Auditory verb recognition in developmental language impairment

This research addresses the issues of frequency and regularity in auditory verb recognition and their importance for the organization of the mental lexicon in DLI francophones. A primed auditory lexical decision task probes reaction times and response accuracy in DLI and control participants on frequent and infrequent, and regular and irregular, inflected forms of verbs. Results show no priming for inflectionally related forms as well as strong frequency effects in DLI participants. These findings lend additional support to the hypothesis that developmental language impairment is a deficit in lexical representation.     

The cues that children use in acquiring adjectival phrases and compound nouns: evidence from bilingual children

This study explores the cues used in acquisition of two semantically similar structures that are ordered differently in French and English: adjectival phrases and compound nouns. One possible prediction is that children attend primarily to meaning, so they should order both structures similarly. Another is that children attend primarily to structure, so they should learn these structures independently. Two kinds of data were obtained from eight 4-year old bilinguals: (1) spontaneous production and (2) experimental elicitation. The children were nearly perfect in their ordering of adjectival phrases, but less so in compounds. These results conform to neither prediction, leaving open the question of which cues children use in acquisition.     

Crossmodal temporal order and processing acuity in developmentally dyslexic young adults

We investigated crossmodal temporal performance in processing rapid sequential nonlinguistic events in developmentally dyslexic young adults (ages 20-36 years) and an age- and IQ-matched control group in audiotactile, visuotactile, and audiovisual combinations. Two methods were used for estimating 84% correct temporal acuity thresholds: temporal order judgment (TOJ) and temporal processing acuity (TPA). TPA requires phase difference detection: the judgment of simultaneity/nonsimultaneity of brief stimuli in two parallel, spatially separate triplets. The dyslexic readers' average temporal performance was somewhat poorer in all six comparisons; in audiovisual comparisons the group differences were not statistically significant, however. A principal component analysis indicated that temporal acuity and phonological awareness are related in dyslexic readers. The impairment of temporal input processing seems to be a general correlative feature of dyslexia in children and adults, but the overlap in performance between dyslexic and normal readers suggests that it is not a sufficient reason for developmental reading difficulties.     

Effects of right and left hemisphere damage on performance of the "Right Hemisphere Communication Battery"

A Hebrew adaptation of Gardner and Brownell's (1986) "Right Hemisphere Communication Battery" (HRHCB) was administered to 27 right brain-damaged (RBD) patients, 31 left brain-damaged (LBD) patients, and 21 age-matched normal controls. Both patient groups showed deficits relative to controls and overall there was no difference between the two patient groups. A factor analysis of patients' scores on the HRHCB yielded two interpretable factors, a verbal and a nonverbal one. These factors were not lateralized. Performance of patients on the HRHCB correlated significantly and positively with performance on most tests of basic language functions, measured with a Hebrew adaptation of the "Western Aphasia Battery" (HWAB) and with other cognitive functions measured with standardized neuropsychological tests. There were stronger correlations of HRHCB with subtests of the HWAB in LBD patients and with nonlanguage cognitive tests in RBD patients. In the LBD group, HRHCB subtests' scores correlated negatively with lesion extent in frontal and temporal perisylvian regions. Such localization was not observed in RBD patients. The results argue against selective right hemisphere (RH) involvement in the RHCB, alleged to measure pragmatic aspects of language use, and show, instead, bilateral involvement. The results also argue against a modular organization of these functions of language use, especially in the RH.     

Is phonological information mapped onto semantic information in a one-to-one manner?

Spoken word recognition models have to explain the influence of mismatching information on lexical activation. The effect of mismatching information is usually addressed with cross-modal semantic priming experiments using priming effects as a measure of the degree of lexical activation. Pseudowords phonologically related to a semantic associate of the target, e.g., *domato-PAPRIKA, serve as primes. Mismatch effects at the word form level are supposed to percolate unaltered to the semantic level. We show that cross-modal semantic priming might underestimate activation at the word form level. Targets (e.g., PAPRIKA) were preceded by either phonologically related pseudoword primes (e.g., *baprika) or semantically related pseudoword primes (e.g., *domato). Different priming and RT patterns were obtained for the two priming relations.     

Relative damping improves linear mass-spring models of goal-directed movements

A limitation of a simple linear mass-spring model in describing goal directed movements is that it generates rather slow movements when the parameters are kept within a realistic range. Does this imply that the control of fast movements cannot be approximated by a linear system? In servo-control theory, it has been proposed that an optimal controller should control movement velocity in addition to position. Instead of explicitly controlling the velocity, we propose to modify a simple linear mass-spring model. We replaced the damping relative to the environment (absolute damping) with damping with respect to the velocity of the equilibrium point (relative damping). This gives the limb a tendency to move as fast as the equilibrium point. We show that such extremely simple models can generate rapid single-joint movements. The resulting maximal movement velocities were almost equal to those of the equilibrium point, which provides a simple mechanism for the control of movement speed. We further show that peculiar experimental results, such as an 'N-shaped' equilibrium trajectory and the difficulties to measure damping in dynamic conditions, may result from fitting a model with absolute damping where one with relative damping would be more appropriate. Finally, we show that the model with relative damping can be used to model subtle differences between multi-joint interceptions. The model with relative damping fits the data much better than a version of the model with absolute damping.     

"Clockness" in the detection of dementia: a semantic-conceptual effect

We studied aspects of clock cognition that might underlie the sensitivity of the CDT in screening for dementia of the Alzheimer type (DAT). Two groups, 15 patients with mild-moderate DAT and 15 controls, were assessed with the CDT and specially designed tests of clock-related cognition. Patients were impaired on the CDT, but they did not differ from controls in copying a clock face or selecting the correct representation of a given time. Patients were worse than controls at distinguishing between clock and nonclock objects, detecting anomalies in clocks, and in setting time irrespective of response format. These findings suggest that semantic-conceptual aspects of clock-related cognition are important in discriminating between patients with DAT and controls.     

The discrimination of cat odours by humans

We explored the ability of humans to identify individual cats by smell. Twenty-five cat owners were required to indicate which of two odours (one belonging to their own cat and one belonging to an unfamiliar cat) smelt the strongest, most pleasant, and which belonged to their own cat. Only thirteen (52%) of the participants were able to recognise the odour of their own cat.     

Differential functioning of the Beck depression inventory in late-life patients: use of item response theory

The present analyses examined age-related measurement bias in responses to items on the revised Beck Depression Inventory (BDI) in depressed late-life patients versus midlife patients. Item response theory (IRT) models were used to equate the scale and to differentiate true-group differences from bias in measurement in the 2 samples. Baseline BDI data (218 late life and 613 midlife) were used for the present analysis. IRT results indicated that late-life patients tended to report fewer cognitive symptoms, especially at low to average levels of depression. Conversely, they tended to report more somatic symptoms, especially at higher levels of depression. Adjusted cutoff scores in the late-life group are provided, and possible reasons for age-related differences in the performance of the BDI are discussed.