Atypical Errors Research Articles

Usefulness of investigating error profiles in diagnosis of naming impairments.

Word-retrieval difficulties are commonly experienced by people with aphasia (PwA) and also by typically ageing persons. Differentiation between true naming impairments and naming difficulties found in healthy persons may, therefore, be challenging. To investigate the extent to which the Maltese adaptation of the Boston Naming Test (BNT) can identify people with lexical retrieval difficulties and to differentiate them from people with unimpaired word finding. Naming performance of a group of PwA was compared with the performance of a control group. Performance on the Maltese adaptation of the BNT was investigated in terms of scores, range of scores and error profiles of the two groups. All PwA scored below the mean score of the controls, indicating that persons who scored above the mean score may be considered as unimpaired. However, a number of the controls obtained very low scores that overlapped with the scores obtained by the PwA. This indicated that scores alone cannot be used to differentiate between impaired and unimpaired people. Some types of errors were only produced by people with impaired naming, and did not appear at all in error profiles of unimpaired individuals. Mild-moderate anomic impairments may be missed if naming impairment is assessed and diagnosed using a cut-off score. In order to differentiate between people with impaired and unimpaired naming, it is necessary to look at error profiles, apart from the number of errors, as the presence of atypical errors may be an important indicator of naming impairments.

Speech abilities in preschool children with speech sound disorder with and without co-occurring language impairment.

The authors compared preschool children with co-occurring speech sound disorder (SSD) and language impairment (LI) to children with SSD only in their numbers and types of speech sound errors. In this post hoc quasi-experimental study, independent samples t tests were used to compare the groups in the standard score from different tests of articulation/phonology, percent consonants correct, and the number of omission, substitution, distortion, typical, and atypical error patterns used in the production of different wordlists that had similar levels of phonetic and structural complexity. In comparison with children with SSD only, children with SSD and LI used similar numbers but different types of errors, including more omission patterns ( p < .001, d = 1.55) and fewer distortion patterns ( p = .022, d = 1.03). There were no significant differences in substitution, typical, and atypical error pattern use. Frequent omission error pattern use may reflect a more compromised linguistic system characterized by absent phonological representations for target sounds (see Shriberg et al., 2005). Research is required to examine the diagnostic potential of early frequent omission error pattern use in predicting later diagnoses of co-occurring SSD and LI and/or reading problems.

Validation of the Intelligibility in Context Scale as a screening tool for preschoolers in Hong Kong

The Intelligibility in Context Scale (ICS) is a parent report questionnaire for assessing children’s speech intelligibility. The original version was developed in English and was based on Environmental Factors identified within the International Classification of Functioning, Disability and Health-Children and Youth Version (ICF-CY). The ICS has been translated into over 30 languages, including Traditional Chinese (ICS-TC). The aims of the current study were to examine the psychometric properties of the ICS-TC with Cantonese-speaking parent--child dyads and to identify speech measures that were more sensitive to the ICS-TC ratings. A total of 72 Cantonese-speaking preschoolers with (n = 39) and without speech sound disorders (SSD; n = 33) were recruited. Native Cantonese-speaking parents completed the ICS-TC independently. The measure showed good internal consistency and test–retest reliability. Correlations with speech performance on the Hong Kong Cantonese Articulation Test (HKCAT), and significant difference in ICS-TC mean scores between the two groups provided preliminary support for the validity of ICS-TC and suggested that ICS-TC can differentiate between children with and without SSD with a large effect size of d = 0.74. The optimal cutoff was estimated using Receiver Operative Characteristic (ROC) curve analysis, giving a sensitivity of 0.70 and specificity of 0.59. ICS-TC mean scores showed a positive correlation with the percentage of initial consonants correct and negative correlation with frequency of atypical errors, and both were moderate in strength. Given the satisfactory psychometric properties of ICS-TC, it may be a valuable clinical tool for screening Cantonese-speaking preschool children’s intelligibility.

Effect of prenatal maternal depression on early speech sound acquisition: A preliminary study

ObjectiveSpeech sound disorders (SSD) are the most prevalent childhood communication disorders. Many cases of SSD have an unknown origin. The study investigated the effect of prenatal maternal depression on the offspring's speech sound production.MethodData from 26 mother–child dyads were included in the study. Prenatal maternal depression was assessed by a validated questionnaire during the third trimester of pregnancy. Speech sound production ability was assessed in terms of the number of atypical (non-developmental) speech errors produced in a standardized speech assessment when the children were 2-years-old.ResultsSix of the mothers’ questionnaires suggested depression, whereas 20 were within normal limits. Hierarchical multiple regression analyses indicated that prenatal depression uniquely accounted for 30.8% of the variance in speech sound acquisition after controlling for the child's sex and postnatal maternal depression level.ConclusionsMaternal prenatal depression was significantly associated with more atypical speech errors in the offspring at 2 years. The current findings contribute to understanding the etiology of SSD with unknown origin. At a clinical level, prenatal depression could be taken as a risk factor for SSD.

Persistent consequences of atypical early number concepts

How does symbolic number knowledge performance help identify young children at risk for poor mathematics achievement outcomes? In research and practice, classification of mathematics learning disability (MLD, or dyscalculia) is typically based on composite scores from broad measures of mathematics achievement. These scores do predict later math achievement levels, but do not specify the nature of math difficulties likely to emerge among students at greatest risk for long-term mathematics failure. Here we report that gaps in 2nd and 3rd graders' number knowledge predict specific types of errors made on math assessments at Grade 8. Specifically, we show that early whole number misconceptions predict slower and less accurate performance, and atypical computational errors, on Grade 8 arithmetic tests. We demonstrate that basic number misconceptions can be detected by idiosyncratic responses to number knowledge items, and that when such misconceptions are evident during primary school they persist throughout the school age years, with variable manifestation throughout development. We conclude that including specific qualitative assessments of symbolic number knowledge in primary school may provide greater specificity of the types of difficulties likely to emerge among students at risk for poor mathematics outcomes.

Preschool Speech Error Patterns Predict Articulation and Phonological Awareness Outcomes in Children With Histories of Speech Sound Disorders

To determine if speech error patterns in preschoolers with speech sound disorders (SSDs) predict articulation and phonological awareness (PA) outcomes almost 4 years later. Twenty-five children with histories of preschool SSDs (and normal receptive language) were tested at an average age of 4;6 (years;months) and were followed up at age 8;3. The frequency of occurrence of preschool distortion errors, typical substitution and syllable structure errors, and atypical substitution and syllable structure errors was used to predict later speech sound production, PA, and literacy outcomes. Group averages revealed below-average school-age articulation scores and low-average PA but age-appropriate reading and spelling. Preschool speech error patterns were related to school-age outcomes. Children for whom >10% of their speech sound errors were atypical had lower PA and literacy scores at school age than children who produced <10% atypical errors. Preschoolers who produced more distortion errors were likely to have lower school-age articulation scores than preschoolers who produced fewer distortion errors. Different preschool speech error patterns predict different school-age clinical outcomes. Many atypical speech sound errors in preschoolers may be indicative of weak phonological representations, leading to long-term PA weaknesses. Preschoolers' distortions may be resistant to change over time, leading to persisting speech sound production problems.

Computerized analysis of error patterns in digit span recall

We analyzed error patterns during digit span (DS) testing in four experiments. In Experiment 1, error patterns analyzed from a community sample of 427 subjects revealed strong primacy and recency effects. Subjects with shorter DSs showed an increased incidence of transposition errors in comparison with other error types and a greater incidence of multiple errors on incorrect trials. Experiment 2 investigated 46 young subjects in three test sessions. The results replicated those of Experiment 1 and demonstrated that error patterns of individual subjects were consistent across repeated test administrations. Experiment 3 investigated 40 subjects from Experiment 2 who feigned symptoms of traumatic brain injury (TBI) with 80% of malingering subjects producing digit spans in the abnormal range. A digit span malingering index (DSMI) was developed to detect atypical error patterns in malingering subjects. Overall, 59% of malingering subjects with abnormal digit spans showed DSMIs in the abnormal range and DSMI values correlated significantly with the magnitude of malingering. Experiment 4 compared 29 patients with TBI with a new group of 38 control subjects. The TBI group showed significant reductions in digit span. Overall, 32% of the TBI patients showed DS abnormalities and 11% showed abnormal DSMIs. Computerized error-pattern analysis improves the sensitivity of DS assessment and can assist in the detection of malingering.

Speech production deficits in early readers: predictors of risk.

Speech problems and reading disorders are linked, suggesting that speech problems may potentially be an early marker of later difficulty in associating graphemes with phonemes. Current norms suggest that complete mastery of the production of the consonant phonemes in English occurs in most children at around 6–7 years. Many children enter formal schooling (kindergarten) around 5 years of age with near-adult levels of speech production. Given that previous research has shown that speech production abilities and phonological awareness skills are linked in preschool children, we set out to examine whether this pattern also holds for children just beginning to learn to read, as suggested by the critical age hypothesis. In the present study, using a diverse sample, we explored whether expressive phonological skills in 92 5-year-old children at the beginning and end of kindergarten were associated with early reading skills. Speech errors were coded according to whether they were developmentally appropriate, position within the syllable, manner of production of the target sounds, and whether the error involved a substitution, omission, or addition of a speech sound. At the beginning of the school year, children with significant early reading deficits on a predictively normed test (DIBELS) made more speech errors than children who were at grade level. Most of these errors were typical of kindergarten children (e.g., substitutions involving fricatives), but reading-delayed children made more of these errors than children who entered kindergarten with grade level skills. The reading-delayed children also made more atypical errors, consistent with our previous findings about preschoolers. Children who made no speech errors at the beginning of kindergarten had superior early reading abilities, and improvements in speech errors over the course of the year were significantly correlated with year-end reading skills. The role of expressive vocabulary and working memory were also explored, and appear to account for some of these findings.

Behaviour of short-circuit frequency and duration time and electrical conductivity during arc re-ignition in SMAW (AC) with E6013 electrodes

The objective of this work is to evaluate the behaviour of short-circuit frequency and duration time and electrical conductivity during arc re-ignition in the shielded metal arc welding process with alternating current and E6013 electrodes. The non-parametric statistical analysis guarantees robust processing of the data, reducing the influence of atypical values and errors derived from the use of approximations to well-known continuous distributions. The median and the median absolute deviation (MAD) with respect to the median of the data are the localization and dispersion estimators used, respectively. The electrode set at 160 A shows a better stability in metal transference, given for the lowest value of MAD for the short-circuit period (39.36 ms), and the MAD of the short-circuit duration (1.43 ms), according to the presence of a major electrical conductivity during the arc re-ignition (1766.17 × 10− 3 S s− 1).

Lateral Intent Error’s Impact on Aircraft Prediction

The lateral deviation between the air traffic automation’s known horizontal route of flight and the actual aircraft position is due to the typical navigation and surveillance errors, as well as the larger atypical errors that are mainly caused by purposeful changes in the route of flight that are not updated. The paper presents large data analyses of the ground automation systems of the United States and Europe, indicating errors from 20 to 30 nautical miles are common, while airborne Australian and more samples in the United States had errors from 100 to 800 times smaller. Further analysis illustrated the direct impact these errors have on safety critical separation management functions. It was concluded that airborne derived data via Automatic Dependent Surveillance Contract reports offer a major opportunity to improve the ground-based automation functions.

Cognitive flexibility in children with and without speech disorder

Most children's speech difficulties are `functional' (i.e. no known sensory, motor or intellectual deficits). Speech disorder may, however, be associated with cognitive deficits considered core abilities in executive function: rule abstraction and cognitive flexibility. The study compares the rule abstraction and cognitive flexibility of children with speech disorder and typically developing controls. Three groups of five-year-old children (typically developing, consistent atypical speech disorder and inconsistent speech disorder) were assessed on the Flexible Item Selection Test (Jacques and Zelazo, 2001). Children were shown a set of three cards and asked to select two that matched on one dimension (selection 1: abstraction). Children were then asked to select a different pair of cards that matched on another dimension (selection 2: flexibility). The children with consistent atypical speech disorder performed worse than the other two groups on selections 1 and 2. The children with an inconsistent speech disorder performed similarly to their typically developing peers. Children who use consistent atypical error patterns have difficulties with rule abstraction and flexibility that are not confined to the linguistic system. The results are discussed in terms of the deficits underlying different types of speech disorders.

Error Monitoring in College Students with Attention-Deficit/Hyperactivity Disorder

Recent error-related event-related potential (ERP) studies suggest that children with attention-deficit/hyperactivity disorder (ADHD) display deficits in error monitoring compared to control children. Information regarding error monitoring deficit in adults with ADHD, however, is scarce. We investigated error monitoring in a sample of college students with ADHD and compared them to their control peers. In addition to error (-related) negativity (Ne/ERN) and error positivity (Pe), we examined behavioral performance such as reaction time (RT) as well as self-reported monitoring behaviors in daily-life situations. Thirty-two college students with no known disorders and 36 college students with ADHD between 18 and 30 years of age participated in this study. Results showed that college students with ADHD were slower in their RT and displayed more RT variability. College students with ADHD also demonstrated significantly smaller Ne/ERN amplitude and shorter Ne/ERN latency compared to control students. There were, however, no significant group differences in either Pe amplitude or Pe latency. With self-reported monitoring behaviors, ADHD students reported significantly more difficulties in both the Self-Monitor and Task Monitor scales of the Behavioral Rating Inventory of Executive Function – Adult Version (BRIEF-A) compared to control students. Collectively, these results suggest that college students with ADHD have atypical error monitoring as measured by brain processing, behavioral performance, and self-report.

Developing a size indicator for fish populations

Monitoring temporal and/or spatial variations in fish size-at-age data can often provide fisheries managers with important information about the status of fish stocks and therefore help them identify necessary changes in management policies. However, due to the multivariate nature of size-at-age data, commonly used single-age-based approaches ignore covariance between sizes of different age groups. Different results may therefore be derived when evaluating temporal variations using different age groups for the comparison. The possibility of atypical errors in size-at-age data due to ageing and measurement errors further complicates the comparison. We propose a two-step approach for developing an indicator for monitoring temporal and/or spatial variation in size-at-age data. A robust approach, minimum volume ellipsoid analysis, is used to identify possible outliers in size-at-age data. Then a weighted principal component analysis is applied to the data with the identified outliers down-weighted. An indicator is defined from the resultant principal components for monitoring temporal/spatial variations in size-at-age data. We illustrate the proposed approach with size-at-age data for cod (Gadus morhua) in the northwest Atlantic, NAFO subdivision 3Ps. The overall size-at-age indicator identified shows that the pre-1980 year classes tend to have a much higher size-at-age than the post-1980 year classes.

Two-year-olds' phonological acquisition: Normative data

The study reported evaluated an assessment of phonology for 2-year-olds to establish normative data and determine if early identification of children with speech difficulties is possible. The study evaluated 62 2-year-old children on the Toddler Phonology Test (TPT). Children produced 32 words, spontaneously or in imitation. Ten of the children were assessed three times, on the third occasion, when they had reached 3 years, on another phonological assessment. The data indicated that older children performed better than younger children on quantitative measures. Girls and boys performed equally well. Their phonetic repertoires were missing some fricatives and all affricates, as well as /r/. Consistently used error patterns identified included cluster reduction, final consonant deletion, stopping, fronting, weak syllable, deletion, gliding and deaffrication. Correlation analyses indicated that performance at the first assessment on the TPT indicated performance on subsequent assessments. While quantitative data was not a reliable predictive indicator of speech disorder, qualitative analysis of error types was predictive, with children who made many atypical errors at 2 years being diagnosed as phonologically disordered at 3 years. The findings provide initial evidence that direct formal assessment of 2-year-old phonology is possible.

Developing robust frequentist and Bayesian fish stock assessment methods

AbstractErrors in fitting models to data are usually assumed to follow a normal (or log normal) distribution in fisheries. This assumption is usually used in formulating likelihood functions often required in frequentist and Bayesian stock assessment modelling. Fisheries data are commonly subject to atypical errors, resulting in outliers in stock assessment modelling. Because most stock assessment models are nonlinear and contain multiple variables, it is difficult, if not impossible, to identify outliers by plotting fisheries data alone. Commonly used normal distribution‐based frequentist and Bayesian stock assessment methods are sensitive to outliers, resulting in biased estimates of model parameters that are vital in defining the dynamics of fish stocks and evaluating alternative strategies for fisheries management. Because of the high likelihood of having outliers in fisheries data, frequentist or Bayesian methods robust to outliers are more desirable in fisheries stock assessment. This study reviews three approaches that can be used to develop robust frequentist or Bayesian stock assessment methods. Using simulated fisheries as examples, we demonstrate how these approaches can be used to develop the frequentist and Bayesian stock assessment approaches that are robust to outliers in fisheries data and compare the robust approaches with the commonly used normal distribution‐based approach. The proposed robust approaches provide alternative ways to developing frequentist or Bayesian stock assessment methods.

Quality of fisheries data and uncertainty in stock assessment

The quality of fisheries data has great impacts on the quality of stock assessment, and thus fisheries management. In this paper, using a case study I evaluate the impacts of two types of error, biased error and atypical error, that can negatively affect the quality of fisheries data in stock assessment. These errors are commonly associated with fisheries data, and assumptions on their sources and statistical properties can have great impacts on the outcome of stock assessment. Although the sources and statistical properties of these errors differed, both of them could result in errors in stock assessment if estimation methods are not appropriate. Different statistical approaches used in fitting models differ in their robustness with respect to errors of different statistical properties in data. This study showed the importance of evaluating the quality of input data and the possibility of developing an approach that is robust to errors in data. Considering the likelihood of fisheries data being affected by errors of different statistical properties, I suggest that the robustness of a stock assessment be evaluated with respect to data quality.

A Prospective Longitudinal Study of Phonological Development in Late Talkers.

This study involved prospective longitudinal data on 5 late talkers to provide information about the course of phonological development in order to identify possible predictors of delayed versus deviant development. Five children (3 boys, 2 girls) were identified as late talkers and divided into a younger group and an older group. Each child was followed monthly for 10 to 12 months (22-33 months for the younger group and 30-42 months for the older group). Two types of monthly language samples (free play and elicited) were obtained to describe the individual courses of phonological development for each child. Independent and relational analyses were completed at each age to describe word-initial and word-final phonetic inventories, syllable structure, syllable diversity, percentage of consonants correct (PCC), sound variability, and error patterns. The results indicated that 3 of the children resolved their late onset of speech by 33 to 35 months of age. In addition to quantitative factors, (e.g., limited phonetic inventory, lower PCC, and more sound errors), qualitative variables (e.g., atypical error patterns, greater sound variability, and slower rate of resolution) also were identified as potential markers of long-term phonological delay. This study provides information to clinicians so they can identify those children who are less likely to resolve their late onset of phonological development without direct intervention. Procedures are described for assessing early linguistic behaviors that incorporate independent and relational analyses on more extensive speech samples (elicited and free play). From these analyses, clinicians can examine quantitative and qualitative variables to differentiate phonological delay from deviance.

Phonologically Disordered German-Speaking Children

Speech sound disorders affect more children than any other developmental communication disorder and are associated with long-term social and academic difficulties. The diversity of presenting symptoms has resulted in the need for classifying subgroups of speech disorders. Research on English-speaking children suggests that there are four types of surface speech error patterns (B. Dodd, 1995): articulation disorder (e.g., lisp); delay (i.e., normal developmental patterns that are inappropriate for chronological age); consistent use of atypical error patterns (e.g., deletion of all initial consonants); and inconsistent pronunciation of the same lexical items. Classification typologies should be language independent. This study investigated whether the same four subgroups, in similar proportions, would be found in German-speaking children who had disordered speech. A total of 110 monolingual German-speaking children, aged 2 years 7 months to 7 years 7 months, participated in the study. They had been referred for assessment of a suspected speech disorder. The results supported the subgroup classification, providing evidence for the universal character of speech disorders. One significant difference was the relatively high proportion of children classified as having an articulation disorder. This was explained by the uncertainty regarding a lisp as a disorder in German, since it is also found in up to 40% of normally developing children of the same age. The theoretical and clinical implications of the findings are discussed.

Origins of Paraphasias in Deep Dysphasia: Testing the Consequences of a Decay Impairment to an Interactive Spreading Activation Model of Lexical Retrieval

This study investigates an account of atypical error patterns within the framework of an interactive spreading activation model. Martin and Saffran (1992) described a patient, NC, whose error pattern was unusual for the occurrence of higher rates of form-related than meaning-related word substitutions in naming and the production of semantic errors in repetition. They proposed that NC′s error pattern could be accounted for by a pathologically rapid decay of primed nodes in the semantic-lexical-phonological network that shifts the probabilities of error outcome in lexical retrieval. In the present study, Martin and Saffran′s account was tested and supported in a series of simulations that reproduce essential features of NC′s lexical error pattern in naming and repetition. Also described here are the results of a longitudinal study of NC′s naming and repetition, which revealed a shift in relative lexical error rates toward a qualitatively normal pattern. This change in error pattern was simulated by assuming that recovery reflects resolution of the rapid decay rate toward normal levels. The patient data and computational studies are discussed in terms of their significance for the understanding of aphasic impairments and their implications for models of lexical retrieval.

Phonologic Error Distributions in the Iowa-Nebraska Articulation Norms Project

The errors on consonant singletons made by children in the Iowa-Nebraska Articulation Norms Project (Smit, Hand, Freilinger, Bernthal, & Bird, 1990) were tabulated by age range and frequency. The prominent error types can usually be described as phonological processes, but there are other common errors as well, especially distortions of liquids and fricatives. Moreover, some of the relevant phonological processes appear to be restricted in the range of consonants or word-positions to which they apply. A metric based on frequency of use is proposed for determining that an error type is or is not atypical. Changes in frequency of error types over the age range are examined to determine if certain atypical error types are likely to be developmental, that is, likely to self-correct as the child matures. Finally, the clinical applications of these data for evaluation and intervention are explored.