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H Lyytinen

Publications and source records attributed to H Lyytinen.

At least 19 recordsLinked to original sources
PubMed2006

Speech- and sound-segmentation in dyslexia: evidence for a multiple-level cortical impairment.

Developmental dyslexia involves deficits in the visual and auditory domains, but is primarily characterized by an inability to translate the written linguistic code to the sound structure. Recent research has shown that auditory dysfunctions in dyslexia might originate from impairments in early pre-attentive processes, which affect behavioral discrimination. Previous studies have shown that whereas dyslexic individuals are deficient in discriminating sound distinctions involving consonants or simple pitch changes, discrimination of other sound aspects, such as tone duration, is intact. We hypothesized that such contrasts that can be discriminated by dyslexic individuals when heard in isolation are difficult to identify when occurring within words or structurally similar complex sound patterns. In the current study, we addressed how segments of pseudo-words and their non-speech counterparts are processed in dyslexia. We assessed the detection of long-duration differences in segments of these stimuli and identified the brain processes that could be associated with the behavioral results. Consistent with previous studies, we found no early cortical sound-duration discrimination deficit in dyslexia. However, differences between impaired and non-impaired readers were found in the brain processes associated with sound-change recognition as well as in the behavioral performance. This suggests that even when the early, automatic, sound discrimination processes are intact in dyslexic individuals, deficits in the later, attention-dependent processes may lead to impaired perception of speech and other complex sounds.

Acoustic Stimulation↗
PubMed2005

Detection of sound rise time by adults with dyslexia.

Low sensitivity to amplitude modulated (AM) sounds is reported to be associated with dyslexia. An important aspect of amplitude modulation cycles are the rise and fall times within the sound. In this study, simplified stimuli equivalent to just one cycle were used and sensitivity to varying rise times was explored. Adult participants with dyslexia or compensated dyslexia and a control group performed a detection task with sound pairs of different rise times. Results showed that the participants with dyslexia differed from the control group in rise time detection and a correlation was found between rise time detection and reading and phonological skills. A subgroup of participants with lower sensitivity to rise time detection characterized by low accuracy in syllable-level phonological skills was found within the dyslexic group. Short stimuli containing only one rise time produced associations with phonological skills and reading, even in a language where the perception of rise time contrasts are not crucial for the signaling of phonemic contrast.

Acoustic Stimulation↗
PubMed2004

Early development of children at familial risk for dyslexia--follow-up from birth to school age.

We review the main findings of the Jyväskylä Longitudinal study of Dyslexia (JLD) which follows the development of children at familial risk for dyslexia (N = 107) and their controls (N = 93). We will illustrate the development of these two groups of children at ages from birth to school entry in the skill domains that have been connected to reading and reading disability in the prior literature. At school entry, the highest score on the decoding task among the poorer half (median) of the at risk children--i.e. of those presumably being most likely genetically affected--is 1 SD below the mean of the control group. Thus, the familial risk for dyslexia shows expected consequences. Among the earliest measures in which group differences as well as significant predictive associations with the first steps in reading have emerged, are indices of speech processing in infancy. Likewise, various measures of early language including pronunciation accuracy, phonological, and morphological skills (but not performance IQ) show both group differences and predictive correlations, the majority of which become stronger as the reliability of the measures increases by age. Predictive relationships tend to be strong in general but higher in the at risk group because of its larger variance in both the predictor variables and in the dependent measures, such as early acquisition of reading. The results are thus promising in increasing our understanding needed for early identification and prevention of dyslexia.

Child↗
PubMed2003

Event-related potentials in newborns with and without familial risk for dyslexia: principal component analysis reveals differences between the groups.

Differences revealed by factor scores extracted by principal component analysis (PCA) from event-related potential (ERP) data of newborns with and without familial risk for dyslexia were examined and compared to results obtained by using original averaged ERPs. ERPs to consonant-vowel syllables (synthetic /ba/, /da/, /ga/; and natural /paa/, /taa/, /kaa/) were recorded from 26 at-risk and 23 control 1-7 day-old infants. The stimuli were presented equiprobably and with interstimulus intervals varying at random from 3,910 to 7,285 ms. Statistically significant between-group differences were found to be relatively similar irrespective of the methods of analysis (original ERPs vs. factor scores from PCA). Responses to /ga/ differed from those to /ba/ and /da/ between the groups in the right hemisphere at the latencies of 50-170 ms (Factor 4) and 540-630 ms (Factor 3). The groups differed also in their responses to /da/ in the posterior electrode sites at 740-940 ms (Factor 2). There were no group differences in the natural stimulus set. These results demonstrate that brain activation differences may be implicated in risk for dyslexia immediately after birth. The results also show that the PCA-ANOVA procedure is an effective way of identifying the group-related variance in the ERP-data when the component structure, such as those of infants, is not well-known in advance.

Acoustic Stimulation↗
PubMed2003

A genome scan for developmental dyslexia confirms linkage to chromosome 2p11 and suggests a new locus on 7q32.

Developmental dyslexia is a distinct learning disability with unexpected difficulty in learning to read despite adequate intelligence, education, and environment, and normal senses. The genetic aetiology of dyslexia is heterogeneous and loci on chromosomes 2, 3, 6, 15, and 18 have been repeatedly linked to it. We have conducted a genome scan with 376 markers in 11 families with 38 dyslexic subjects ascertained in Finland. Linkage of dyslexia to the vicinity of DYX3 on 2p was confirmed with a non-parametric linkage (NPL) score of 2.55 and a lod score of 3.01 for a dominant model, and a novel locus on 7q32 close to the SPCH1 locus was suggested with an NPL score of 2.77. The SPCH1 locus has previously been linked with a severe speech and language disorder and autism, and a mutation in exon 14 of the FOXP2 gene on 7q32 has been identified in one large pedigree. Because the language disorder associated with the SPCH1 locus has some overlap with the language deficits observed in dyslexia, we sequenced the coding region of FOXP2 as a candidate gene for our observed linkage in six dyslexic subjects. No mutations were identified. We conclude that DYX3 appears to be important for dyslexia susceptibility in many Finnish families, and a suggested linkage of dyslexia to chromosome 7q32 will need verification in other data sets.

Chromosome Mapping↗
PubMed2001

Language development and symbolic play in children with and without familial risk for dyslexia.

The purposes of this study were to investigate (a) whether children in families with a positive history of dyslexia were more likely to show delays in language development than children without family risk and (b) whether a delayed onset of expressive language (late talking) predicted later language development. We analyzed the language development of 200 children longitudinally at 14, 24, 30, and 42 months and assessed their symbolic play at 14 months. Half of the children (N = 106) were from families with a history of dyslexia (the Dyslexia Risk [DR] group), and other children served as age-matched controls. Parental reports and structured tests were used to assess children's receptive and expressive language and symbolic play. No differences emerged between the two groups in receptive language, symbolic play, or on the Bayley MDI. The groups, however, diverged in expressive language measures. The maximum sentence length at 2 years and object naming and inflectional morphology skills at 3.5 years were higher for the control group than for the DR group. Reynell receptive score at 2.5 years provided the greatest unique contribution to the prediction of the children's receptive and expressive language. Children's risk status did not contribute to receptive language, but provided a significant contribution to their expressive language at 3.5 years, even after the variance associated with parental education and children's previous language skills was controlled. Late talkers in the DR group differed from the other members of the DR group in both receptive and expressive language at 3.5 years, although in the control group children with a late-talking history performed at age-level expectations. The findings suggest that children with a familial risk for dyslexia and with a history of late talking are at higher risk for delays in language acquisition than children without the familial risk for dyslexia.

Dyslexia↗
PubMed2001

Developmental pathways of children with and without familial risk for dyslexia during the first years of life.

Comparisons of the developmental pathways of the first 5 years of life for children with (N = 107) and without (N = 93) familial risk for dyslexia observed in the Jyväskylä Longitudinal study of Dyslexia are reviewed. The earliest differences between groups were found at the ages of a few days and at 6 months in brain event-related potential responses to speech sounds and in head-turn responses (at 6 months), conditioned to reflect categorical perception of speech stimuli. The development of vocalization and motor behavior, based on parental report of the time of reaching significant milestones, or the growth of vocabulary (using the MacArthur Communicative Development Inventories) failed to reveal differences before age 2. Similarly, no group differences were found in cognitive and language development assessed by the Bayley Scales of Infant Development and the Reynell Developmental Language Scales before age 2.5. The earliest language measure that showed lower scores among the at-risk group was maximum sentence length at age 2. Early gross motor development had higher correlation to later language skills among the at-risk group rather than the control children. The most consistent predictor of differential development between groups was the onset of talking. Children who were identified as late talkers at age 2 were still delayed at the age 3.5 in most features of language-related skills-but only if they belonged to the group at familial risk for dyslexia. Several phonological and naming measures known to correlate with reading from preschool age differentiated the groups consistently from age 3.5. Our findings imply that a marked proportion of children at familial risk for dyslexia follow atypical neurodevelopmental paths. The signs listed previously comprise a pool of candidates for early predictors and precursors of dyslexia, which await validation.

Child↗
PubMed2001

Practice effects on visuomotor and problem-solving tests by children.

Practice effects on a visuomotor test (the Developmental Test of Visuo-Motor Integration), a timed visual discrimination test (the Underlining Test), and two problem-solving tests (the Porteus Mazes Test and the Tower of Hanoi Test) were analyzed. Children of two age groups (Ms: 7.7 and 11.6 yr.) were chosen to study the effect of age on practice effects. The tests were repeated nine times with test-retest intervals of 2 mo. The Developmental Test of Visuo-Motor Integration showed no practice effects, while the Porteus Mazes Test, the Underlining Test, and the Tower of Hanoi Test showed significant practice effects. Practice effects were larger for the older age group on all the tests, except the Developmental Test of Visuo-Motor Integration. The Developmental Test of Visuo-Motor Integration and the Underlining Test showed good reliability, but those of the problem-solving tasks were less satisfactory. The stability of all the tests, except the Tower of Hanoi Test, was good.

Child↗
PubMed2000

Auditory cortex evoked magnetic fields and lateralization of speech processing.

Potential use of different auditory evoked brain responses for determining cerebral lateralization of speech function was evaluated. Cortical magnetic fields elicited by plosive syllables or complex non-speech sounds analogous to them were recorded with 122-channel magnetometer. We estimated parameters of magnetic P1, N1 and P2 responses to both stimuli in the two hemispheres and found no hemispheric asymmetry for any of the responses. No correlation between the right-ear advantage, determined with dichotic listening test, and any of asymmetry indexes, calculated for the speech-elicited responses, was observed. These results suggest that P1, N1 and P2 responses to speech signals do not indicate lateralization of speech function in the brain. The results are discussed in relation to previous studies suggesting that the mismatch negativity (MMN) seems to be the only early auditory cortex response sensitive to the lateralization of speech function.

Adolescent↗
PubMed2000

Aiming routines and their electrocortical concomitants among competitive rifle shooters.

The present study focused on an examination of competitive shooters' aiming process during a rifle shooting task. The barrel movements of the rifle, as detected by a laser system during the last 1000-ms time period preceding the triggering, were recorded from six elite and six pre-elite shooters. Electrocortical slow potentials (SPs) from frontal (Fz), centro-lateral (C3, C4), and occipital (Oz) brain areas were recorded to get an additional insight into the underlying covert processing. The results suggested that the elite shooters did not pull the trigger until they reached a sustained rifle position. In the pre-elite shooters the rifle appeared to be in a less stable position, and their strategy was to take advantage of the first appropriate moment of steadiness without a sustained rifle position so they could pull the trigger. The observed pre-trigger readiness potential (RP) shifts at Fz and Oz were more positive among the elite shooters relative to the pre-elite shooters, reflecting their more pronounced covert effort, rather than increasing preparedness for the trigger pull. The present study lends support for the view that a successful aiming strategy is mainly based on sustained rifle balancing. With regards to the brain slow potentials, it can be concluded that the RP shift does not specifically reflect the preparation for the trigger pull.

Action Potentials↗
PubMed2000

Repeated assessment of the Tower of Hanoi test: reliability and age effects.

The purpose of this research was to analyze the effects of repeating an executive function test. Three versions of the Tower of Hanoi (TOH) test were repeated three times each, with test-retest intervals of 2 months. Two groups of children participated in the research (7.7 and 11.6 years, n = 22 and n = 28). Repeating the assessment improved the performance and decreased the total performance time in both of the groups. The older participants improved their performance faster than the younger ones. The reliability of all the scores, besides the error scores, seemed to be satisfactory after the first few assessments. The stability of the scores was maintained through all the assessments. The planning time did not explain the variations of the achieved score. The reasons for the initially low reliabilities are discussed, and modifications for the test administration and scoring are suggested.

Age Factors↗
PubMed2000

Suggestions for revised scoring of the Tower of Hanoi test.

Detailed time and error analyses of the Tower of Hanoi (TOH) test was performed using four repeated assessments of eight children (ages 9-12 years), who had perceptual and problem solving deficits. The time before each move was measured. In addition to the traditionally counted time scores, new, relative time scores were computed in order to separate the planning time from the general reaction speed. New error scores were defined and sum scores of serious errors (perserative moves, illegal moves, and wrong results) and mild errors (self-corrected moves, almost performed moves, and interrupted trials) were computed. The relative planning time correlated positively with the achieved score, and negatively with the serious errors. The serious errors correlated negatively with the achieved score. The relative planning time seems to measure the quality of planning better than does the raw planning time, and it is a recommended score for TOH analysis. The value of new error scores requires additional research.

Cognition↗
PubMed1999

Cortical responses of infants with and without a genetic risk for dyslexia: I. Age effects.

We studied auditory event-related potentials (ERP) in newborns and 6-month-old infants, about half of whom had a familial risk for dyslexia. Syllables varying in vowel duration were presented in an oddball paradigm, in which ERPs to deviating stimuli are assumed to reflect automatic change detection in the brain. The ERPs of newborns had slow positive deflections typical of their age, but significant stimulus and group effects were found only by the age of 6 months. In both groups, the responses to the deviant /ka/ were more positive than those to the standard /kaa/ stimuli, contrary to the findings of adult ERPs to duration changes. The results also suggested differences in brain activation pattern between the groups.

Acoustic Stimulation↗
PubMed1999

Cortical responses of infants with and without a genetic risk for dyslexia: II. Group effects.

Infants born to families with a background of developmental dyslexia have an increased risk of becoming dyslexic. In our previous study no major group or stimulus effects in the event-related potentials (ERPs) of at-risk and control infants were found until the age of 6 months. However, in the current study, when we made the stimulus presentation rate slower, the ERPs to the short deviant /ka/ were different from those to the long standard /kaa/ stimulus already in newborns. In addition, clear group differences in the ERPs were found. The results demonstrate that infants born with a high familial risk for dyslexia process speech/auditory stimulus durations differently from control infants at birth.

Acoustic Stimulation↗
PubMed1998

Preparatory heart rate patterns in competitive rifle shooting.

In this study, we examined the relationship between preparatory heart rate patterns and competitive shooting performance. Cardiac activity was recorded from six elite and six non-elite male rifle shooters during the 6 s before the trigger pull. The assessment of shooting performance was based on three variables: shooting score, rifle stability and electromyographic (EMG) activity in the upper body. Each shooter showed a decrease in the pre-trigger heart rate that did not covary with the shooting scores. The magnitude of this change was greater for the non-elite shooters compared to the elite shooters, suggesting that the heart rate patterns reflected skill-related aspects of preparatory performance. The analyses of rifle-hold performance (rifle stability and EMG) suggested that the observed heart rate changes were associated with a shooter's attempts to achieve a rigid rifle position, but depend on his skill level. Interpretation of preparatory heart rate patterns in competitive rifle shooting should not be based solely on the attentional focusing aspect, but should also take into account the effects of a shooter's psychomotor regulation.

Adult↗
PubMed1998

Rifle-balancing in precision shooting: behavioral aspects and psychophysiological implication.

This study investigated sharpshooters' strategies to control their rifle stability during the aiming period. Six elite and six pre-elite shooters completed a simulated realistic shooting task (laser rifle), and their performance was evaluated from behavioral and psychophysiological perspectives. The analysis of the rifle's barrel movement, indexing the shooter's behavioral performance, supported the view that rifle-balancing is an essential determinant of superior shooting performance. The psychophysiological data, i.e. the brain slow potentials, suggested that the shooters applied different rifle-hold strategies; the elite shooters concentrated primarily on achieving a stable rifle position using psychomotor regulation, whereas the pre-elite shooters were more reliant on the visual-spatial processing. The present study has implications for the understanding of psychological aspects in competitive precision shooting, as well as for the evaluation of the functional significance of the electrocortical slow potentials in shooting-like closed-skill sports.

Action Potentials↗