Moderate-to-large weighted effect sizes were found for all cognitive domains suggesting that long-term benzodiazepine users were significantly impaired, compared with controls, in all of the areas that were assessed. However, this study has several limitations, one being that it includes a relatively small number of studies. Further studies need to be conducted; ideally, well designed, controlled studies that thoroughly investigate certain areas of cognitive functioning and present data in such a way so as to be amenable to inclusion in a meta-analysis. Incorporating the information from these studies into a larger meta-analysis would allow for a more thorough and statistically sound investigation of the effects of moderator variables. The observation that long-term benzodiazepine use leads to a generalised effect on cognition has numerous implications for the informed and responsible prescription of these drugs.

The sulci and gyri found within the anterior cingulate (AC), and across the cerebrum generally, have been found to vary in location and complexity from one individual to the next, making it difficult to analyze imaging data accurately and systematically. In this study, we examined the nature of morphometric variance in the AC of the left and right cerebral hemispheres using high-resolution structural magnetic resonance imaging (MRI) acquired from 176 healthy volunteers. Depending on the presence of a paracingulate sulcus (PCS) and its antero-posterior extent, three types of AC patterns were identified: 'prominent', 'present' and 'absent'. Hemispheric comparisons across the whole sample showed the PCS to be more commonly 'prominent' in the left hemisphere and more commonly 'absent' in the right hemisphere. There was a significant gender difference, such that males showed an asymmetric pattern characterized by increased fissurization of the left AC, while females showed greater symmetry, with less fissurization of the left AC. Overall cerebral morphology, namely hemispheric volume and hemispheric fissurization, were also measured and used as independent variables as well as covariates in the analyses in order to ascertain the specificity of the results regarding AC morphology. Results showed that cerebral volume for males was larger on the right than on the left while fissurization showed the reverse asymmetry of greater leftward fissurization. In contrast, females were symmetric in both respects. The findings regarding AC morphology could not be explained by differences in these overall cerebral measures or by differences in age and handedness within the population. The results suggest that in the normal male brain, there exist morphological asymmetries at both the global and local levels that are less apparent in the female brain. The findings have implications for future studies examining the organization, development and functional anatomy of the AC.

Despite the widespread prescribing of benzodiazepines, uncertainty still surrounds the potential for cognitive impairment following their long-term use. Furthermore, the degree of recovery that may take place after withdrawal or the level of residual impairment, if any, that is maintained in long-term benzodiazepine users is also unclear. The current paper employed meta-analytic techniques to address two questions: (1) Does the cognitive function of long-term benzodiazepine users improve following withdrawal? (2) Are previous long-term benzodiazepine users still impaired at follow-up compared to controls or normative data? Results of the meta-analyses indicated that long-term benzodiazepine users do show recovery of function in many areas after withdrawal. However, there remains a significant impairment in most areas of cognition in comparison to controls or normative data. The findings of this study highlight the problems associated with long-term benzodiazepine therapy and suggest that previous benzodiazepine users would be likely to experience the benefit of improved cognitive functioning after withdrawal. However, the reviewed data did not support full restitution of function, at least in the first 6 months following cessation and suggest that there may be some permanent deficits or deficits that take longer than 6 months to completely recover.

Ninety-eight undergraduate students were subjected to the TMT as well as a series of derived measures from the TMT with a view to ascertaining the nature of the contribution of each to the performance. Performance on the TMT(A) was uniquely contributed to by visual search and motor speed measures, whereas the performance on TMT(B) was uniquely contributed to by the visual search and cognitive alternation measures. After controlling for the effects of TMT(A) on TMT(B), further variance in the score on TMT(B) was contributed to, in order of effect, by lowered reading level, poor skill in visual search, poor ability to mentally maintain two simultaneous sequences, as well as decrease in attention and working memory functions. The analysis indicates that, in a nonclinical sample, the TMT measures a number of different functions and the observation of impaired performance must be further investigated to ascertain the specific nature of these deficits in order to guide rehabilitation and management planning.

Participants were asked to generate as many words as possible using large and small category sizes with the initial letter and semantic category search strategies. The production of each participant for each 15-s time slice on each task was recorded. The results revealed that on all fluency tasks, the production in the initial time slice was highest and also of greatest frequency. As time on task increased the production decreased, as did the word frequency of the items produced. The results are consistent with the notion that there is a store of high-frequency words accessed during the early trials of the fluency tasks and as this store becomes exhausted the production and the word frequency decreases.