Traumatic brain injury (TBI) is frequently associated with both cognitive and behavioural executive dysfunction. Assessment of executive dysfunction has traditionally been measured using tests that were not based on theory and this has been postulated as one reason why there are poor predictive relationships between performance on traditional executive tasks and functional outcome following TBI. Baddeley�s (1996) working memory model may offer a theoretical basis with which to design new executive measures and possibly improve prediction of outcome. Baddeley�s theory has made recent advances in identifying core central executive (CE) processes that are likely to be relevant to TBI. The research presented in the thesis used Baddeley�s proposed coordinative sub function of the CE (and it related dual tasking measure) to assess: (a) whether this theoretically based dual tasking test would be sensitive to TBI injury status and show a significant relationship with functional outcome, (b) whether the theoretically based test would be more sensitive to the above relationships than executive measures that have been traditionally available, and (c) whether more ecologically relevant dual tasks could be developed that reflect the coordinative construct and improve predictive relationships between task performance and real life functional ability. This study found that Baddeley�s Dual Task Test (DTT) measure was sensitive to TBI injury and was related to functional outcome following injury. A questionnaire assessing everyday dual tasking ability was developed as was an in vivo conversation and motor based dual task. The dual tasking questionnaire reflected Baddeley�s coordinative construct, however, applications to an in vivo conversation and motor based dual task were less successful. These ecologically relevant tasks showed a relationship between language dysfluencies and dual tasking and identified avoidance of dual tasking in everyday settings as an important predictor of functional outcome following injury. Overall the DTT and the dual tasking questionnaire showed greater injury sensitivity and stronger relationships with outcome than three executive measures traditionally used in clinical practice. Regression analysis confirmed that the dual based tasks were helpful in predicting a variety of outcomes following TBI, and implications for rehabilitation planning are discussed. Further increases in the predictive power of the dual tasking construct are likely to be achieved when mechanisms of action involved in both laboratory-based and real-life dual tasking are identified. Findings from the current study suggest a range of mechanisms could be involved in dual tasks and these are discussed.

<p>This paper presents verbal working memory test results towards establishing the effects of menstrual cycle on working memory of women. The study comprised of a subject-set of twenty healthy young women with a regular 28 – 32 day menstrual cycles. Subjects were tested twice, once during their menstrual phase and second during their ovulation phase (on approximately day 12). Working memory tests were performed in a random sequence i.e. for some subjects during the menstrual phase (low estrogen level) working memory test occurred before their ovulation phase (high estrogen level) memory test and vice versa for other subjects. Study revealed that the test scores in the ovulatory phase were significantly higher than those in the menstrual phase. These findings suggest that higher levels of estrogen may improve working memory. Moreover, effects of estrogen on mood were also considered during both phases of menstruation. The fluctuation in estrogen levels seems to have an effect on women’s mood during menstrual and ovulation phases.</p>

<p>Previous research has shown both positive and negative effects of gaming on academic and cognitive performance. The purpose of this study was to assess the effect of gaming on development of working memory (WM), inattention, reading and math ability using a longitudinal design. A randomly chosen sample of 335 (168 girls) 6–25 year olds performed tests of visuo-spatial and verbal WM, reading and math ability twice, with a two year interval. Gaming and inattention were assed with questionnaires. Time spent gaming did not affect development of any of the variables. However, game category did correlate with development of visuo-spatial WM, with action-gamers having a more favourable development. There was, however, no positive interaction with more time spent gaming for action-gamers. These results suggest that gaming should not be regarded as a damaging leisure activity. There could instead be some positive effects of gaming, but future research should try to identify the aspects of gaming contributing to this effect.</p>

<p>Working memory (WM) is essential for our ability to function cognitively. In this thesis we set out to examine the effects of computerized WM training in adults, through a randomized, comparison group controlled and double blind design. We measured this using a neuropsychological test called Paced Auditory Serial Addition Task (PASAT), which measures executive functions. The participants (N106), divided into four groups, young (20-30), old (60-70) and training-low dose. They trained with a computerized WM training program called Rememo© at home for five days a week during a period of five weeks. Before and after training they took the test, and then again after three months. The training gave significant improvement on PASAT performance in both young and old, and that the effect was significant at follow up. In conclusion, WM training has an effect even outside the specific tasks trained, which gives strong support to the theory of generalization and also support findings of plasticity in the aging brain.</p>

<p> </p><p>Den socialt kompetente har hög social status, många vänner, ett funktionellt beteende och sociala förmågor så som empati och hjälpsamhet. Avsaknad av social kompetens innebär bland annat känslomässiga och beteendemässiga problem. I denna studie medverkade totalt 30 gymnasieelever som genomgick två arbetsminnestest samt fyllde i en självvärderingsenkät som mäter social kompetens. Syftet var att undersöka om det finns ett samband mellan en tonårings arbetsminne och sociala kompetens. Studien begränsades till att mäta arbetsminnets fonologiska och visuellspatiala lagringsenheter samt två sociala förmågor; prosocialt beteende och initiativtagande. Inga signifikanta korrelationer mellan arbetsminne och social kompetens kunde påvisas. Eventuellt kan de icke existerande korrelationerna bero på att fel del av arbetsminnet eller fel del av den social kompetens stod i fokus för studien.</p>

<p><p>Previous research has indicated that meaningful background speech affects individuals reading comprehension performance differently and that this difference is related to working memory capacity. But what mechanism in working memory that is involved is not well understood. The present study’s main purpose was to investigate if individual differences in susceptibility to effects of speech on reading comprehension are moderated by working memory capacity as measured by the number updating task and two different mechanisms within this construct; delayed suppression (i.e. the inhibition of information that once was task-relevant but no longer is) and immediate suppression (i.e. the inhibition of processed but irrelevant information, while withholding attention focused on the to-be-recalled task-relevant items). Forty participants performed a number updating task and a reading comprehension task in silence and with meaningful background speech. The results indicated that the immediate suppression mechanism moderates the effects of background speech on reading comprehension. Those who can’t handle the interference from the background speech let the task-irrelevant information interfere with the ongoing cognitive task and therefore are more likely to be distracted by the background speech while reading a text.</p></p>

<p>Deficits in higher order cognitive processes such as inhibitory control and working memory (WM), grouped under the term of executive function (EF), have been shown to constitute one important component of the complex neuropsychology of Attention Deficit Hyperactivity Disorder (ADHD). The aim of the present thesis was to examine EF in relation to ADHD, with primary focus on structure (i.e., dimensions) and developmental change. Rooted in the developmental and dimensional perspectives of ADHD, which propose that the disorder represents the extreme of or quantitative delays in traits that are present throughout the general population, four studies (I-IV) based on non-clinical and clinical samples of children at different developmental levels were conducted.</p><p>Together, the results from Study I-IV suggest that inhibitory control and WM are important components of EF in typically developing children as well as in relation to ADHD symptoms. Of particular interest are the findings from Study II, III, and IV, showing that inhibitory control and WM seem to be of different importance depending on the child’s age. More specifically, the non-clinical and clinical studies suggest that inhibitory control and WM are important in predicting ADHD symptoms, with deficits in inhibitory control primarily being associated with ADHD symptoms for preschool and younger elementary school-aged children, whereas deficits in WM are associated with ADHD symptoms for older elementary school-aged children. </p><p>In conclusion, the results of the present thesis are consistent with Barkley’s (1997) developmental prediction concerning the relation between EF and ADHD, which suggests that impaired inhibitory control is an early developmental precursor to or a factor that “sets the stage” for deficits in more complex EFs such as WM. The home taking message from the present thesis is that age matters not only in the behavioral, but also in the neuropsychological manifestation of ADHD. To our knowledge, these findings are among the first to show that age is an important factor that should be taken into account in future ADHD research, theory, and treatment.</p>

Current theoretical models of ADHD (i.e., Disinhibition Model: Barkley, 1997; Working Memory Model: Rapport et al., 2001) conceptualize ADHD as the disorder of executive function (EF) with some variation in their emphases on particular components of the broadly-defined EF (e.g., working memory vs. inhibition) and in their postulated relationships with ADHD symptoms. Although these models provide systematic accounts of the manifestation of ADHD, they have not been extensively tested from an empirical standpoint. Moreover, despite the fact that ADHD is highly comorbid with other additional conditions such as learning and behavioral problems and EF deficits are found in individuals with these conditions as well as in those with ADHD, current EF models have not specified the developmental relationship between ADHD and its comorbid conditions. This study was: (1) to examine the extent to which two current models of ADHD are supported in a sample of 102 adults; (2) to present an ??integrated?? model by combining two current models of ADHD and linking them to recent research findings on two common comorbid conditions with ADHD (i.e., reading difficulty and substance abuse); and (3) to test and revise such an integrated model in the light of data using a latent variable analysis. Major findings provided a strong support for the Working Memory Model with a lesser degree of support for the Disinhibition Model. Preliminary evidence of working memory as the primary deficit in ADHD was also obtained in the present sample. Finally, the integrated EF model and its revised model (final model) demonstrated a very good fit to the data. These findings suggest that the integrated model provides a unified account of how EF deficits contribute to the manifestation of ADHD symptoms and comorbid conditions with ADHD. Given some limitations (e.g., sample size and scope) of the present study, current findings need to be replicated.

In dieser Arbeit wird in mehreren Experimenten untersucht, wie gut junge und alte Erwachsene Sätze mit unterschiedlich komplexer syntaktischer Struktur verstehen können. Zentrales Thema dabei sind die Schwierigkeiten, die ältere Erwachsene mit der Objekt-vor-Subjekt-Wortstellung haben. Untersucht wird, inwiefern diese beobachteten Altersunterschiede durch eine reduzierte verbale Arbeitsgedächtniskapazität der älteren Erwachsenen erklärt werden können. Dabei stellt sich die Frage, ob die Defizite ein generelles verbales Arbeitsgedächtnis betreffen oder ob es ein eigenes Verarbeitungs-system für syntaktische Informationen gibt, dessen Kapazität mit dem Alter abnimmt. Es wurde versucht, die postulierte reduzierte Arbeitsgedächtniskapazität der älteren Erwachsenen an jungen Erwachsenen zu simulieren, indem deren Arbeitsgedächtniska-pazität durch eine Zusatzaufgabe künstlich eingeschränkt wurde. Weiterhin wurden die Altersunterschiede bei syntaktisch komplexen zentraleingebetteten Relativsätzen mit denen bei syntaktisch einfacheren koordinierten Hauptsätzen verglichen. Um die Studienteilnehmer mit den seltenen objektinitialen Strukturen zu konfrontieren und ihre Erfahrung mit solchen Sätzen zu verändern, wurden schließlich sowohl junge als auch alte Erwachsene mit Sätzen mit Objekt-vor-Subjekt-Wortstellung trainiert. / In this paper several experiments about age differences in comprehension of sentences with different syntactical structure are reported. The main focus is on the difficulties old adults experience when a sentence starts with an object. Can the age differences be explained by differences in working memory capacity? Have old adults less working memory capacity, or does there exist a separate working memory for syntactic information which declines with age? In an age simulation, young adults working memory capacity was reduced by an additional digit load. Age differences in comprehension of syntactical complex sentences were compared with age differences in sentences with less complex syntactical structure. To change their experience with the rare object initial word order participants were trained with object initial sentences.

Deficits in higher order cognitive processes such as inhibitory control and working memory (WM), grouped under the term of executive function (EF), have been shown to constitute one important component of the complex neuropsychology of Attention Deficit Hyperactivity Disorder (ADHD). The aim of the present thesis was to examine EF in relation to ADHD, with primary focus on structure (i.e., dimensions) and developmental change. Rooted in the developmental and dimensional perspectives of ADHD, which propose that the disorder represents the extreme of or quantitative delays in traits that are present throughout the general population, four studies (I-IV) based on non-clinical and clinical samples of children at different developmental levels were conducted. Together, the results from Study I-IV suggest that inhibitory control and WM are important components of EF in typically developing children as well as in relation to ADHD symptoms. Of particular interest are the findings from Study II, III, and IV, showing that inhibitory control and WM seem to be of different importance depending on the child’s age. More specifically, the non-clinical and clinical studies suggest that inhibitory control and WM are important in predicting ADHD symptoms, with deficits in inhibitory control primarily being associated with ADHD symptoms for preschool and younger elementary school-aged children, whereas deficits in WM are associated with ADHD symptoms for older elementary school-aged children. In conclusion, the results of the present thesis are consistent with Barkley’s (1997) developmental prediction concerning the relation between EF and ADHD, which suggests that impaired inhibitory control is an early developmental precursor to or a factor that “sets the stage” for deficits in more complex EFs such as WM. The home taking message from the present thesis is that age matters not only in the behavioral, but also in the neuropsychological manifestation of ADHD. To our knowledge, these findings are among the first to show that age is an important factor that should be taken into account in future ADHD research, theory, and treatment.