C. Loureiro

Speech rate and fluency in children and adolescents.

Reduced speech fluency is frequent in clinical paediatric populations, an unexplained finding. To investigate age related effects on speech fluency variables, we analysed samples of narrative speech (picture description) of 308 healthy children, aged 5 to 17 years, and studied its relation with verbal fluency tasks. All studied measures showed significant developmental effects. Speech rate and verbal fluency scores increased, while pauses, repetitions and locution time declined with age. Speech rate correlated with semantic fluency tasks suggesting that it also depends upon the efficacy of lexical retrieval. These results indicate that the interpretation of disorders of speech fluency in childhood must incorporate age appropriate norms.

Effect of lesion site on serial position during list learning: a study with the CVLT.

Successful learning of supraspan word lists such as the California Verbal Learning Test (CVLT) relies more on clustering strategies than rote learning, subserved by the frontal and temporal lobes. The authors studied the effect of word sequence in CVLT learning, in 15 patients with frontal (FLL) and 15 temporal (TLL) lesions, and 33 controls. Experimental measures were: number of clusters, number of first (FI), middle (MI) and last items (LI), in learning trials and in total immediate recall. FLL disclosed significantly lower FI along learning. Clusters were similar among groups. This difficulty is discussed according to the role of frontal lobes in learning and memory.

Importance of N2-Fixation on the Productivity at the North-Western Azores Current/Front System, and the Abundance of Diazotrophic Unicellular Cyanobacteria

To understand the impact of the northwestern Azores Current Front (NW-AzC/AzF) system on HCO3−-and N2-fixation activities and unicellular diazotrophic cyanobacteria (UCYN) distribution, we combined geochemical and biological approaches from the oligotrophic surface to upper mesopelagic waters. N2-fixation was observed to sustain 45–85% of the HCO3−-fixation in the picoplanktonic fraction performing 47% of the total C-fixation at the deep chlorophyll maximum north and south of the AzF. N2-fixation rates as high as 10.9 μmol N m-3 d-1 and surface nitrate δ15N as low as 2.7‰ were found in the warm (18–24°C), most saline (36.5–37.0) and least productive waters south of the AzF, where UCYN were the least abundant. However, picoplanktonic UCYN abundances up to 55 cells mL-1 were found at 45–200m depths in the coolest nutrient-rich waters north of the AzF. In this area, N2-fixation rates up to 4.5 μmol N m-3 d-1 were detected, associated with depth-integrated H13CO3−-fixation rates at least 50% higher than observed south of the AzF. The numerous eddies generated at the NW-AzC/AzF seem to enhance exchanges of plankton between water masses, as well as vertical and horizontal diapycnal diffusion of nutrients, whose increase probably enhances the growth of diazotrophs and the productivity of C-fixers.

Factors affecting the retrieval of famous names

Tests of famous faces are used to study language and memory. Yet, the effect of stimulus properties on performance has not been fully investigated. To identify factors influencing proper name retrieval and to probe stimulus-specific parameters within proper name lexicon, we analysed the results obtained by 300 healthy participants on a test of famous faces that includes 74 personalities. A factor analysis yielded five main factors that were characterized by language (national or foreign names), epoch of peak popularity (current, recent or past) and occupation (politicians, entertainment and sports) of the personalities. Multiple regression analysis showed that participants’ education, age and gender accounted for 10–32% of the variance in factor scores. These results indicate that there are variables of the stimulus and participants’ that must be taken into account in proper name testing and in designing tests aimed to differentiate age-associated difficulties from cognitive decline.

Grammatical dissociation during acquired childhood aphasia

Aim  We report the case of a 6‐year‐old female who suffered a left hemisphere stroke attributed to a genetically determined prothrombotic state. She presented a fluent speech pattern with selective difficulty in retrieving names but not verbs. An evaluation was designed to clarify whether her symptoms represented a specific impairment of name retrieval.