Serum lipid fatty acids, phonological processing, and reading in children with oral clefts

Reading skill is suggested to be related to phonological processing ability and polyunsaturated fatty acids (PUFAs). Here we investigated whether fatty acids (FAs) are related to phonological processing, whether the relations between PUFAs and reading generalize to other FAs, whether these relations are mediated by phonological processing, and whether relations of FAs are specific for language-related functions. Blood samples of 49 ten-year-old children with oral clefts were collected for FA proportion analysis in serum cholesteryl esters and phospholipids. On the same day, they performed tasks of phonological processing, reading, and both verbal and nonverbal intelligence. Sequential regression analyses (adjusted for age, gender, and cleft type) showed that phonological processing was inversely related to myristic acid in phospholipids and positively related to eicosapentaenoic acid in cholesteryl esters. Reading was inversely related to palmitoleic and gammalinolenic acids in phospholipids. The relations between FAs and reading were not mediated by phonological processing and FAs related only to language-related functions.

Visual, Auditory, and Tactile Temporal Processing in Children With Oral Clefts

Neurocognitive disorders may compromise the outcome of surgical cleft lip palate repair and thus need to be identified. Processing of rapidly changing sequential information (temporal processing) is a fundamental neurocognitive capacity that may contribute to various communication functions and has been found impaired in several developmental disorders. The occurrence of temporal processing difficulties in the cleft population is not known, however. We investigated the relation between oral clefting and temporal estimations of simultaneity/nonsimultaneity in visual, auditory, and tactile modalities. Subjects were 10-year-old controls and children with oral clefts of various types [i.e., cleft lip (alveolar), cleft lip and palate, cleft palate, and cleft palate submucous]. The visual and tactile tasks but not so clearly the auditory task differentiated the groups. Further, paralleling previous findings, the patients with cleft lip and palate outperformed the others, whereas the cognitive temporal processing acuity of the cleft palate and cleft palate submucous children was worse.

Crossmodal temporal processing acuity impairment aggravates with age in developmental dyslexia

Temporal processing has been found to be impaired in developmental dyslexia. We investigated how aging affects crossmodal temporal processing impairment with 39 dyslexic and 40 fluent 20-59-year-old readers. Cognitive temporal acuity was measured at millisecond levels in six tasks. They consisted of order judgments of two brief non-speech stimulus pulses, the stimuli being audiotactile, visuotactile and audiovisual, and of simultaneity/nonsimultaneity detection of the pulses in two parallel three-pulse trains. Temporal acuity declined with age in both reading groups and its impairment was observed in developmental dyslexia. A new finding was that the crossmodal temporal impairment, directly relevant to reading, increased with age. The age-related exacerbation suggests a developmental neuronal deficit, possibly related to magnocells, which exists before dyslexia and is its ontogenetic cause.

Developmentally impaired processing speed decreases more than normally with age

Several studies show that although function may recover after brain damage the insult can nevertheless cause accelerated deterioration in old age. This has been interpreted as indicating reduced neuronal capacity to counteract age-related decline with plastic changes. Psychosocial and compensatory factors obscure the neuronal explanation. Since the speed of processing sequential temporal information is impaired in developmental dyslexia, we investigated its dependence on age (20-59 years) in psychosocially comparable groups of dyslexic and fluent readers using six tasks. Processing speed was impaired in dyslexia and decreased with age. The decrement was faster in dyslexic than normal readers in processing periodic stimuli. No exacerbation occurred in reading and other experiential factors. Our results, therefore, support the neuronal explanation.

Crossmodal temporal order and processing acuity in developmentally dyslexic young adults

We investigated crossmodal temporal performance in processing rapid sequential nonlinguistic events in developmentally dyslexic young adults (ages 20-36 years) and an age- and IQ-matched control group in audiotactile, visuotactile, and audiovisual combinations. Two methods were used for estimating 84% correct temporal acuity thresholds: temporal order judgment (TOJ) and temporal processing acuity (TPA). TPA requires phase difference detection: the judgment of simultaneity/nonsimultaneity of brief stimuli in two parallel, spatially separate triplets. The dyslexic readers' average temporal performance was somewhat poorer in all six comparisons; in audiovisual comparisons the group differences were not statistically significant, however. A principal component analysis indicated that temporal acuity and phonological awareness are related in dyslexic readers. The impairment of temporal input processing seems to be a general correlative feature of dyslexia in children and adults, but the overlap in performance between dyslexic and normal readers suggests that it is not a sufficient reason for developmental reading difficulties.

Temporal order and processing acuity of visual, auditory, and tactile perception in developmentally dyslexic young adults

We studied the temporal acuity of 16 developmentally dyslexic young adults in three perceptual modalities. The control group consisted of 16 age- and IQ-matched normal readers. Two methods were used. In the temporal order judgment (TOJ) method, the stimuli were spatially separate fingertip indentations in the tactile system, tone bursts of different pitches in audition, and light flashes in vision. Participants indicated which one of two stimuli appeared first. To test temporal processing acuity (TPA), the same 8-msec nonspeech stimuli were presented as two parallel sequences of three stimulus pulses. Participants indicated, without order judgments, whether the pulses of the two sequences were simultaneous or nonsimultaneous. The dyslexic readers were somewhat inferior to the normal readers in all six temporal acuity tasks on average. Thus, our results agreed with the existence of a pansensory temporal processing deficit associated with dyslexia in a language with shallow orthography (Finnish) and in well-educated adults. The dyslexic and normal readers' temporal acuities overlapped so much, however, that acuity deficits alone would not allow dyslexia diagnoses. It was irrelevant whether or not the acuity task required order judgments. The groups did not differ in the nontemporal aspects of our experiments. Correlations between temporal acuity and reading-related tasks suggested that temporal acuity is associated with phonological awareness.

Near infrared reflectance spectroscopy for the fast identification of PVC-based films

Near infrared (NIR) reflectance spectroscopy was used to develop a non-destructive and rapid qualitative method for the analysis of plastic films used by the pharmaceutical industry for blistering. Three types of films were investigated: 250 microm PVC [poly(vinyl chloride)] films, 250 microm PVC films coated with 40 g m(-2) of PVDC [poly(vinylidene dichloride)] and 250 microm PVC films coated with 5 g m(-2) of TE (Thermoelast) and 90 g m(-2) of PVDC. Three analyses were carried out using different pre-treatment options and a PLS (partial least squares) algorithm. Each analysis was aimed at identifying one type of film and rejecting all types of false sample (different thickness, colour or layer). True and false samples from four plastics manufacturers were included in the calibration sets in order to obtain robust methods that were suitable regardless of the supplier. Specificity was demonstrated by testing validation sets against the methods. The tests showed 0% of type I (false negative identification) and 1% of type II errors (false positive identification) for the PVC method, 13 and 3%, respectively, for the PVC-PVDC method and no error for the PVC-TE-PVDC method. Type II errors, mostly due to the slight sensitivity of the methods to film thickness, are easily corrected by simple thickness measurements. This study demonstrates that NIR spectroscopy is an excellent tool for the identification of PVC-based films. The three methods can be used by the pharmaceutical industry or plastics manufacturers for the quality control of films used in blister packaging.

Rate of information segregation in developmentally dyslexic children

Slowed processing of sequential perceptual information is related to developmental dyslexia. We investigated this unimodally and crossmodally in developmentally dyslexic children and controls ages 8-12 years. The participants judged whether two spatially separate trains of brief stimuli, presented at various stimulus onset asynchronies (SOA) in one or two senses, were synchronous or not. The stimulus trains consisted of light flashes in vision, clicks in audition, and indentations of the skin in the tactile sense. The dyslexic readers required longer SOAs than controls for successful performance in all six comparisons. The crossmodal spatiotemporal resolution of the groups differed more than unimodal performance. The dyslexic readers' segregation performance was also less differentiated than that of the controls. Our results show that not only sensory but also polysensory nonverbal information processing is temporally impaired in dyslexic children.