Perception of Filtered Speech by Children with Developmental Dyslexia and Children with Specific Language Impairments

Here we use two filtered speech tasks to investigate children’s processing of slow (<4 Hz) versus faster (∼33 Hz) temporal modulations in speech. We compare groups of children with either developmental dyslexia (Experiment 1) or speech and language impairments (SLIs, Experiment 2) to groups of typically-developing (TD) children age-matched to each disorder group. Ten nursery rhymes were filtered so that their modulation frequencies were either low-pass filtered (<4 Hz) or band-pass filtered (22 – 40 Hz). Recognition of the filtered nursery rhymes was tested in a picture recognition multiple choice paradigm. Children with dyslexia aged 10 years showed equivalent recognition overall to TD controls for both the low-pass and band-pass filtered stimuli, but showed significantly impaired acoustic learning during the experiment from low-pass filtered targets. Children with oral SLIs aged 9 years showed significantly poorer recognition of band pass filtered targets compared to their TD controls, and showed comparable acoustic learning effects to TD children during the experiment. The SLI samples were also divided into children with and without phonological difficulties. The children with both SLI and phonological difficulties were impaired in recognizing both kinds of filtered speech. These data are suggestive of impaired temporal sampling of the speech signal at different modulation rates by children with different kinds of developmental language disorder. Both SLI and dyslexic samples showed impaired discrimination of amplitude rise times. Implications of these findings for a temporal sampling framework for understanding developmental language disorders are discussed.

Progression of left atrial volume index in a population at risk for heart failure:a substudy of the STOP-HF (St Vincent's Screening TO Prevent Heart Failure) trial

AIMS: Limited data are available concerning the evolution of the left atrial volume index (LAVI) in pre-heart failure (HF) patients. The aim of this study was to investigate clinical characteristics and serological biomarkers in a cohort with risk factors for HF and evidence of serial atrial dilatation.

METHODS AND RESULTS: This was a prospective substudy within the framework of the STOP-HF cohort (NCT00921960) involving 518 patients with risk factors for HF electively undergoing serial clinical, echocardiographic, and natriuretic peptide assessment. Mean follow-up time between assessments was 15 ± 6 months. 'Progressors' (n = 39) were defined as those with serial LAVI change ≥3.5 mL/m(2) (and baseline LAVI between 20 and 34 mL/m(2)). This cut-off was derived from a calculated reference change value above the biological, analytical, and observer variability of serial LAVI measurement. Multivariate analysis identified significant baseline clinical associates of LAVI progression as increased age, beta-blocker usage, and left ventricular mass index (all P < 0.05). Serological biomarkers were measured in a randomly selected subcohort of 30 'Progressors' matched to 30 'Non-progressors'. For 'Progressors', relative changes in matrix metalloproteinase 9 (MMP9), tissue inhibitor of metalloproteinase 1 (TIMP1), and the TIMP1/MMP9 ratio, markers of interstitial remodelling, tracked with changes in LAVI over time (all P < 0.05).

CONCLUSION: Accelerated LAVI increase was found to occur in up to 14% of all pre-HF patients undergoing serial echocardiograms over a relatively short follow-up period. In a randomly selected subcohort of 'Progressors', changes in LAVI were closely linked with alterations in MMP9, TIMP1, and the ratio of these enzymes, a potential aid in highlighting this at-risk group.