Mild developmental dyslexia in university students: diagnosis and performance features in L1, L2, and L3

Avhandling visar att lindrig dyslexi påverkar läs- och skrivprestationer hos högpresterare. Särdrag träder tydligast fram i främmande språk och vid hantering av språkljud i krävande testuppgifter. Även om dyslexirelaterade problem vanligtvis är lindriga hos universitetsstudenter, är det centralt att dessa identifieras, eftersom de ses påverka akademiska prestationer. Avhandlingen lägger fram det första finlandssvenska dyslexitestet normerat för universitetsnivå (FS-DUVAN) och ger verktyg för utredning av läs- och skrivsvårigheter hos unga vuxna i Svenskfinland. Avhandlingen utforskar också språkspecifika särdrag av dyslexi hos högpresterande finlandssvenska universitetsstudenter i läs- och skrivuppgifter i svenska, finska och engelska. Detaljerade felanalyser visar att studenter med dyslexi speciellt har problem med kopplingar mellan språkljud och bokstav i det främmande språket engelska, som också i detta avseende är komplext. Resultat i komplexa kognitiva testuppgifter som förutsätter hantering av språkljud pekar på svikt i fonologisk processering, som betecknas som den huvudsakliga underliggande kognitiva nedsättningen vid utvecklingsbetingad dyslexi.

Effects of vapour pressure deficit and soil water content on leaf water potential between selected provenances of Eucalyptus microtheca in an irrigated plantation, eastern Kenya

Summary

Neurofilament proteins in the postnatal rat hippocampus. Developmental expression and changes in experimental epilepsy

Neurofilament proteins (NFs) are the major components of the intermediate filaments of the neuronal cytoskeleton. The three different NF proteins; the low (NF-L), medium (NF-M),and dendrites.NF proteins play an important role in neuronal development, and plasticity,and seem to contribute to the pathophysiology of several diseases. However, the detailed expression patterns of NF proteins in the course of postnatal aturation, and in response to seizures in the rat have remained unknown. In this work, I have studied the developmental expression and cellular distribution of the three NF proteins in the rat hippocampus during the postnatal development. The reactivity of NF proteins in response to kainic acid (KA)-induced status epilepticus (SE)was studied in the hippocampus of 9-day-old rats, and using in vitro organotypic hippocampal slices cultures prepared from P6-7 rats. The results showed that NF-L and NF-M proteins are expressed already at the postnatal day 1, while the expression of NF-H mainly occurred during the second postnatal week. The immunoreactivity of NF proteins varied depending on the cell type and sub-cellular location in the hippocampus. In adult rats, KA-induced SE typically results in severe and permanent NF degradation. However, in our P9 rats KA-induced SE resulted in a transient increase in the expression of NF proteins during the first few hours but not degradation. No neuronal death or mossy fiber sprouting was observed at any time after SE. The in vitro studies with OHCs, which mimick the in vivo developing models where a local injection of KA is applied(e.g. intrahippocampal), indicated that NF proteins were rapidly degraded in response to KA treatment, this effect being effectively inhibited by the treatment with the AMPA receptor antagonist CNQX, and calpain inhibitor MDL-28170. These compounds also significantly ameliorated the KA-induced region-specific neuronal damage. The NMDA receptor antagonist and the L-type Ca2+ channel blocker did not have any significant effect. In conclusion, the results indicate that the developmental expression of NF in the rat hippocampus is differentially regulated and targeted in the different hippocampal cell types during the postnatal development. Furthermore, despite SE, the mechanisms leading to NF degradation and neuronal death are not activated in P9 rats unlike in adults. The reason for this remains unknown. The results in organotypic hippocampal cultures confirm the validity of this in vitro model to study development processes, and to perform pharmacological studies. The results also suggest that calpain proteases as interesting pharmacological targets to reduce neuronal damage after acute excitotoxic insults.

“IT’S ALL RIGHT”. Multimodal rightward spatial bias modified by age and praxis

The general goal of the present work was to study whether spatial perceptual asymmetry initially observed in linguistic dichotic listening studies is related to the linguistic nature of the stimuli and/or is modality-specific, as well as to investigate whether the spatial perceptual/attentional asymmetry changes as a function of age and sensory deficit via praxis. Several dichotic listening studies with linguistic stimuli have shown that the inherent perceptual right ear advantage (REA), which presumably results from the left lateralized linguistic functions (bottom-up processes), can be modified with executive functions (top-down control). Executive functions mature slowly during childhood, are well developed in adulthood, and decline as a function of ageing. In Study I, the purpose was to investigate with a cross-sectional experiment from a lifespan perspective the age-related changes in top-down control of REA for linguistic stimuli in dichotic listening with a forced-attention paradigm (DL). In Study II, the aim was to determine whether the REA is linguistic-stimulus-specific or not, and whether the lifespan changes in perceptual asymmetry observed in dichotic listening would exist also in auditory spatial attention tasks that put load on attentional control. In Study III, using visual spatial attention tasks, mimicking the auditory tasks applied in Study II, it was investigated whether or not the stimulus-non-specific rightward spatial bias found in auditory modality is a multimodal phenomenon. Finally, as it has been suggested that the absence of visual input in blind participants leads to improved auditory spatial perceptual and cognitive skills, the aim in Study IV was to determine, whether blindness modifies the ear advantage in DL. Altogether 180-190 right-handed participants between 5 and 79 years of age were studied in Studies I to III, and in Study IV the performance of 14 blind individuals was compared with that of 129 normally sighted individuals. The results showed that only rightward spatial bias was observed in tasks with intensive attentional load, independent of the type of stimuli (linguistic vs. non-linguistic) or the modality (auditory vs. visual). This multimodal rightward spatial bias probably results from a complex interaction of asymmetrical perceptual, attentional, and/or motor mechanisms. Most importantly, the strength of the rightward spatial bias changed as a function of age and augmented praxis due to sensory deficit. The efficiency of the performance in spatial attention tasks and the ability to overcome the rightward spatial bias increased during childhood, was at its best in young adulthood, and decreased as a function of ageing. Between the ages of 5 and 11 years probably at first develops movement and impulse control, followed by the gradual development of abilities to inhibit distractions and disengage attention. The errors especially in bilateral stimulus conditions suggest that a mild phenomenon resembling extinction can be observed throughout the lifespan, but especially the ability to distribute attention to multiple targets simultaneously decreases in the course of ageing. Blindness enhances the processing of auditory bilateral linguistic stimuli, the ability to overcome a stimulus-driven laterality effect related to speech sound perception, and the ability to direct attention to an appropriate spatial location. It was concluded that the ability to voluntarily suppress and inhibit the multimodal rightward spatial bias changes as a function of age and praxis due to sensory deficit and probably reflects the developmental level of executive functions.

International adoption: Symptoms of attachment disorders and their associations with the child’s background and developmental outcome

Many internationally adopted children have lived their first years of life in an environment with limited opportunities for primary caregiving. The lack of consistent care increases the prevalence of attachment disorders among them. Less is known about the influences of attachment disorders on a child’s later course of life. This study is part of the Finnish Adoption Study. Parents of all Finnish children who had been internationally adopted by legal adoption organisations between 1985 and 2007 were sent questionnaires (N=1450). Parental evaluations of the children’s symptoms of reactive attachment disorder (RAD) at the time of adoption, their later learning or language problems using a screening scale, and children’s self-reported school bullying experiences were evaluated. Each child’s attachment-related behavioural problems were requested in a follow-up survey 1.9 and 3.8 years after adoption and compared with a Finnish reference group. This study indicated that Finnish internationally adopted children have at least three-fold prevalence of learning and language problems compared with their age-mates. A child’s symptoms of attachment disorders were associated with learning or language problems at school age as well as with his/her school bullying experiences. The adopted children had more attachment-related behavioural problems two years after adoption than their age-mates, but the difference was no longer evident four years after adoption. In conclusion, this study showed that the symptoms of attachment disorder indicate a risk for an adopted child’s later developmental outcome. The findings demonstrate the need for comprehensive clinical examinations and planning of treatment strategies for children with symptoms of RAD.