Children's history of speech-language difficulties: genetic influences and associations with reading-related measures

PURPOSE

This study examined (a) the extent of genetic and environmental influences on children's articulation and language difficulties and (b) the phenotypic associations between such difficulties and direct assessments of reading-related skills during early school-age years.

METHOD

Behavioral genetic analyses focused on parent-report data regarding the speech-language skills of 248 twin pairs (M = 6.08 years) from the Western Reserve Reading Project. In addition, phenotypic associations between children's speech-language status and direct assessments of early reading-related abilities were examined through hierarchical linear modeling (HLM).

RESULTS

Probandwise concordance rates and intraclass tetrachoric correlations indicated high heritability for children's difficulties in expressive language and articulation, with estimates of .54 and .97 accordingly. HLM results indicated that children with histories of speech-language difficulties scored significantly lower than unaffected children on various measures of early reading-related abilities.

CONCLUSIONS

Results from the parent-report survey provided converging evidence of genetic effects on children's speech and language difficulties and suggest that children with a history of speech-language difficulties are at risk for lower performance on early reading-related measures. The extent of risk differed across measures and appeared greatest for children who demonstrated a history of difficulties across articulation, expressive language, and receptive language. Implications for future genetic research and clinical practice are discussed.

Verbal fluency impairments among middle-aged and older outpatients with schizophrenia are characterized by deficient switching

Patients with schizophrenia demonstrate impaired verbal fluency, but no studies have examined the underlying cognitive mechanisms (e.g., clustering and switching) associated with impaired fluency among middle-aged and older, non-institutionalized patients. Using Troyer et al.'s [Troyer, A.K., Moscovitch, M., Winocur, G., 1997. Clustering and switching as two components of verbal fluency: evidence from younger and older healthy adults. Neuropsychology 11 (1), 138-146] conceptual model, we examined clustering and switching on verbal fluency tasks among 163 middle-aged and older outpatients with schizophrenia and 92 age comparable healthy comparison (HC) participants. The patients produced significantly fewer total words than HC participants on both the letter ("F", "A", "S") and Animal fluency conditions. With regard to clustering, patients were similar to HC participants on both FAS and Animal fluency tasks. However, significantly fewer switches between lexical-semantic categories were observed among patients with schizophrenia on both conditions relative to HC participants. A small, but statistically significant association was found between number of switches on the Animal fluency task and severity of negative symptoms. The absence of a difference in mean cluster size between the patient and HC groups suggests intact lexical-semantic stores among middle-aged and older outpatients with schizophrenia. Differences in switching between patients and HC participants may be driven by several cognitive impairments associated with schizophrenia. Further delineation of the cognitive mechanisms of the observed lexical-semantic switching deficits in schizophrenia should be a focus of future research.

A longitudinal study of quantitative and qualitative features of category verbal fluency in incident Alzheimer's disease subjects: results from the PAQUID study

Category fluency tests were administered at baseline and after 3 and 5 years on two subgroups of subjects from a population-based cohort of elderly subjects: 52 cases of incident possible and probable Alzheimer's disease (AD) and 104 age- and education-matched subjects who remained nondemented. Quantitative and qualitative features of category fluency were assessed to determine how changes occur within 5 years of the diagnosis of AD. Consistent with previous results, we found that the number of words produced on this task was already significantly lower 5 years before the diagnosis in subjects with incident AD as compared with subjects who did not become demented. However, the rate of repetitions only significantly increased in AD subjects at the time of diagnosis, and the rate of intrusions remained low and not significantly different between the two groups. Thus, it is concluded that dysfunction in cognitive processes underlying repetitions and intrusions in verbal fluency tasks, such as inhibitory processes and working memory, may not be the main cause of the very early deficit in verbal fluency occurring in AD.

Psychosocial outcomes at 15 years of children with a preschool history of speech-language impairment

BACKGROUND

Evidence suggests there is a heightened risk of psychiatric disorder in children with speech-language impairments. However, not all forms of language impairment are strongly associated with psychosocial difficulty, and some psychiatric disorders (e.g., attention deficit/hyperactivity disorder (ADHD)) are more prevalent than others in language-impaired populations. The present study assessed the psychosocial adjustment in adolescence of young people with history of speech-language impairment, and investigated specific relationships between language deficits and psychiatric disorders.

METHODS

Seventy-one young people (aged 15-16 years) with a preschool history of speech-language impairment were assessed using a psychiatric interview (K-SADS) supplemented by questionnaires probing social encounters and parental reports of behaviour and attention. Their psycho-social adjustment was compared with that of a cross-sectional control group of age-matched controls.

RESULTS

Overall the rate of psychiatric disorder was low in the clinical sample and children whose language delay had resolved by 5.5 years had a good outcome. For those whose language difficulties persisted through the school years, there was a raised incidence of attention and social difficulties. These difficulties were partially independent and associated with different language profiles. The group with attention problems showed a profile of specific expressive language difficulties; the group with social difficulties had receptive and expressive language difficulties; and the group with both attention and social difficulties was of low IQ with global language difficulties.

CONCLUSIONS

Amongst children with speech-language delays at 5.5 years, those with more severe and persistent language difficulties and low nonverbal IQ are at higher risk of psychiatric morbidity in adolescence.

Teaching Young Nonverbal Children with Autism Useful Speech: A Pilot Study of the Denver Model and PROMPT Interventions

This single subject design study examined two models of intervention: Denver Model (which merges behavioral, developmental, and relationship-oriented intervention), and PROMPT (a neuro-developmental approach for speech production disorders). Ten young, nonverbal children with autism were matched in pairs and randomized to treatment. They received 12 1-h weekly sessions of therapy and daily 1-h home intervention delivered by parents. Fidelity criteria were maintained throughout. Eight of the ten children used five or more novel, functional words spontaneously and spoke multiple times per hour by the conclusion of treatment. There were no differences in acquired language skills by intervention group. Initial characteristics of the best responders were mild to moderate symptoms of autism, better motor imitation skills, and emerging joint attention skills.

Neurocognitive Outcomes in Off-Pump Versus On-Pump Bypass Surgery: A Randomized Controlled Trial

BACKGROUND

Cognitive difficulties have been reported after coronary artery bypass graft surgery using cardiopulmonary bypass. However, the cognitive benefit of off-pump surgery remains unclear.

METHODS

Consecutively listed candidates for elective bypass were randomly assigned to either off-pump or on-pump techniques (n = 107). A battery of 11 standardized neuropsychological tests was administered before surgery, and again at 2 and 6 months after surgery. The two groups were compared using a range of statistical procedures, including growth modeling.

RESULTS

There were no significant differences in cognitive test scores between the off-pump and on-pump groups using t tests at any of the time points. There were no differences between off-pump and on-pump groups in the incidence of cognitive deficits at 2 months or 6 months, with the exception that fewer off-pump patients showed impairment on one test of verbal fluency at 6 months. When the pattern of cognitive change over time between the two groups was compared using sophisticated modeling techniques, the two groups were again comparable, except for results on the test of verbal fluency, in which the off-pump group showed more rapid postsurgical cognitive gains than the on-pump group.

CONCLUSIONS

The off-pump group appears to be generally comparable to the on-pump group in terms of short-term and long-term postsurgical neurocognitive outcomes.

Early speech- and language-impaired children: linguistic, literacy, and social outcomes

The aim of this study was to follow-up prospectively a cohort of preschool children originally recruited from successive referrals to speech and language therapy community clinics and to investigate their linguistic, literacy, and social outcomes at 7 to 10 years of age. Three hundred and fifty children aged 84 to 113 months (mean age 99.9mo [SD 5.4mo]) were singletons from monolingual backgrounds where there was concern about their speech and language development. Children who had severe learning difficulties, autism, oromotor deficits, dysfluency, or dysphonia were excluded. Altogether 196 (56%), 134 males and 62 females, were seen at follow-up. A control group of children who had never been referred for speech and language therapy, 57% of whom were males, was also recruited (n=94; mean age 104.4mo [SD 6.8mo]). All children were assessed on standardized measures of speech, language, and literacy. Teachers and parents completed questionnaires on educational and social outcomes. In total, 139 children in the cohort were within the normal range on standardized language assessments. About 30% of the original cohort of children continue to struggle with language, literacy, and social difficulties. The study demonstrates the long-term nature of language impairment and reinforces the need for awareness among professionals in child development and education of the ongoing needs of this population of children.

Standardised speech-language tests and students with intellectual disability: a review of normative data

BACKGROUND

Before a school speech-language pathologist (SLP) utilises a standardised speech-language test with a student with intellectual disability (ID), the clinician should carefully consider the purpose of the test and whether the test includes students with ID in the normative group.

METHOD

This project reviewed 49 tests published between 1994 and 2004 and their applicability to students with ID.

RESULTS

Students with mild ID were included in the norm group for 23 of the tests, but no tests included students with more significant ID. Separate norms for students with mild ID were included in 15 tests, but none met Salvia & Ysseldyke's (1995) suggested requirement that at least 100 students be included to represent a specific subgroup. A majority of the tests assessed receptive and expressive vocabulary, syntax, and grammar but no recent test measured a student's pragmatic communication.

CONCLUSIONS

Clinicians are encouraged to supplement standardised tests with non-standardised procedures to document students' pragmatic, social, and functional communication abilities.

Limitations in verbal fluency following heavy burdens of early childhood diarrhea in Brazilian shantytown children

The effects of heavy burdens of diarrhea in the first 2 years of life on specific executive control function like verbal fluency are not well understood. In previous studies, we have shown associations of early childhood diarrhea (ECD) with nonverbal intelligence and school functioning. Therefore, we postulated that ECD might affect early neuropsychological development leading to long-term deficits in normal cognitive development. Based on our extensive 14-year prospective cohort studies of early childhood diarrheal illnesses in a Brazilian shantytown community, we examined ECD correlations between specific impairments of higher mental function and executive skills in shantytown children 5-10 years later (now at 6-12) years of age. Specifically we examined whether heavy diarrheal illnesses correlate with reduced performance on selected tests of executive function. Our study, for the first time, suggests a disproportional impairment in semantic but not phonetic fluency in a subset of children with heavy burdens of diarrhea in their first 2 years of life even when controlling for maternal education, breastfeeding, and child schooling. Similar semantic decrements have been associated with impaired recovery from brain injury. These exploratory studies suggest the importance of verbal fluency tests to assess executive functioning in children challenged by poor nutrition and diarrhea in early life. In addition, our unique findings show the potential influences of early childhood diarrhea on language development that is so critical to productive adulthood and potentially set a foundation for new neuropsychological approaches, which assess early burdens of enteric illnesses on childhood development.

[Neuropsychology of mildly disabled patients with relapsing-remitting multiple sclerosis]

Previous papers have mainly demonstrated the presence of cognitive impairment in patients with multiple sclerosis (MS), these changes have been traditionally associated with the later stages of the disease. In the current study, a comprehensive neuropsychological battery was administered to 216 relapsing-remitting MS patients with mild clinical disability (EDSS<or=3.5) and to 35 healty controls. The results show the presence of significant memory impairment: learning rate of list of words; reproduction visual memory; and long term verbal memory of texts, and information processing speed. We also observed greeter incidence of depressive symptoms in patients. And a little relation of the cognitive deficits with the clinical variables in these phase of the disease.

Deep brain stimulation: Postoperative issues

Numerous factors need to be taken into account when managing a patient with Parkinson's disease (PD) after deep brain stimulation (DBS). Questions such as when to begin programming, how to conduct a programming screen, how to assess the effects of programming, and how to titrate stimulation and medication for each of the targeted sites need to be addressed. Follow-up care should be determined, including patient adjustments of stimulation, timing of follow-up visits and telephone contact with the patient, and stimulation and medication conditions during the follow-up assessments. A management plan for problems that can arise after DBS such as weight gain, dyskinesia, axial symptoms, speech dysfunction, muscle contractions, paresthesia, eyelid, ocular and visual disturbances, and behavioral and cognitive problems should be developed. Long-term complications such as infection or erosion, loss of effect, intermittent stimulation, tolerance, and pain or discomfort can develop and need to be managed. Other factors that need consideration are social and job-related factors, development of dementia, general medical issues, and lifestyle changes. This report from the Consensus on Deep Brain Stimulation for Parkinson's Disease, a project commissioned by the Congress of Neurological Surgeons and the Movement Disorder Society, outlines answers to a series of questions developed to address all aspects of DBS postoperative management and decision-making with a systematic overview of the literature (until mid-2004) and by the expert opinion of the authors. The report has been endorsed by the Scientific Issues Committee of the Movement Disorder Society and the American Society of Stereotactic and Functional Neurosurgery.

Language learning in Down syndrome: The speech and language profile compared to adolescents with cognitive impairment of unknown origin

Children and adolescents with Down syndrome show an emerging profile of speech and language characteristics that is typical of the syndrome (Chapman & Hesketh, 2000; Chapman, 2003; Abbeduto & Chapman, 2005) and different from typically developing children matched for nonverbal mental age, including expressive language deficits relative to comprehension that are most severe for syntax, and, in adolescence, strengths in comprehension vocabulary, improvements in expressive syntax, but losses in comprehension of syntax (Chapman, Hesketh & Kistler, 2002). Here we compare 20 adolescents with Down syndrome to 16 individuals with cognitive impairment of unknown origin, statistically matched for age and nonverbal mental age, to show that the age-related strengths in vocabulary comprehension are not limited to the Down syndrome phenotype, but are limited to a certain type of vocabulary test: for both groups, performance on the Peabody Picture Vocabulary Test-3 is significantly greater than performance on the vocabulary subtest of the Test of Auditory Comprehension of Language-3, which does not differ from the syntax comprehension subtests. Vocabulary size, but not conceptual level, is a strength for adolescents with cognitive impairment. In contrast, deficits in auditory-verbal working memory, syntax and vocabulary comprehension, and narration of picture-books without an opportunity to preview them are all specific to the adolescent group with Down syndrome. The expressive language deficit disappears when a preview opportunity and picture support is given.

[Hearing function in children with speech retardation]

Hearing function was studied in 140 children aged between 2 and 5 years with speech retardation and perinatal pathology for formulation of further treatment policy and rehabilitation. Impedance audiometry, SEAAE, game audiometry identified hearing loss of the first, second, third, forth degree in 6 (4%), 10 (7%), 24 (17%), 31 (21%) children respectively. Deafness was registered in 17 (12%) children, 52 (37%) examinees were audiologically normal.

International adoption: a health and developmental prospective

Adoptions from international countries have become an option for many US families, with over 150,000 children adopted in the past 14 years. Typically, internationally adopted children present with a host of medical and developmental concerns. Issues such as growth stunting, abnormal behaviors, and significant delays in motor, speech, and language development are likely directly related to the prenatal and early postnatal environment experienced prior to adoption. The new family and its health-care team must quickly work to identify and address these issues to aid the child's integration into his or her new family. This article will examine potential issues seen in children who are being adopted, including the impact of early environment on subsequent development. We will summarize early and long-term medical issues and review the extent of developmental delays seen in children adopted internationally. Finally, we will discuss possible mechanisms leading to the observed delays, including the impact of stress on subsequent development. By understanding the extent of expected delays and the mechanisms likely causing the issues, the health-care team will be in a good position to quickly identify and develop intervention protocols that will foster the child's assimilation into his or her new family.

The impact of developmental speech and language impairments on the acquisition of literacy skills

Children with developmental speech/language impairments are at higher risk for reading disability than typical peers with no history of speech/language impairment. This article reviews the literacy outcomes of children with speech/language impairments, clarifying the differential risk for three groups of children: speech production impairments alone, oral language impairments alone, and speech production and oral language impairments. Children at greatest risk for reading and writing disabilities are children with language impairments alone and children with comorbid speech impairments and language impairments. For children with speech impairments alone, there is limited risk for literacy difficulties. However, even when reading skills are within the average range, children with speech impairments may have difficulties in spelling. Children with language impairments are likely to display reading deficits in word decoding and reading comprehension. It is not clear what role early literacy interventions play in the amelioration of reading difficulties in these populations.

[Subjective aspects in mothers of speech impaired children]

OBJECTIVE

The purpose of this study was to evaluate the subjective burden in mothers of speech impaired children against the presence or absence of emotional disorders such as anxiety and depression.

METHODS

A total of 89 mothers (age 33.3+/-5.5 years, range: 19.6-43.8 years) of 89 speech impaired preschool children (23 girls, 66 boys, age: 3.9+/-1.5 years, range: 1.6-7.1 years) were examined. Screening for a depressive or anxiety disorder was performed using the German version of the Hospital Anxiety and Depression Scale HADS-D. The "Short Questionnaire on Current Burden" (Kurzfragebogen zur Aktuellen Belastung, KAB) was used to measure the level of perceived subjective burden at the time of the investigation.

RESULTS

A higher score in the KAB test occurred significantly more often in mothers with a positive HADS depression/anxiety subscale result than in those with a negative one.

CONCLUSIONS

There is a need for specific assessment of wellbeing in mothers of speech impaired children. In clinical practice, one may restrict oneself to the use of a screening test for anxiety and depression.

Speech and Language Development in Cognitively Delayed Children With Cochlear Implants

OBJECTIVE

The primary goals of this investigation were to examine the speech and language development of deaf children with cochlear implants and mild cognitive delay and to compare their gains with those of children with cochlear implants who do not have this additional impairment.

DESIGN

We retrospectively examined the speech and language development of 69 children with pre-lingual deafness. The experimental group consisted of 19 children with cognitive delays and no other disabilities (mean age at implantation = 38 months). The control group consisted of 50 children who did not have cognitive delays or any other identified disability. The control group was stratified by primary communication mode: half used total communication (mean age at implantation = 32 months) and the other half used oral communication (mean age at implantation = 26 months). Children were tested on a variety of standard speech and language measures and one test of auditory skill development at 6-month intervals.

RESULTS

The results from each test were collapsed from blocks of two consecutive 6-month intervals to calculate group mean scores before implantation and at 1-year intervals after implantation. The children with cognitive delays and those without such delays demonstrated significant improvement in their speech and language skills over time on every test administered. Children with cognitive delays had significantly lower scores than typically developing children on two of the three measures of receptive and expressive language and had significantly slower rates of auditory-only sentence recognition development. Finally, there were no significant group differences in auditory skill development based on parental reports or in auditory-only or multimodal word recognition.

CONCLUSIONS

The results suggest that deaf children with mild cognitive impairments benefit from cochlear implantation. Specifically, improvements are evident in their ability to perceive speech and in their reception and use of language. However, it may be reduced relative to their typically developing peers with cochlear implants, particularly in domains that require higher level skills, such as sentence recognition and receptive and expressive language. These findings suggest that children with mild cognitive deficits be considered for cochlear implantation with less trepidation than has been the case in the past. Although their speech and language gains may be tempered by their cognitive abilities, these limitations do not appear to preclude benefit from cochlear implant stimulation, as assessed by traditional measures of speech and language development.

Three Diagnostic Approaches to Asperger Syndrome: Implications for Research

OBJECTIVE

To examine the implications for research of the use of three alternative definitions for Asperger syndrome (AS). Differences across the three nosologic systems were examined in terms of diagnostic assignment, IQ profiles, comorbid symptoms, and familial aggregation of social and other psychiatric symptoms.

METHOD

Standard data on diagnosis, intellectual functioning, comorbidity patterns, and family history were obtained on 65 individuals screened for a very high probability of having autism without mental retardation (or higher functioning autism, HFA) or AS. Diagnoses of AS were established based on three different approaches: DSM-IV, presence/absence of communicative phrase speech by 3 years, and a system designed to highlight prototypical features of AS.

RESULTS

Agreement between the three diagnostic systems was poor. AS could be differentiated from HFA (but not from PDD-NOS) on the basis of IQ profiles in two of the three systems. Differences in patterns of comorbid symptomatology were obtained in two of the three systems, although differences were primarily driven by the PDD-NOS category. Only one of the approaches yielded differences relative to aggregation of the "broader phenotype" in family members.

CONCLUSIONS

Diagnostic assignments of AS based on three commonly used approaches have low agreement and lead to different results in comparisons of IQ profiles, patterns of comorbidity, and familial aggregation of psychiatric symptoms across the approach-specific resultant groups of HFA, AS, and PDD-NOS.

Developmental impairments following severe falciparum malaria in children

OBJECTIVE

Neurological deficits are reported in children after cerebral malaria (CM) but little is known about the prevalence and characteristics of persisting neurocognitive consequences. The prevalence of developmental impairments following other complications of falciparum malaria, such as multiple, prolonged or focal seizures, is not known. Thus, our objective was to investigate the long-term developmental outcome of CM and malaria with complicated seizures (M/S).

METHODS

We followed up a cohort of children previously exposed to CM or M/S and children unexposed to either condition. All children between 6 and 9 years of age, exposed to CM, and an equal number of children exposed to M/S were identified from databases of hospital admissions from 1991 to 1998. The unexposed group was randomly selected from a census database. The children's performance was measured using assessments of cognition, motor, speech and language, hearing and vision. A parental questionnaire was used to identify children with epilepsy.

RESULTS

CM group scores were significantly lower than unexposed group scores on the assessments of higher level language (adjusted mean difference -1.63, 95% CI: -2.99 to -0.27), vocabulary (-0.02, 95% CI: -0.04 to -0.01), pragmatics (OR 2.81, 95% CI: 1.04-7.6) and non-verbal functioning (-0.33, 95% CI: -0.61 to -0.06). The areas of significantly reduced functioning for the M/S group were concentrated on phonology (OR 2.74, 95% CI: 1.26-5.95), pragmatics (OR 3.23, 95% CI: 1.2-8.71) and behaviour (OR 1.8, 95% CI: 1.0-3.23). The performance of the active epilepsy group was significantly poorer than that of the group without epilepsy on the tests of comprehension, syntax, pragmatics, word finding, memory, attention, behaviour and motor skills.

CONCLUSIONS

CM and M/S are associated with developmental impairments. If these impairments persist, this may have implications for least 250,000 children in Sub-Saharan Africa each year. Active epilepsy significantly increases the risk of cognitive and behavioural problems in children with a history of severe malaria.

[Communication and speech disorders and their relationship with psychic development and mental disorders in 8 year old children from the Lódź area]

AIM

The aim of the study was to analyze the occurrence of communication and speech disorders among 8-year-old children in Lódź. The comorbidity of these disorders with mental and somatic disorders was also analysed. We have also studied the correlation between the level of language development and the level of psychic development, and the existence and character of mental disorders.

METHOD

The study comprised 7881 children from Lódź, born in 1991. The design of the study was two-stage. Stage I consisted of a screening test, using the Questionnaire of Child-Environment Communication Development, which was sent to the parents of all children. On this basis a group of 58 children with communication disorders was identified, which were further evaluated in the stage II of the study. Stage II consisted of a psychiatric examination, Screening Logopedic Test acc.to Tarkowski, Child Developmental Questionnaire acc. to Rabe-Jabłońska and Gmitrowicz, somatic state evaluation and analysis of the available documentation.

RESULTS

In 0.81% of the children communication disorders were found. Speech disorders were present in all cases: in 2/3rds expressive language disorders or mixed receptive-expressive language disorders, in the remaining cases phonological disorders. Estimated frequency of occurrence of specific disorders in the studied population was as follows: specific developmental language disorders 2.9/1000, acquired aphasia with epilepsy 4/10000, autistic disorder 6.4/10000. Over one third of children with a verbal communication disorder suffered also from various neurological and developmental disorders; most of the children showed abnormal mental development (f = 0.86) and mental disorders (f = 0.66).

CONCLUSIONS

Poor language development correlated statistically significantly with mental retardation, pervasive developmental disorder and behaviour disorders, caused by brain damage or brain dysfunction. Children with a communication disorder who demonstrated normal language development suffered from social maladaptation or ADHD statistically significantly more frequently.

National autism prevalence trends from United States special education data

OBJECTIVE

Reports of large increases in autism prevalence have been a matter of great concern to clinicians, educators, and parents. This analysis uses a national data source to compare the prevalence of autism with that of other disabilities among successive birth cohorts of US school-aged children.

DESIGN

Comparison of birth cohort curves constructed from administrative data.

SETTING AND POPULATION

US children 6 to 17 years of age between 1992 and 2001.

MAIN OUTCOME MEASURES

A disability category classification of autism, mental retardation, speech and language impairment, traumatic brain injury, or other health impairment, as documented by state departments of education and reported to the Office of Special Education Programs, US Department of Education.

RESULTS

Prevalences of disability category classifications for annual birth cohorts from 1975 to 1995 were calculated by using denominators from US Census Bureau estimates. For the autism classification, there were birth cohort differences, with prevalences increasing among successive (younger) cohorts. The increases were greatest for annual cohorts born from 1987 to 1992. For cohorts born after 1992, the prevalence increased with each successive year but the increases did not appear to be as great, although there were fewer data points available within cohorts. No concomitant decreases in categories of mental retardation or speech/language impairment were seen. Curves for other health impairments, the category including children with attention-deficit/hyperactivity disorder, also showed strong cohort differences.

CONCLUSIONS

Cohort curves suggest that autism prevalence has been increasing with time, as evidenced by higher prevalences among younger birth cohorts. The narrowing in vertical separation of the cohort curves in recent years may mark a slowing in the autism prevalence increase.

Disorders of speech development: diagnostic and treatment aspects

Language acquisition is a complex process relying on the well-tuned interaction of a variety of factors. Its genetic base is still little explored, but perhaps plays the most important role during the early periods of this process. In addition, neurological, cognitive and emotional abilities of the child as well as verbal stimulation from the environment are crucial. Language development disorders manifest themselves as late onset, slow progression or as erroneous course of the language development. Because of the multitude of factors involved, their aetiology is frequently difficult to determine. Diagnosis of such disorders commonly requires the cooperation of several professionals, like paediatricians, otolaryngologists, psychologists, and speech pathologists. The "late bloomer" hypothesis suggests, that up to 50% of children presenting with language problems in early years, make up for them without intervention up to age four years. Nevertheless, treatment for a language problem, as soon as it appears, is generally recommended in order to minimize adverse effects on succeeding developmental steps.

Childhood stuttering and dissociations across linguistic domains

The purpose of this investigation was to evaluate the possible presence of dissociations in the speech and language skills of young children who do (CWS) and do not stutter (CWNS) using a correlation-based statistical procedure [Bates, E., Appelbaum, M., Salcedo, J., Saygin, A. P., & Pizzamiglio, L. (2003). Quantifying dissociations in neuropsychological research. Journal of Clinical and Experimental Neuropsychology, 25, 1128-1153]. Participants were 45 preschool CWS and 45 CWNS between the ages of 3;0 and 5;11 (years;months), with the two groups matched by age, gender, race, and parental socioeconomic status. Children participated in a parent-child interaction for the purpose of disfluency analysis and responded to four standardized speech-language tests for subsequent analyses as main dependent variables. Findings indicated that CWS were over three times more likely than CWNS to exhibit dissociations across speech-language domains, with 44 cases of dissociation for CWS and 14 for CWNS across 10 possible comparisons. Results suggest that there may be a subgroup of CWS who exhibit dissociations across speech-language domains, which may result in a greater susceptibility to breakdowns in speech fluency.

EDUCATIONAL OBJECTIVES

The reader will be able to: (1) summarize findings from previous studies examining differences in speech and language performance between children who do and do not stutter; (2) describe what is meant by "dissociations" in the speech and language skills of young children who do and do not stutter; and (3) discuss three hypotheses that could account for the present findings that suggest CWS, more often than CWNS, exhibit dissociations in their speech-language system.

Neurocognitive profiles in Salla disease

Salla disease, a free sialic acid storage disorder, is one of the 36 currently known disorders in Finland that form the Finnish disease heritage. Salla disease leads to learning disability* with a wide clinical variation. Two main categories of the disease have been classified: a conventional subtype and a severe subtype with more severe defects. We present detailed neurocognitive profiles of 41 Finnish patients with Salla disease (19 females, 22 males; age range 11mo to 63y, median 19y). The neurocognitive development of patients with Salla disease was assessed by psychological and neuropsychological testing. All patients were also examined by a paediatric neurologist and a speech therapist. The characteristic cognitive profile consisted of a lower non-verbal performance (mean developmental age 13mo) compared with linguistic skills (mean developmental age 17mo). In particular, spatial and visual-constructive impairments were typical of these patients. Tactile and visual discrimination of forms was poor. Tasks demanding hand-eye coordination, maintenance of visual attention, and those requiring short-term visual memory and executive skills were performed better. Receptive language skills were notably better compared with expressive speech. The patients' interactive and non-verbal communication skills were quite strong. Another typical pattern with Salla disease was severe motor disability. After the second decade of life, the decline in these skills was more pronounced than patients' cognitive deterioration. Our results indicate that even though there is a considerable variation in the clinical findings of patients with Salla disease, the characteristic neurocognitive profile of the disease can be outlined.