Effects on cognitive performance of modulating the postprandial blood glucose profile at breakfast.

BACKGROUND/OBJECTIVES: Considering the importance of glucose as a brain substrate, the postprandial rate of glucose delivery to the blood could be expected to affect cognitive functions. The purpose was to evaluate to what extent the rate of glucose absorption affected measures of cognitive performance in the postprandial period. In addition, cognitive performance was evaluated in relation to individual glucoregulation. SUBJECTS/METHODS: A white wheat bread (WWB) enriched with guar gum (G-WWB) with the capacity to produce a low but sustained blood glucose net increment was developed. The G-WWB was evaluated in the postprandial period after breakfast with respect to effects on cognitive function (working memory and selective attention (SA)) in 40 healthy adults (49-71 years, body mass index 20-29 kg/m(2)), using a high glycaemic index WWB for comparison in a randomised crossover design. RESULTS: The G-WWB improved outcome in the cognitive tests (SA test) in the later postprandial period (75-225 min) in comparison with the WWB (P<0.01). Subjects with better glucoregulation performed superior in cognitive tests compared with subjects with worse glucoregulation (P<0.05). CONCLUSIONS: Beneficial effects on cognitive performance were observed with the G-WWB in the late postprandial period. The positive effect is suggested to emanate from improved insulin sensitivity, possibly in a combination with an enhanced neural energy supply. The results highlight the importance of carbohydrate foods that induces a low but sustained blood glucose profile in enhancing postprandial cognitive functions.

Effects of differences in postprandial glycaemia on cognitive functions in healthy middle-aged subjects.

OBJECTIVE: To find useful methods for the studies of cognitive function during a postprandial period, and to use these methods to evaluate function after test meals differing in post meal glycaemia. SUBJECTS/METHODS: Forty healthy volunteers aged 49-70 years were studied. A glucose solution (glucose 50 g) was provided through either a bolus or sipping regimen at breakfast to simulate a high-GI or a low-GI breakfast, respectively. Cognitive tests of working memory (WM) were performed at 35, 90, 120 and 150 min after commencing the breakfast, and a test of selective attention (SA) was performed at 170 min. RESULTS: Subjects with higher glucose tolerance performed better in the cognitive tests (P<0.05). After entering glucose tolerance as covariate, the subjects performed better in the working memory test at 90 min (P<0.034) and in the selective attention test at 170 min (P<0.017) after the simulated low-glycaemic index (GI) breakfast compared with the simulated high-GI breakfast. CONCLUSION: Possibly, the cognitive functions tested were enhanced by avoiding a sharp decline in blood glucose concentration and by maintaining a higher glycaemia in the late postprandial period, respectively. A low-GI diet is preferable in the prevention of the risk of cognitive decline as a result of less efficient glucose regulation.

Assessment and evaluation of individual prerequisites for dental education.

Since 2001 the School of Dentistry of Malmo University in Sweden has used an alternative admissions procedure based on results of an investigation supported by the Swedish Council for the Renewal of Undergraduate Education. The investigation concerned possibilities of predicting dental school performance on the basis of an interview, as well as tests of general intelligence, spatial ability, manual dexterity, empathy and social competence. Two groups of incoming students were followed from start to completion of their training. Significant relationships were found between (i) number of course examinations failed and poor results on interviews, as well as low scores on intelligence, spatial ability, and a test of spatial-manual ability, (ii) good results in a pre-clinical course in cavity preparation and high scores on spatial ability, (iii) assessments of high social competence during training and good results on interviews, as well as high scores on empathy and non-verbal intelligence. Dropout from the study programme could not be predicted, possibly due to the varying reasons for it.

Identifying children at risk for language impairment: screening of communication at 18 months.

AIM: To investigate the possibility of identifying children at risk for language impairment based on a new screening instrument to assess communication and language skills at 18 mo of age. METHODS: At 18 mo, 58 children were assessed with a screening instrument for communication and language consisting of a professional assessment and a parents' questionnaire. Students of speech and language pathology, well trained in child language assessment, carried out the professional assessment, which was based on observations of play behaviour, interaction and expressive and receptive language skills. Of the 58 children, 43 attended a follow-up assessment of language skills at 54 mo of age. RESULTS: Nine children were considered to be at risk for language impairment at 18 mo and 10 children were evaluated as being at risk at 54 mo. A significant positive correlation was found between the professional evaluations at 18 mo and the language tests at 54 mo. Verbal comprehension and pretend play correlated significantly with the results on the language tests. CONCLUSION: A professional screening of communication and language at 18 mo of age is worthwhile for predicting problems in language development. The results further show that language comprehension and pretend play rather than expressive skills should be emphasized.

A preliminary version of a computerized naming test for preschool children with language impairment.

The most prevailing hypothesis regarding mechanisms behind specific language impairment today is the hypothesis of general limitations of processing capacity. Such an hypothesis can hardly be tested by available language assessment tools, especially not by instruments in use for clinical assessment of the lexical-semantic domain in children. Reduced naming speed is by some researchers considered as a core deficit in dyslexia and a better predictor of some aspects of reading proficiency than phonological processing. The overall purpose of the present study was therefore to develop a processing dependent tool, that could capture dynamic aspects of naming; response latencies, hesitation phenomena and contextual influence. We also present data from 30 children (4-6 years old) with normal language development. We believe that, with some modifications, the naming test has a potential of becoming a processing dependent measure of naming and a necessary complement to the assessment of vocabulary skills in children with language impairment.

Non-word repetition in children with language impairment--pitfalls and possibilities.

Specific language impairment has, although not without controversy, been considered as a consequence of a phonological memory deficit. Non-word repetition has been proposed as a reliable index of phonological memory and also as predictive of lexical and grammatical development in normally developing and language-impaired children. The main aim was to study the relationship between repetition of words and non-words and expressive language skills (phonology and grammar) in 27 5-year-old children with language impairment. The authors also wanted to explore the influence of lexical stress on repetition skills. The results showed that words were significantly easier to repeat than non-words and that non-word repetition skills were significantly correlated to phonological and grammatical development. The most important predictor of non-word repetition skills was output phonology. The conclusion is that non-word repetition is not a single, reliable index of phonological memory in preschool children with language impairment. Also, the influence of prosodic variables on segmental aspects of speech production should not be overlooked in non-word construction, since it was found that unstressed syllables were omitted six times more often in prestressed than in post-stressed positions of the words and non-words.

The picture superiority effect in a cross-modality recognition task.

Words and pictures were studied and recognition tests given in which each studied object was to be recognized in both word and picture format. The main dependent variable was the latency of the recognition decision. The purpose was to investigate the effects of study modality (word or picture), of congruence between study and test modalities, and of priming resulting from repeated testing. Experiments 1 and 2 used the same basic design, but the latter also varied retention interval. Experiment 3 added a manipulation of instructions to name studied objects, and Experiment 4 deviated from the others by presenting both picture and word referring to the same object together for study. The results showed that congruence between study and test modalities consistently facilitated recognition. Furthermore, items studied as pictures were more rapidly recognized than were items studied as words. With repeated testing, the second instance was affected by its predecessor, but the facilitating effect of picture-to-word priming exceeded that of word-to-picture priming. The finds suggest a two- stage recognition process, in which the first is based on perceptual familiarity and the second uses semantic links for a retrieval search. Common-code theories that grant privileged access to the semantic code for pictures or, alternatively, dual-code theories that assume mnemonic superiority for the image code are supported by the findings. Explanations of the picture superiority effect as resulting from dual encoding of pictures are not supported by the data.