MSKI-RADS: An MRI-based Musculoskeletal Infection Reporting and Data System for the Diagnosis of Extremity Infections.

Background Current terms used to describe the MRI findings for musculoskeletal infections are nonspecific and inconsistent. Purpose To develop and validate an MRI-based musculoskeletal infection classification and scoring system. Materials and Methods In this retrospective cross-sectional internal validation study, a Musculoskeletal Infection Reporting and Data System (MSKI-RADS) was designed. Adult patients with radiographs and MRI scans of suspected extremity infections with a known reference standard obtained between June 2015 and May 2019 were included. The scoring categories were as follows: 0, incomplete imaging; I, negative for infection; II, superficial soft-tissue infection; III, deeper soft-tissue infection; IV, possible osteomyelitis (OM); V, highly suggestive of OM and/or septic arthritis; VI, known OM; and NOS (not otherwise specified), nonspecific bone lesions. Interreader agreement for 20 radiologists from 13 institutions (intraclass correlation coefficient [ICC]) and true-positive rates of MSKI-RADS were calculated and the accuracy of final diagnoses rendered by the readers was compared using generalized estimating equations for clustered data. Results Among paired radiographs and MRI scans from 208 patients (133 male, 75 female; mean age, 55 years ± 13 [SD]), 20 were category I; 34, II; 35, III; 30, IV; 35, V; 18, VI; and 36, NOS. Moderate interreader agreement was observed among the 20 readers (ICC, 0.70; 95% CI: 0.66, 0.75). There was no evidence of correlation between reader experience and overall accuracy (P = .94). The highest true-positive rate was for MSKI-RADS I and NOS at 88.7% (95% CI: 84.6, 91.7). The true-positive rate was 73% (95% CI: 63, 80) for MSKI-RADS V. Overall reader accuracy using MSKI-RADS across all patients was 65% ± 5, higher than final reader diagnoses at 55% ± 7 (P < .001). Conclusion MSKI-RADS is a valid system for standardized terminology and recommended management of imaging findings of peripheral extremity infections across various musculoskeletal-fellowship-trained reader experience levels. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Schweitzer in this issue.

Learning verbs in English and Korean: The roles of word order and argument drop.

To learn new words, particularly verbs, child learners have been shown to benefit from the linguistic contexts in which the words appear. However, cross-linguistic differences affect how this process unfolds. One previous study found that children's abilities to learn a new verb differed across Korean and English as a function of the sentence in which the verb occurred (Arunachalam et al., 2013). The authors hypothesized that the properties of word order and argument drop, which vary systematically in these two languages, were driving the differences. In the current study, we pursued this finding to ask if the difference persists later in development, or if children acquiring different languages come to appear more similar as their linguistic knowledge and learning capacities increase. Preschool-aged monolingual English learners (N = 80) and monolingual Korean learners (N = 64) were presented with novel verbs in contexts that varied in word order and argument drop and accompanying visual stimuli. We assessed their learning by measuring accuracy in a forced-choice pointing task, and we measured eye gaze during the learning phase as an indicator of the processes by which they mapped the novel verbs to meaning. Unlike previous studies which identified differences between English and Korean learning 2-year-olds in a similar task, our results revealed similarities between the two language groups with these older preschoolers. We interpret our results as evidence that over the course of early childhood, children become adept at learning from a larger variety of contexts, such that differences between learners of different languages are attenuated.

Parental tuning of language input to autistic and nonspectrum children.

Caregivers' language input supports children's language development, and it is often tuned to the child's current level of skill. Evidence suggests that parental input is tuned to accommodate children's expressive language levels, but accommodation to receptive language abilities is less understood. In particular, little is known about parental sensitivity to children's abilities to process language in real time. Compared to nonspectrum children, children on the spectrum are slower to process language. In this study, we ask: Do parents of autistic children and those of nonspectrum children tune their language input to accommodate children's different language processing abilities? Children with and without a diagnosis of autism (ages 2-6 years, N = 35) and their parents viewed a display of six images, one of which was the target. The parent labeled the target to direct the child's attention to it. We first examined children's language processing abilities by assessing their latencies to shift gaze to the labeled referent; from this, we found slower latencies in the autistic group than in the nonspectrum group, in line with previous findings. We then examined features of parents' language and found that parents in both groups produced similar language, suggesting that parents may not adjust their language input according to children's speed of language processing. This finding suggests that (1) capturing parental sensitivity to children's receptive language, and specifically language processing, may enrich our models of individual differences in language input, and (2) future work should investigate if supporting caregivers in tuning their language use according to children's language processing can improve children's language outcomes.

Linguistic context in verb learning: Less is sometimes more.

Linguistic contexts provide useful information about verb meanings by narrowing the space of candidate concepts. Intuitively, the more information, the better. For example, "the tall girl is fezzing," as compared to "the girl is fezzing," provides more information about which event, out of multiple candidate events, is being labeled; thus, we may expect it to better facilitate verb learning. However, we find evidence to the contrary: in a verb learning study, preschoolers (N = 60, mean age = 38 months) only performed above chance when the subject was an unmodified determiner phase, but not when it was modified (Experiment 1). Experiment 2 replicated this pattern with a different set of stimuli and a wider age range (N = 60, mean age = 45 months). Further, in Experiment 2, we looked at both learning outcomes--by evaluating pointing responses at Test, and also the learning process--by tracking eye gaze during Familiarization. The results suggest that children's limited processing abilities are to blame for poor learning outcomes, but that a nuanced understanding of how processing affects learning is required.

Two-year-olds consolidate verb meanings during a nap.

Successful word learning requires establishing an initial representation that is sufficiently robust to be retained in memory. Sleep has profound advantages for memory consolidation, but evidence concerning the effects of sleep in young children's word learning is slim and focuses almost exclusively on learning nouns. Verbs are representationally more complex and are often learned from non-concurrent linguistic and observational information (e.g., hearing "let's pour your milk" before the pouring event takes place). What remains unknown is whether initial representations built this way are robust enough to sustain a delay, and how these representations are affected by sleep. We presented two-year-olds with non-concurrent linguistic and observational information about novel verbs and immediately tested their knowledge of the verbs' meanings by evaluating their eye gaze as they looked at potential referents. Then, after a 4-hour delay during which half of the children napped and half remained awake, we retested them to see if they remembered the verbs' meanings. The results demonstrate differences in two-year-olds' representations of a novel verb before and after the delay; specifically, their verb representations withstood the 4-hour delay if they had napped, but decayed if they had remained awake.

Prosody and Function Words Cue the Acquisition of Word Meanings in 18-Month-Old Infants.

Language acquisition presents a formidable task for infants, for whom word learning is a crucial yet challenging step. Syntax (the rules for combining words into sentences) has been robustly shown to be a cue to word meaning. But how can infants access syntactic information when they are still acquiring the meanings of words? We investigated the contribution of two cues that may help infants break into the syntax and give a boost to their lexical acquisition: phrasal prosody (speech melody) and function words, both of which are accessible early in life and correlate with syntactic structure in the world's languages. We show that 18-month-old infants use prosody and function words to recover sentences' syntactic structure, which in turn constrains the possible meanings of novel words: Participants ( N = 48 in each of two experiments) interpreted a novel word as referring to either an object or an action, given its position within the prosodic-syntactic structure of sentences.

Personal pronoun usage in maternal input to infants at high vs. low risk for autism spectrum disorder.

Children with autism spectrum disorder (ASD) are prone to personal pronoun difficulties. This paper investigates maternal input as a potential contributing factor, focusing on an early developmental stage before ASD diagnosis. Using Quigley and McNally's (2013) corpus of maternal speech to infants (3-19 months; N = 19) who are either at high or low risk for a diagnosis of ASD (Quigley & McNally, 2013), we asked whether mothers used fewer pronouns with high-risk infants. Indeed, high-risk infants heard fewer second-person pronouns relative to their names than low-risk infants. We further investigated the contexts in which mothers were using infants' names. Our results indicated that mothers of high-risk infants often used the infants' names simply to get their attention by calling them. We suggest that high-risk infants may thus hear relatively fewer pronouns because their mothers spend more time trying to get their attention. This may be related to differences in social-communicative behavior between low-risk and high-risk infants.

Word learning mechanisms.

How do children acquire the meanings of words? Many word learning mechanisms have been proposed to guide learners through this challenging task. Despite the availability of rich information in the learner's linguistic and extralinguistic input, the word-learning task is insurmountable without such mechanisms for filtering through and utilizing that information. Different kinds of words, such as nouns denoting object concepts and verbs denoting event concepts, require to some extent different kinds of information and, therefore, access to different kinds of mechanisms. We review some of these mechanisms to examine the relationship between the input that is available to learners and learners' intake of that input-that is, the organized, interpreted, and stored representations they form. We discuss how learners segment individual words from the speech stream and identify their grammatical categories, how they identify the concepts denoted by these words, and how they refine their initial representations of word meanings. WIREs Cogn Sci 2017, 8:e1435. doi: 10.1002/wcs.1435 This article is categorized under: Linguistics > Language Acquisition Psychology > Language.