Children learn words easier when they are interested in the category to which the word belongs

The overall pattern of vocabulary development is relatively similar across children learning different languages. However, there are considerable differences in the words known to individual children. Historically, this variability has been explained in terms of differences in the input. Here, we examine the alternate possibility that children's individual interest in specific natural categories shapes the words they are likely to learn – a child who is more interested in animals will learn a new animal name easier relative to a new vehicle name. Two‐year‐old German‐learning children (N = 39) were exposed to four novel word–object associations for objects from four different categories. Prior to the word learning task, we measured their interest in the categories that the objects belonged to. Our measure was pupillary change following exposure to familiar objects from these four categories, with increased pupillary change interpreted as increased interest in that category. Children showed more robust learning of word–object associations from categories they were more interested in relative to categories they were less interested in. We further found that interest in the novel objects themselves influenced learning, with distinct influences of both category interest and object interest on learning. These results suggest that children's interest in different natural categories shapes their word learning. This provides evidence for the strikingly intuitive possibility that a child who is more interested in animals will learn novel animal names easier than a child who is more interested in vehicles.     

Speech perception deficits in Parkinson's disease: underestimation of time intervals compromises identification of durational phonetic contrasts

Besides motor, vegetative, and cognitive signs, patients suffering from Parkinson's disease (PD) may show distinct perceptual deficits such as underestimation of time intervals extending across several seconds. Assuming this impairment also to affect the domain of tens of milliseconds, disrupted encoding of the acoustic speech signal with respect to segment durations conveying linguistic information must be expected. To test this hypothesis, 10 PD patients and matched controls performed an identification task using a series of 10 stimuli derived from the utterance "Boten" (/bo:tn/, 'messengers'; produced with nasal plosion) by exclusive manipulation of occlusion length (110-20 ms in steps of 10 ms). Under these conditions, word-medial silence cues the voicing category of the respective stop consonant. Seven PD subjects showed normal identification curves, i.e., categorized the shortest and longest stimuli with high probability each as the minimal pair cognates "Boden" and "Boten," respectively. In contrast, the remaining three patients labeled all items across the complete range of occlusion lengths as "Boden." A subsequent experiment found a horizontal shift of the identification curves toward larger signal durations (> 120 ms) in these three subjects. Bilateral cerebellar degeneration has been found to yield a different response pattern, i.e., near-chance level of performance. Considering recent information-processing models of scalar interval timing, striatal disorders seem to slow down an oscillatory pacemaker, whereas cerebellar dysfunctions may impair comparison of measured durations with stored reference memory traces.     

Is there an optimal factor structure of the Positive and Negative Syndrome Scale in patients with first‐episode psychosis?

The Positive and Negative Syndrome Scale (PANSS) is the most widely used scale to assess a variety of symptoms in patients with schizophrenia and other psychoses. The factor structure of the PANSS has been examined with confirmatory factor analyses in several studies, but not in a well‐defined first‐episode psychosis sample. The aim of this paper is to examine the statistical fit of five different PANSS models in a first‐episode, non‐affective psychosis sample. Confirmatory factor analyses were performed on PANSS data (n = 588). A main criterion for best fit was defined as the Expected Cross Validation Index (ECVI). No tested model revealed an optimally satisfactory model fit index. The Wallwork/Fortgang five‐factor model demonstrated the most optimal psychometric properties. The corresponding subscales of all evaluated five‐factor models were strongly intercorrelated. The Wallwork/Fortgang five‐factor model was found to be statistically and clinically ideal among patients with first‐episode psychosis. Therefore, we recommend this model in forthcoming studies among patients with first‐episode psychosis. However, to prevent the loss of clinically valuable information on an item level, we do not recommend removing any items from the original form. Our study also implies that the specific choice of model will not have a substantial effect on outcome results in studies on the course and outcome in first‐episode psychosis.     

Gender differences on the Five to Fifteen questionnaire in a non‐referred sample with inattention and hyperactivity‐impulsivity and a clinic‐referred sample with hyperkinetic disorder

Lambek, R., Trillingsgaard, A., Kadesjö, B., Damm, D. & Thomsen, P. H. (2010). Gender differences on the Five to Fifteen questionnaire in a non‐referred sample with inattention and hyperactivity‐impulsivity and a clinic‐referred sample with hyperkinetic disorder. Scandinavian Journal of Psychology 51, 540–447. The aim of the present study was to examine gender differences in children with inattention, hyperactivity, and impulsivity on the Five to Fifteen (FTF) parent questionnaire. First, non‐referred girls (n = 43) and boys (n = 51) with problems of attention and hyperactivity‐impulsivity and then clinic‐referred girls (n = 35) and boys (n = 66) with hyperkinetic disorder (HKD) were compared on the FTF. Results suggested that non‐referred boys were more hyperactive‐impulsive than non‐referred girls, whereas clinic‐referred boys and girl with HKD were more similar than dissimilar on the FTF questionnaire. Secondly, it was examined whether the application of gender mixed norms versus gender specific norms would result in varying proportions of clinic‐referred children with HKD being identified as impaired on the subdomains of the FTF questionnaire. Based on results it was concluded that the use of a gender mixed normative sample may lead to overestimation of impairment in boys with HKD, but the type of sample applied to define impairment on the FTF should depend on the purpose for applying the questionnaire.     

Effect of low dose ionizing radiation exposure in utero on cognitive function in adolescence

Heiervang, K. S., Mednick, S., Sundet, K. & Rund, B. R. (2010). Effect of low dose ionizing radiation exposure in utero on cognitive function in adolescence. Scandinavian Journal of Psychology, 51, 210–215. Radiation from the Chernobyl nuclear power plant meltdown greatly affected several Norwegian counties. The cognitive consequences of in utero exposure to radiation from the Chernobyl accident have been intensely debated. This study examines the cognitive outcomes for those Norwegians who were exposed as fetuses to the fallout from Chernobyl. The participants, 84 adolescents who were exposed in utero to radiation from the most contaminated areas in Norway and 94 adolescents from areas not contaminated by the radiation, were tested on verbal and nonverbal IQ. Two data analyses were conducted. First, using a control‐group design, the IQ scores of exposed and unexposed adolescents were compared. Second, in a timing‐of‐exposure design, those exposed during the most sensitive period were contrasted with those exposed later in gestation. Adolescents exposed to low‐dose ionizing radiation in utero scored significantly lower in full‐scale IQ than unexposed adolescents. The difference was restricted to verbal IQ and was not evident for nonverbal IQ. The effect was not observed in exposed adolescents who had passed the most sensitive gestational period prior to the accident and thus were exposed to the radiation from Chernobyl exclusively after gestational week 16. These participants performed as well as the controls. Although the results should be interpreted cautiously due to the study’s nonrandomized design, the data add new and important support to the hypothesis that the Chernobyl accident may have had a subtle effect on the cognitive functioning of those exposed to low‐dose ionizing radiation in utero during the most sensitive gestational period.     

Temporal processing capabilities in repetition conduction aphasia

This study investigates the temporal resolution capacities of the central-auditory system in a subject (NP) suffering from repetition conduction aphasia. More specifically, the patient was asked to detect brief gaps between two stretches of broadband noise (gap detection task) and to evaluate the duration of two biphasic (WN-3) continuous noise elements, starting with white noise (WN) followed by 3 kHz bandpass-filtered noise (duration discrimination task). During the gap detection task, the two portions of each stimulus were either identical (“intra-channel condition”) or differed (“inter-channel condition”) in the spectral characteristics of the leading and trailing acoustic segments. NP did not exhibit any deficits in the intra-channel condition of the gap detection task, indicating intact auditory temporal resolution across intervals of 1–3 ms. By contrast, the inter-channel condition yielded increased threshold values. Based upon the “multiple-looks” model of central-auditory processing, this profile points at a defective integration window operating across a few tens of milliseconds – a temporal range associated with critical features of the acoustic speech signal such as voice onset time and formant transitions. Additionally, NP was found impaired during a duration discrimination task addressing longer integration windows (ca. 150 ms). Concerning speech, this latter time domain approximately corresponds to the duration of stationary segmental units such as fricatives and long vowels. On the basis of our results we suggest, that the patient’s auditory timing deficits in non-speech tasks may account, at least partially, for his impairments in speech processing.     

The influence of syllable onset complexity and syllable frequency on speech motor control

Functional imaging studies have delineated a "minimal network for overt speech production", encompassing mesiofrontal structures (supplementary motor area, anterior cingulate gyrus), bilateral pre- and postcentral convolutions, extending rostrally into posterior parts of the inferior frontal gyrus (IFG) of the language-dominant hemisphere, left anterior insula as well as bilateral components of the basal ganglia, the cerebellum, and the thalamus. In order to further elucidate the specific contribution of these cerebral regions to speech motor planning, subjects were asked to read aloud visually presented bisyllabic pseudowords during functional magnetic resonance imaging (fMRI). The test stimuli systematically varied in onset complexity (CCV versus CV) and frequency of occurrence (high-frequency, HF versus low-frequency, LF) of the initial syllable. A cognitive subtraction approach revealed a significant main effect of syllable onset complexity (CCV versus CV) at the level of left posterior IFG, left anterior insula, and both cerebellar hemispheres. Conceivably, these areas closely cooperate in the sequencing of subsyllabic aspects of the sound structure of verbal utterances. A significant main effect of syllable frequency (LF versus HF), by contrast, did not emerge. However, calculation of the time series of hemodynamic activation within the various cerebral structures engaged in speech motor control revealed this factor to enhance functional connectivity between Broca's area and ipsilateral anterior insula.     

Voice Onset Time in Ataxic Dysarthria

In eight patients with a purely ataxic syndrome due to cerebellar atrophy the voice onset time (VOT) of word-initial stop consonants was measured at the acoustic signal. The subjects had been asked to produce sentence utterances including either one of the German minimal pair cognates “Daten” (/datn/, “data”) and “Taten” (/tatn/, “deeds”). In addition, a master tape comprising the target words from patients and controls in randomized order was played to six listeners for perceptual evaluation. Two major findings emerged. First, the cerebellar subjects presented with a reduced categorical distinction of the VOT of voiced and unvoiced stop consonants. Second, the patients' target words with initial unvoiced plosive gave rise to a significantly increased number of misassignments at perceptual evaluation. To some extent comparable VOT disruptions have been noted in apraxia of speech and basal ganglia disorders. Thus, different pathomechanisms might result in similar VOT abnormalities.     

Tracking the speech signal – Time-locked MEG signals during perception of ultra-fast and moderately fast speech in blind and in sighted listeners

Blind people can learn to understand speech at ultra-high syllable rates (ca. 20 syllables/s), a capability associated with hemodynamic activation of the central-visual system. To further elucidate the neural mechanisms underlying this skill, magnetoencephalographic (MEG) measurements during listening to sentence utterances were cross-correlated with time courses derived from the speech signal (envelope, syllable onsets and pitch periodicity) to capture phase-locked MEG components (14 blind, 12 sighted subjects; speech rate = 8 or 16 syllables/s, pre-defined source regions: auditory and visual cortex, inferior frontal gyrus). Blind individuals showed stronger phase locking in auditory cortex than sighted controls, and right-hemisphere visual cortex activity correlated with syllable onsets in case of ultra-fast speech. Furthermore, inferior-frontal MEG components time-locked to pitch periodicity displayed opposite lateralization effects in sighted (towards right hemisphere) and blind subjects (left). Thus, ultra-fast speech comprehension in blind individuals appears associated with changes in early signal-related processing mechanisms both within and outside the central-auditory terrain.