 100 pellets; mean 925 s, SEM +/- 72.1 versus mean 1283 s, SEM +/- 126.3, p less than or equal to 0.02 (analysis of variance, Scheffé test).(ABSTRACT TRUNCATED AT 250 WORDS)

Follow-up of prospective randomized trial of ampicillin or chloramphenicol versus moxalactam treatment of Haemophilus influenzae type b meningitis.

In a prospective randomized trial, moxalactam administered to 66 children was compared with ampicillin or chloramphenicol given to 68 children for the treatment of Haemophilus influenzae type b meningitis. Acute morbidity and mortality rates were equivalent between the two treatment groups. At 2 years after discharge, the results of psychologic tests (Bayley Scales of Infant Development or McCarthy Scales of Children's Abilities) were also equivalent between the two treatment groups for patients remaining in the study.

Academic achievement in children ten to 12 years after Haemophilus influenzae meningitis.

Academic achievement by 23 children 10 to 12 years after treatment of Haemophilus influenzae meningitis was assessed using individually administered standardized tests, review of school transcripts, and parent and teacher questionnaires. The children's performance was compared with (1) their own performance in a previous study 6 to 8 years after the illness; (2) the performance of 23 similarly aged siblings in the previous study, a comparison which served to age match subjects and sibling controls; and (3) the performance of 11 of those similarly aged siblings retested in the current study. Subjects scored in the average range on all measures. Scores were comparable to results 4 years previous in four of six academic measures, with minor deterioration in reading single words and decoding nonsense words. There were no differences between subjects in the current study and control subjects from the previous study, except in decoding nonsense words, and no differences between subjects and control subjects in the current study, except in paragraph reading accuracy. Scholastic grade point averages and scores on parent and teacher behavior problem-rating scales showed no group differences. Subjects used more school-based remedial services, although the trend did not achieve statistical significance. Parents reported spending more time with subjects than with control subjects helping with homework. These findings suggest that children who have recovered from meningitis due to H influenzae can maintain scores and grades comparable to their siblings as they progress to middle school. Their academic success may involve more school and family support to compensate for the mild differences in intelligence quotient and neuropsychologic testing found in the previous study.

Intellectual, neuropsychological, and achievement outcomes in children six to eight years after recovery from Haemophilus influenzae meningitis.

Twenty-four grade school children who had sustained an earlier episode of Haemophilus influenzae type b meningitis were tested, along with a group of 24 school-aged siblings. Evaluations consisted of tests of IQ, academic achievement, and neuropsychological skills. Parents completed forms rating each child's behavioral adjustment and temperament. Available school-administered standardized achievement tests were also obtained. Information relating to the episode of meningitis was extracted from the medical charts of each child who had had meningitis in order to investigate the relationship of these parameters to developmental outcome. Results showed that, compared with nearest-age siblings, children who had had meningitis scored lower on performance IQ and full-scale IQ. The group that had had meningitis also performed more poorly on several neuropsychological tasks. However, the groups did not differ in verbal IQ, and they performed comparably on all academic measures. Significant behavioral adjustment problems were absent from both groups, and there were no notable differences in temperament. Although findings support the existence of postmeningitis sequelae, the selective nature of the deficiencies observed indicate that prognosis for children in the age range examined may be better than that suggested by earlier studies.

Long-term prognosis after H. influenzae meningitis: prospective evaluation.

A prospective, long-term evaluation was made of 22 children who had recovered from H. influenzae type B meningitis. At the time of the illness they had been either between two months and two years of age (Group A) or over four years of age (Group B), the purpose being to compare outcome in infants with that in older children. Two children, one in each group, had neurological or auditory sequelae. None of the others had neurological or auditory deficit, nor was there evidence of growth retardation. Fifteen of the children were tested psychometrically, using siblings as controls. Five had IQs between 70 and 90, but in all but one case their siblings had similar IQs. Five of seven children in Group B performed poorly on two items in the psychometric test, but so did their siblings. This study suggests that care is needed in selecting a control group with which to compare children being tested for psychomotor retardation after meningitis.