Biomedical subjects

Marja Laasonen

Publications and source records attributed to Marja Laasonen.

5 recordsLinked to original sources

PubMed2005

Perception of matching and conflicting audiovisual speech in dyslexic and fluent readers: an fMRI study at 3 T.

We presented phonetically matching and conflicting audiovisual vowels to 10 dyslexic and 10 fluent-reading young adults during "clustered volume acquisition" functional magnetic resonance imaging (fMRI) at 3 T. We further assessed co-variation between the dyslexic readers' phonological processing abilities, as indexed by neuropsychological test scores, and BOLD signal change within the visual cortex, auditory cortex, and Broca's area. Both dyslexic and fluent readers showed increased activation during observation of phonetically conflicting compared to matching vowels within the classical motor speech regions (Broca's area and the left premotor cortex), this activation difference being more extensive and bilateral in the dyslexic group. The between-group activation difference in conflicting > matching contrast reached significance in the motor speech regions and in the left inferior parietal lobule, with dyslexic readers exhibiting stronger activation than fluent readers. The dyslexic readers' BOLD signal change co-varied with their phonological processing abilities within the visual cortex and Broca's area, and to a lesser extent within the auditory cortex. We suggest these findings as reflecting dyslexic readers' greater use of motor-articulatory and visual strategies during phonetic processing of audiovisual speech, possibly to compensate for their difficulties in auditory speech perception.

Acoustic Stimulation↗

PubMed2004

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.

Analysis of Variance↗

PubMed2003

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.

Acoustic Stimulation↗

PubMed2002

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.

Acoustic Stimulation↗

PubMed2002

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.

Adult↗