Neuropsychological sequelae of head injury in a New Zealand adolescent sample

Inference comprehension of adolescents with traumatic brain injury: A working memory hypothesis

This study investigated inference comprehension performance in adolescents who had suffered a traumatic brain injury (TBI). Using stimuli adapted from Lehman-Blake and Tompkins, participants listened to short paragraphs that varied according to the working memory demands of the task and answered comprehension questions that required inferences to be generated. Six adolescents, aged 12-16 years, who had suffered a TBI prior to the age of 10 years, were assessed and their performance was compared to six individually age-matched peers with typical development. Analysis revealed that individuals with TBI did not differ from non-injured peers in their understanding of inferences when the storage demands of the task were minimized. However, when storage demands were high, adolescents with TBI performed poorly compared to their age-matched peers. Results are discussed relative to a working-memory hypothesis of impairment following TBI.

Memory deficits in abstinent MDMA (ecstasy) users: neuropsychological evidence of frontal dysfunction

Chronic administration of the common club drug 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) is associated with long-term depletion of serotonin (5-HT) and loss of 5-HT axons in the brains of rodents and non-human primates, and evidence suggests that recreational MDMA consumption may also affect the human serotonergic system. Moreover, it was consistently shown that abstinent MDMA users have memory deficits. Recently, it was supposed that these deficits are an expression of a temporal or rather hippocampal dysfunction caused by the serotonergic neurotoxicity of MDMA. The aim of this study is to examine the memory deficits of MDMA users neuropsychologically in order to evaluate the role of different brain regions. Nineteen male abstinent MDMA users, 19 male abstinent cannabis users and 19 male drug-naive control subjects were examined with a German version of the Rey Auditory Verbal Learning Test (RAVLT). MDMA users showed widespread and marked verbal memory deficits, compared to drug-naive controls as well as compared to cannabis users, whereas cannabis users did not differ from control subjects in their memory performance. MDMA users revealed impairments in learning, consolidation, recall and recognition. In addition, they also showed a worse recall consistency and strong retroactive interference whereby both measures were previously associated with frontal lobe function. There was a significant correlation between memory performance and the amount of MDMA taken. These results suggest that the memory deficits of MDMA users are not only the result of a temporal or hippocampal dysfunction, but also of a dysfunction of regions within the frontal cortex.