The septin cytoskeleton regulates natural killer cell lytic granule release

Natural killer (NK) cell–mediated killing involves the membrane fusion of preformed lytic granules. While the roles of actin and microtubules are well accepted during this process, the function of septins, another cytoskeletal component that associates with actin and microtubules, has not been investigated. Here we show that genetic depletion or pharmacologic stabilization of the septin cytoskeleton significantly inhibited NK cell cytotoxicity. Although the stabilization of septin filaments impaired conjugate formation, depletion of septin proteins had no impact on conjugate formation, lytic granule convergence, or MTOC polarization to the cytotoxic synapse (CS). Interestingly, septins copurify and accumulate near the polarized lytic granules at the CS, where they regulate lytic granule release. Mechanistically, we find that septin 7 interacts with the SNARE protein syntaxin 11 and facilitates its interaction with syntaxin binding protein 2 to promote lytic granule fusion. Altogether, our data identify a critical role for septins in regulating the release of lytic granule contents during NK cell–mediated killing.

Erectile Dysfunction and Cardiovascular Risk in Men With Rheumatoid Arthritis: A Population-based Cohort Study

OBJECTIVE

Both erectile dysfunction (ED) and rheumatoid arthritis (RA) are associated with increased cardiovascular (CV) risk. It is unknown if these diagnoses are associated or if their combination confers additional CV risk. We aimed to define the incidence of ED in RA, and to determine if ED correlates with increased CV risk in RA.

METHODS

Medical information concerning RA, ED, and CV diagnoses for men with RA (n = 260) diagnosed in Olmsted County, Minnesota, and age-matched male comparators was extracted from a comprehensive medical record system.

RESULTS

ED incidence was similar between the RA cohort and comparators (HR 0.80, 95% CI 0.55-1.16). In men with RA, ED diagnosis was associated with a trend toward an increase in peripheral arterial disease (HR 2.22, 95% CI 0.98-5.03) and a significantly decreased rate of myocardial infarction (HR 0.26, 95% CI 0.07-0.90), heart failure (HR 0.49, 95% CI 0.25-0.94), and death (HR 0.56; 95% CI 0.36-0.87). In men with RA and ED, phosphodiesterase-5 inhibitor use was associated with a decreased risk of death (HR 0.35, 95% CI 0.16-0.79), with a trending decreased risk of some CV diagnoses.

CONCLUSION

Incidence of ED was not statistically increased in RA. Although patients with both RA and ED had a similar overall CV risk to those with RA alone, men with both RA and ED had decreased risk of heart failure, myocardial infarction, and death, as well as an increased risk of peripheral arterial disease. Further studies are needed to clarify these associations and their implications for pathogenesis and therapeutics.

Erectile Dysfunction in Men With Psoriatic Arthritis: A Population-based Cohort Study

OBJECTIVE

To define the incidence of erectile dysfunction (ED) in a population-based cohort of men with psoriatic arthritis (PsA).

METHODS

Data pertaining to demographics, ED, and potential confounding diagnosis were extracted from a comprehensive medical record system for a population-based cohort of men with PsA and an age-matched male comparator cohort. Cumulative incidence of ED adjusted for competing risk of death was compared between the 2 cohorts.

RESULTS

There were 128 age-matched pairs of men with PsA and without PsA in the described cohorts. At baseline, there was a 7% prevalence of ED in men with PsA prior to diagnosis compared to a 3% prevalence of ED in the comparator cohort (P = 0.16). After PsA diagnosis/index date, diagnosis with PsA was associated with an increased risk of ED (age-adjusted HR 1.45, 95% CI 0.79-2.68), but this association did not reach statistical significance. This was based on 24 cases of ED in the men with PsA and 18 cases within the comparator cohort. No confounding factors or ED treatment strategies differed significantly between men with PsA and ED and comparators with ED.

CONCLUSION

Men with PsA may have an increased risk of ED, which was detected but likely underpowered in this study. Whether this difference is secondary to higher prevalence of traditional risk factors of ED in men with PsA compared to the general population will require further study.

Developmental brain abnormalities and acute encephalopathy in a patient with myopathy with extrapyramidal signs secondary to pathogenic variants in MICU1

Mitochondria play a variety of roles in the cell, far beyond their widely recognized role in ATP generation. One such role is the regulation and sequestration of calcium, which is done with the help of the mitochondrial calcium uniporter (MCU) and its regulators, MICU1 and MICU2. Genetic variations in MICU1 and MICU2 have been reported to cause myopathy, developmental disability and neurological symptoms typical of mitochondrial disorders. The symptoms of MICU1/2 deficiency have generally been attributed to calcium regulation in the metabolic and biochemical roles of mitochondria. Here, we report a female child with heterozygous MICU1 variants and multiple congenital brain malformations on MRI. Specifically, she shows anterior perisylvian polymicrogyria, dysmorphic basal ganglia, and cerebellar dysplasia in addition to white matter abnormalities. These novel findings suggest that MICU1 is necessary for proper neurodevelopment through a variety of potential mechanisms, including calcium-mediated regulation of the neuronal cytoskeleton, Miro1-MCU complex-mediated mitochondrial movement, or enhancing ATP production. This case provides new insight into the molecular pathogenesis of MCU dysfunction and may represent a novel diagnostic feature of calcium-based mitochondrial disease.

Affinity threshold conversion: the progressive differentiation checkpoint at which the TCRα/CD3δ signaling axis controls thymic positive selection

Upon positive selection of conventional αβ T cells, CD4+ CD8+ double-positive (DP) cells transition to single-positive (SP) and reduce their responsiveness to weak peptide/MHC ligands (affinity threshold conversion, ATC). We report that ATC actually begins prior to the completion of positive selection in the DP stage, and this checkpoint is where the TCRα/CD3δ signaling axis controls positive selection. We dissected ATC in the OT1 TCR transgenic system in conjunction with several different genes whose null mutations block thymic development at DP stage: β2m, CD3δ, and/or TCRα-Connecting Peptide Motif (αCPM). In the absence of MHC class I (β2m0), CD3δ or αCPM mutants were blocked at pre-selection DP stage and displayed immature, high-sensitivity to weak TCR ligands. In contrast, when MHC class I was present (β2m+), CD3δ or αCPM mutants were blocked at DP stage but underwent partial ATC; they began positive selection but did not complete it. Upon exogenous TCR engagement of partial-ATC thymocytes, the proximal signaling protein interaction network showed overall weakened activity, notably decreasing SOS1 participation linked to the downstream Ras/Raf/ERK selection pathway. Provision of high affinity peptide/MHC in FTOC rescued completion of positive selection for partial-ATC mutant thymocytes. Finally, comparing nontransgenic, polyclonal B6 vs. CD3δ0 DP thymocytes, although most cells showed equal maturation state, a subset of cells in B6 progressed in maturation relative to CD3δ0. We propose the existence of an intermediate checkpoint inside DP stage, in which ATC already begins to reduce responsiveness to selection ligands, yet further TCR signaling is required to complete positive selection.

The early proximal αβ TCR signalosome specifies thymic selection outcome through a quantitative protein interaction network

During αβ T cell development, T cell antigen receptor (TCR) engagement transduces biochemical signals through a protein-protein interaction (PPI) network that dictates dichotomous cell fate decisions. It remains unclear how signal specificity is communicated, instructing either positive selection to advance cell differentiation or death by negative selection. Early signal discrimination might occur by PPI signatures differing qualitatively (customized, unique PPI combinations for each signal), quantitatively (graded amounts of a single PPI series), or kinetically (speed of PPI pathway progression). Using a novel PPI network analysis, we found that early TCR-proximal signals distinguishing positive from negative selection appeared to be primarily quantitative in nature. Furthermore, the signal intensity of this PPI network was used to find an antigen dose that caused a classic negative selection ligand to induce positive selection of conventional αβ T cells, suggesting that the quantity of TCR triggering was sufficient to program selection outcome. Because previous work had suggested that positive selection might involve a qualitatively unique signal through CD3δ, we reexamined the block in positive selection observed in CD3δ⁰ mice. We found that CD3δ⁰ thymocytes were inhibited but capable of signaling positive selection, generating low numbers of MHC-dependent αβ T cells that expressed diverse TCR repertoires and participated in immune responses against infection. We conclude that the major role for CD3δ in positive selection is to quantitatively boost the signal for maximal generation of αβ T cells. Together, these data indicate that a quantitative network signaling mechanism through the early proximal TCR signalosome determines thymic selection outcome.

Profound intellectual disability caused by homozygous TRAPPC9 pathogenic variant in a man from Malta

Background

Intellectual disability is a complex multi‐faceted condition with diverse underlying etiologies. One rare form of intellectual disability is secondary to the loss of TRAPPC9, an activator of NF‐κB and a mediator of intracellular protein processing and trafficking. TRAPPC9 deficiency has been described in 48 patients with more than 15 pathologic variants.

Method

Clinical evaluation, magnetic resonance imaging, and whole‐exome sequencing were used to characterize the underlying cause of absent speech, restricted/repetitive behaviors, and worsening behavioral outbursts in 27‐year‐old man from Malta.

Results

Magnetic Resonance Imaging showed morphologic abnormalities, including global cerebral and cerebellar hypoplasia. Genetic analysis through Whole Exome Sequencing identified a homozygous deletion (c.568_574del) in TRAPPC9 resulting in a frameshift, premature stop codon, and ultimately a truncated protein (p.Trp190Argfs*95). In this case, the pathogenic variant was homozygous, identified in both of the parents without known consanguinity.

Conclusion

Given the phenotype and genotype consistent with a deficiency in TRAPPC9, it is likely that this patient represents a novel case of this rare genetic syndrome. Specifically, this case, in the context of 48 total reported patients, raises questions as to the geographic origin of the pathologic variant and optimal detection and therapeutic intervention for this condition.

NK cell defects in X-linked pigmentary reticulate disorder

X-linked reticulate pigmentary disorder (XLPDR, Mendelian Inheritance in Man #301220) is a rare syndrome characterized by recurrent infections and sterile multiorgan inflammation. The syndrome is caused by an intronic mutation in POLA1, the gene encoding the catalytic subunit of DNA polymerase-α (Pol-α), which is responsible for Okazaki fragment synthesis during DNA replication. Reduced POLA1 expression in this condition triggers spontaneous type I interferon expression, which can be linked to the autoinflammatory manifestations of the disease. However, the history of recurrent infections in this syndrome is as yet unexplained. Here we report that patients with XLPDR have reduced NK cell cytotoxic activity and decreased numbers of NK cells, particularly differentiated, stage V, cells (CD3^–CD56^dim). This phenotype is reminiscent of hypomorphic mutations in MCM4, which encodes a component of the minichromosome maintenance (MCM) helicase complex that is functionally linked to Pol-α during the DNA replication process. We find that POLA1 deficiency leads to MCM4 depletion and that both can impair NK cell natural cytotoxicity and show that this is due to a defect in lytic granule polarization. Altogether, our study provides mechanistic connections between Pol-α and the MCM complex and demonstrates their relevance in NK cell function.

X-linked reticulate pigmentary disorder is associated with functional NK cell defect due to abnormal lytic granule polarization.

NKG2D-DAP10 signaling recruits EVL to the cytotoxic synapse to generate F-actin and promote NK cell cytotoxicity

Natural killer (NK) cells eliminate abnormal cells through the release of cytolytic granule contents. In this process, NK cells must adhere to target cells through integrin-mediated adhesion, which is highly dependent on the generation of F-actin. Ena/VASP-like (EVL) is an actin regulatory protein previously shown to regulate integrin-mediated adhesion in other cell types, but its role in NK cell biology is not known. Herein, we show that EVL is recruited to the NK cell cytotoxic synapse and is required for NK cell cytotoxicity. Significantly, EVL is involved in the generation of F-actin at the cytotoxic synapse, antibody-stimulated spreading, and NK cell-target cell adhesion. EVL interacts with WASP (also known as WAS) and VASP and is required for localization of both proteins to the synapse. Recruitment of EVL to points of cellular activation occurs through the receptor NKG2D-DAP10 (also known as KLRK1 and HCST, respectively) via a binding site previously implicated in VAV1 and Grb2 recruitment. Taken together, this study implicates DAP10-mediated Grb2 and VAV1 signaling in the recruitment of an EVL-containing actin regulatory complex to the cytotoxic synapse where it can promote F-actin nucleation leading to NK cell-mediated killing.

VASP Regulates NK Cell Lytic Granule Convergence

NK cells eliminate viral-infected and malignant cells through a highly orchestrated series of cytoskeletal rearrangements, resulting in the release of cytolytic granule contents toward the target cell. Central to this process is the convergence of cytolytic granules to a common point, the microtubule-organizing center (MTOC), before delivery to the synapse. In this study, we show that vasodialator-stimulated phosphoprotein (VASP), an actin regulatory protein, localizes to the cytolytic synapse, but surprisingly, shows no impact on conjugate formation or synaptic actin accumulation despite being required for human NK cell-mediated killing. Interestingly, we also find that a pool of VASP copurifies with lytic granules and localizes with lytic granules at the MTOC. Significantly, depletion of VASP decreased lytic granule convergence without impacting MTOC polarization. Using the KHYG-1 cell line in which lytic granules are in a constitutively converged state, we find that either VASP depletion or F-actin destabilization promoted spreading of formerly converged granules. Our results demonstrate a novel requirement for VASP and actin polymerization in maintaining lytic granule convergence during NK cell-mediated killing.

Risk of Obstructive Sleep Apnea and Its Association with Cardiovascular and Noncardiac Vascular Risk in Patients with Rheumatoid Arthritis: A Population-based Study

OBJECTIVE

To define the incidence of obstructive sleep apnea (OSA) in patients with rheumatoid arthritis (RA) and determine whether OSA diagnosis predicts future cardiovascular disease (CVD) and noncardiac vascular events.

METHODS

Medical information pertaining to RA, OSA, CVD, and vascular diagnoses was extracted from a comprehensive medical record system for a geographically defined population of 813 patients previously diagnosed with RA and 813 age- and sex-matched comparator subjects.

RESULTS

The risk for OSA in persons with RA versus comparators was elevated, although not reaching statistical significance (HR 1.32, 95% CI 0.98-1.77; p = 0.07). Patients with RA were more likely to be diagnosed with OSA if they had traditional risk factors for OSA, including male sex, current smoking status, hypertension, diabetes, dyslipidemia, and increased body mass index. Features of RA disease associated with OSA included large joint swelling and joint surgery. Patients with RA with decreased renal function were also at higher risk of OSA. The increased risk of overall CVD among patients with RA who have OSA was similar to the increased CVD risk associated with OSA in the comparator cohort (interaction p = 0.86). OSA diagnosis was associated with an increased risk of both CVD (HR 1.9, 95% CI 1.08-3.27), and cerebrovascular disease (HR 2.4, 95% CI 1.14-5.26) in patients with RA.

CONCLUSION

Patients with RA may be at increased risk of OSA secondary to both traditional and RA-related risk factors. Diagnosis with OSA predicts future CVD in RA and may provide an opportunity for CVD intervention.

Novel Assessment of Interstitial Lung Disease Using the "Computer-Aided Lung Informatics for Pathology Evaluation and Rating" (CALIPER) Software System in Idiopathic Inflammatory Myopathies

PURPOSE

To evaluate the correlation between measurements from quantitative thoracic high-resolution CT (HRCT) analysis with "Computer-Aided Lung Informatics for Pathology Evaluation and Rating" (CALIPER) software and measurements from pulmonary function tests (PFTs) in patients with idiopathic inflammatory myopathies (IIM)-associated interstitial lung disease (ILD).

METHODS

A cohort of patients with IIM-associated ILD seen at Mayo Clinic was identified from medical record review. Retrospective analysis of HRCT data and PFTs at baseline and 1 year was performed. The abnormalities in HRCT were quantified using CALIPER software.

RESULTS

A total of 110 patients were identified. At baseline, total interstitial abnormalities as measured by CALIPER, both by absolute volume and by percentage of total lung volume, had a significant negative correlation with diffusing capacity for carbon monoxide (DLCO), total lung capacity (TLC), and oxygen saturation. Analysis by subtype of interstitial abnormality revealed significant negative correlations between ground glass opacities (GGO) and reticular density (RD) with DLCO and TLC. At one year, changes of total interstitial abnormalities compared with baseline had a significant negative correlation with changes of TLC and oxygen saturation. A negative correlation between changes of total interstitial abnormalities and DLCO was also observed, but it was not statistically significant. Analysis by subtype of interstitial abnormality revealed negative correlations between changes of GGO and RD and changes of DLCO, TLC, and oxygen saturation, but most of the correlations did not achieve statistical significance.

CONCLUSION

CALIPER measurements correlate well with functional measurements in patients with IIM-associated ILD.

Malignancy incidence in patients with psoriatic arthritis: a comparison cohort-based incidence study

Malignancy is a major cause of death in patients with inflammatory disease. The risk of individual malignancies is altered in some inflammatory diseases, such as rheumatoid arthritis and psoriasis. This study aimed to examine malignancy incidence in patients with psoriatic arthritis (PsA), a related inflammatory disease. Institutional cancer registry and medical record linkage systems were retrospectively reviewed in a population-based incidence cohort of 217 patients with PsA and 434 age- and sex-matched comparators. Malignancy rates were compared using adjusted Cox models. Incidence of overall malignancy (excluding NMSC; hazard ratio (HR) 1.64; 95 % confidence interval (CI) 1.03-2.61) and breast cancer (HR 3.59; 95 % CI 1.22-10.61), but not NMSC (HR 1.23; 95 % CI 0.72-2.09), were significantly elevated in the PsA cohort. Age and female sex were similar predisposing risk factors in both cohorts. The overall incidence of malignancy, as well as the risk of breast cancer, was higher in patients with PsA than in the general population.

Cardiovascular risk profile at the onset of psoriatic arthritis: a population-based cohort study

OBJECTIVE

The role of cardiovascular disease (CVD) risk factors in psoriatic arthritis (PsA) is poorly understood. We examined the prevalence of CVD risk factors at initial onset of PsA and compared the observed incidence of CVD events with that predicted by the Framingham Risk Score (FRS) to determine its applicability in this patient population.

METHODS

A population-based incidence cohort of 158 patients with PsA who fulfilled Classification of Psoriatic Arthritis criteria for PsA in 1989-2008 was assembled. Medical records were reviewed to ascertain CVD risk factors and CVD events. Future risk of CVD was estimated using the FRS algorithm.

RESULTS

Mean age was 43.4 years (range 19-74 years), 61% were men, and 44% were obese (body mass index ≥30 kg/m(2) ). Fifty-four patients (34%) presented with ≥2 CVD risk factors at PsA incidence. Among 126 patients ages ≥30 years at PsA incidence with no prior history of CVD, 33% had an FRS ≥10%, with 11% having an FRS ≥20%, and 18 experienced a CVD event in the first 10 years of disease duration. The 10-year cumulative incidence of CVD events was 17% (95% confidence interval [95% CI] 10%-24%), almost twice as high as the predicted incidence based on the FRS (standardized incidence ratio 1.80, 95% CI 1.14-2.86; P = 0.012).

CONCLUSION

The majority of newly diagnosed PsA patients have a >10% risk of CVD within 10 years of PsA incidence. The CVD risk in these patients is higher than expected and underestimated by the FRS.

Slow angled-descent forepaw grasping (SLAG): an innate behavioral task for identification of individual experimental mice possessing functional vision

Background

There is significant interest in the generation of improved assays to clearly identify experimental mice possessing functional vision, a property that could qualify mice for inclusion in behavioral and neuroscience studies. Widely employed current methods rely on mouse responses to visual cues in assays of reflexes, depth perception, or cognitive memory. However, commonly assessed mouse reflexes can sometimes be ambiguous in their expression, while depth perception assays are sometimes confounded by variation in anxiety responses and exploratory conduct. Furthermore, in situations where experimental groups vary in their cognitive memory capacity, memory assays may not be ideal for assessing differences in vision.

Results

We have optimized a non-invasive behavioral assay that relies on an untrained, innate response to identify individual experimental mice possessing functional vision: slow angled-descent forepaw grasping (SLAG). First, we verified that SLAG performance depends on vision and not olfaction. Next, all members of an age-ranged cohort of 158 C57BL/6 mice (57 wild-type, 101 knockout, age range 44–241 days) were assessed for functional vision using the SLAG test without training or conditioning. Subjecting the population to a second innate behavioral test, Dark Chamber preference, corroborated that the functional vision assessment of SLAG was valid.

Conclusions

We propose that the SLAG assay is immediately useful to quickly and clearly identify experimental mice possessing functional vision. SLAG is based on a behavioral readout with a significant innate component with no requirement for training. This will facilitate the selection of mice of known sighted status in vision-dependent experiments that focus on other types of behavior, neuroscience, and/or cognitive memory.

Human papillomavirus type 16 E6 and E 7 proteins alter NF-kB in cultured cervical epithelial cells and inhibition of NF-kB promotes cell growth and immortalization

The NF-kB family of transcription factors regulates important biological functions including cell growth, survival and the immune response. We found that Human Papillomavirus type 16 (HPV-16) E7 and E6/E7 proteins inhibited basal and TNF-alpha-inducible NF-kB activity in human epithelial cells cultured from the cervical transformation zone, the anatomic region where most cervical cancers develop. In contrast, HPV-16 E6 regulated NF-kB in a cell type- and cell growth-dependent manner. NF-kB influenced immortalization of cervical cells by HPV16. Inhibition of NF-kB by an IkB alpha repressor mutant increased colony formation and immortalization by HPV-16. In contrast, activation of NF-kB by constitutive expression of p65 inhibited proliferation and immortalization. Our results suggest that inhibition of NF-kB by HPV-16 E6/E7 contributes to immortalization of cells from the cervical transformation zone.

Inhibition of the epidermal growth factor receptor by erlotinib prevents immortalization of human cervical cells by Human Papillomavirus type 16

The Human Papillomavirus type-16 (HPV-16) E6 and E7 oncogenes are selectively retained and expressed in cervical carcinomas, and expression of E6 and E7 is sufficient to immortalize human cervical epithelial cells. Expression of the epidermal growth factor receptor (EGFR) is often increased in cervical dysplasia and carcinoma, and HPV oncoproteins stimulate cell growth via the EGFR pathway. We found that erlotinib, a specific inhibitor of EGFR tyrosine kinase activity, prevented immortalization of cultured human cervical epithelial cells by the complete HPV-16 genome or the E6/E7 oncogenes. Erlotinib stimulated apoptosis in cells that expressed HPV-16 E6/E7 proteins and induced senescence in a subpopulation of cells that did not undergo apoptosis. Since immortalization by HPV E6/E7 is an important early event in cervical carcinogenesis, the EGFR is a potential target for chemoprevention or therapy in women who have a high risk for cervical cancer.

Personal computers and process writing: a written language intervention for deaf children

This study was concerned with the effectiveness of word processing as a written language intervention for primary-age deaf children. Subjects were 14 children in two primary school deaf-unit classes matched in terms of age, gender, and degree of hearing loss. A quasi-experimental design incorporating multiple-group baselines with pre- and post-tests enable all subjects to receive the intervention while maintaining experimental control. Samples of children's written language were collected at the end of each phase in the study. Experienced teachers of deaf children rated five dimensions of the quality of the written language samples, while a speech and language therapist judged other linguistic qualities of the writing. Significant improvements in quality ratings over the course of the study indicated that the word processing intervention had led to improvements in the children's written language skills. These results confirm the effectiveness of word processing as an adjunct to the process writing approach to written language instruction for deaf children.

Children's attitudes toward peers with intellectual disability

The policy of inclusion (mainstreaming) of children with an intellectual disability in regular schools has raised questions about the extent to which 'true' integration is possible. One important aspect of integration is social acceptance by the regular class children. The purpose of this study was to determine the attitudes of children in primary and intermediate classrooms towards children with an intellectual disability housed in satellite classrooms at public schools. Teachers in the satellite classrooms completed a school integration questionnaire. Attitudes towards and the social distance afforded children in satellite classrooms were relatively positive across all children, especially girls. In particular, attitudes were more positive in schools which had more vigorous administrative policies concerning academic and social integration. The results are discussed in terms of current mainstreaming policies for children with intellectual disabilities.

Nutritional intakes of socioculturally mentally retarded children vs. children of low and average socioeconomic status

The adequacy of dietary intakes of socioculturally mentally retarded children, nonretarded children of low socioeconomic status (SES), and nonretarded children of average SES were studied. The socioculturally retarded children showed significantly lower daily intakes of almost all basic nutritional substances than did the nonretarded children in either the low- or average-SES groups. We also found that the socioculturally retarded group's intake of iron, calcium, thiamine, and ascorbic acid was below National Academy of Sciences/National Research Council recommended daily allowance levels, a finding that did not occur for either of the other groups. Although the precise developmental significance of these findings is somewhat unclear, it seems prudent to incorporate a focus on dietary provisions (as well as on other home conditions) in future intervention programs for children at high-risk for sociocultural mental retardation.

Eye movements and conservation acceleration in mildly retarded children

Thirty mildly retarded elementary-school children, 15 of whom had received perceptual/attentional training, were tested on four Piagetian conservation tasks (number, length, and continuous quantity solid/liquid) presented on 16 mm movie film with taped instructions. Eye movements were recorded during the response period for each task. Subsequent analyses of eye-movement patterns showed clear differences between the training and control groups. Trained conservers showed more visual exploratory activity and less perceptual centration than control group subjects. Moreover the eye-movement patterns of trained conservers closely approximated those shown by natural (i.e., untrained) retarded conservers in a previous study. The findings were discussed in terms of possible cognitive structural changes resulting from training and possible cognitive structural differences between mildly retarded and nonretarded children.