1,720,965 research outputs found
Typical development of Motion perception and Form discrimination abilities in children
No full textVisual functions have been widely investigated in patients with developmental
disorders. This study aims to analyze the development of dorsal
and ventral visual function in children with typical development, measured
as motion and form discrimination abilities. A sample of 304 children
(age: 4-12 years; 154 males) participated in the experiment. Non-verbal
intelligence (Raven’s matrices), visual acuity (Lea test), motion perception
(motion coherence test-MCT) and form recognition (form coherence
test-FCT) were assessed. The MCT consists of 150 white dots on a black
background moving coherently at a constant velocity in one of the eight
directions (signal) or in a Brownian manner (noise). The task was to recognize
the direction of the signal dots. The FCT consists of white dots (signal)
composing one of eight possible forms through spatial alignment of the
dots, the noise was created by non-aligned dots distorting the form. The
task was to recognize the form. Difficulty was increased by reducing the
dot coherence (signal/noise) from 100% (no noise) to 36% in five levels.
MANOVA showed a significant increment of motion and form perception
accuracy with age, steeper for form as compared to motion recognition.
Both functions are influenced by noise but motion discrimination seemed
to be less affected. While noise had a stronger effect on the younger children
in the FCT (worse performance with noise in the youngest) no such
age effect was found in MCT. Motion and form perception are related
to general intelligence at different ages as well as to the visual acuity.
These results confirm the slowness in development of dorsal function
as compared to ventral function. Visuo-spatial attention, general intelligence
and visual acuity mediate the visual functionality development
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Analisi dell’efficacia di un intervento volto alla promozione dei prerequisiti delle abilità di lettura. Uno studio preliminare su classi prime della scuola primaria
No full textScopo del presente studio è la valutazione dell’efficacia di un programma di intervento di potenziamento delle competenze fonologiche e metafonologiche, in quanto abilità precursori a fondamento dell’apprendimento della lettoscrittura. Lo studio ha coinvolto 99 bambini (f = 55; m= 44) frequentanti cinque classi prime della scuola primaria. Il campione è stato diviso in: gruppo di potenziamento composto da 3 classi e gruppo di controllo composto da 2 classi.
Inoltre i bambini sono stati classificati in «a rischio DSA» e «non a rischio» in base alle valutazioni sulle capacità fonologiche e metafonologiche, percettive e visuo-motorie effettuate prima del trattamento. L’intervento è strutturato in
fasi ed è standard per tutte le classi. Prevede 3 incontri settimanali di 30 minuti ciascuno, per una durata complessiva di 15 settimane. I risultati mostrano che i soggetti sottoposti a potenziamento ottengono un miglioramento maggiore rispetto al gruppo di controllo nelle abilità potenziate. Le competenze nelle quali è stato riscontrato un miglioramento significativo sono quelle di fluenza verbale e di sintesi fonemica. Inoltre è emerso che, nel gruppo di potenziamento,
sia i bambini a rischio DSA che quelli non a rischio ottengono un vantaggio dall'intervento. I risultati del presente studio confermano l’efficacia del programma di intervento effettuato all'interno del contesto classe e basato sul potenziamento delle abilità prerequisito per l’apprendimento delle abilità di lettoscrittura
Relazione tra Inibizione Comportamentale valutata da madri e insegnanti e competenze metafonologiche.
No full textA test for the evaluation of form perception ability: Form Coherence Test
No full textThe aim of this study is the assessment of the applicability of the Form Coherence Test in a population of infants and adolescents. The Form Coherence Test is a computerized test for the evaluation of form perception ability. The subject is asked to discriminate a shape-stimulus among eight possible forms. The form perception is obtained by spatial coherent luminance dots visualized on a black background. Stimuli are presented in five levels of coherence which determines the difficulty of the task: starting from the 100% of coherence level, the number 1 of the coherently aligned dots exponentially decreases while the number of non-coherent dots (noise) increases. A sample of two hundred and fifty children (range 5-12 years) took part in the study. Accuracy is measured as the number of correct answers for each coherence level and for each stimulus. The Generalized Estimating Equation Model shows that the form perception accuracy decreased significantly in the subsequent coherence levels, starting from the 100% to 45%. The number of correct answers raised significantly with age. Age also affects the identification of the eight forms characterized by different difficulty. The results showed that Form Coherence Test is an instrument appropriate for the considered ages and allowed to evaluate the subject’s performance at different coherence level taking into account the age
Motion-from-Form perception in Scotopic and in Photopic light conditions
No full textHuman visual perception is globally worsened under dim light condition.
The aim of this study was to investigate how rod-dominated vision
affects motion perception in a motion-from-form (MFF) and motion coherence
(MC) task. Thirty healthy subjects (11 males, mean age 21.3 years)
participated in the experiment. MFF and MC were tested both in scotopic
and photopic light conditions. Both the MFF and MC stimuli consisted of
nine empty circles moving coherently at a constant velocity of 10.7°/sec
in one of eight directions (cardinal and oblique). Five noise-levels were
used: starting from zero, the noise increased by 6 units in each following
level. In the MFF test 169 empty white squares acted as stationary background.
Nine target-stimuli were drawn in place of the same number
of squares. To make the shape appear to move, in the subsequent frame
each target-stimulus reverted to square while the next square changed
to circle, following a specific direction. The noise consisted of circle positioned
randomly in the space, irrespectively to their previous position. In
the MC test the target-stimuli moved coherently on a black background
and the noise was obtained by stimuli moving in a Brownian manner. The
subjects had to identify the directions of the coherent motion in both tests.
The accuracy was evaluated for each condition. ANOVA showed a significant
global effect of light condition, evidencing disrupted performances
in rod-dominated vision, significant differences between the types of stimuli
(lower scores in MFF as compared to MC) and a significant interaction
stimuli type by light condition. In conclusion, the results confirm that in
scotopic light levels motion perception is not significantly altered using
MC, while it is degraded in higher order motion stimuli, such as MFF
Internalizing Symptoms in Developmental Dyslexia: A Comparison Between Primary and Secondary School
Full text linkAlthough the relationship between developmental dyslexia (DD) and the risk of
occurrence of internalizing symptomatology has been widely investigated in the extant
literature, different findings have been reported. In this study, two experiments with two
general purposes are presented. The first study investigates whether the differences
in the severity of internalizing symptoms between DD and controls are greater in
students attending secondary school than in those attending primary school. Sixtyfive
DD and 169 controls attending primary and secondary school took part in the
first study. The diagnosis of dyslexia was obtained from standardized reading tests;
internalizing symptom severity was assessed with the Self Administrated Psychiatric
Scales for Children and Adolescents questionnaire. The results showed that adolescents
with dyslexia had an increased level of self-perceived anxiety, depression and somatic
symptoms, whereas no significant differences between DD and controls emerged
in childhood. In the second study, a cohort of adolescents attending secondary
school (DD = 44; controls = 51) was closely analyzed to clarify whether contextual
and subjective factors could contribute toward exacerbating the risk of internalizing
symptomatology at that age. Internalizing symptom severity was assessed with the
Child Behavior Checklist, Youth Self Report questionnaire, decision-making factors
were measured with the Melbourne Decision Making Questionnaire, and student’s
quality of life was gaged using the Clipper test. The results showed that high levels
of internalizing symptoms in DD were associated with a low level of self-esteem and the
tendency to react to problematic situations with hyperactivation. By contrast, positive
relationships with peers were associated with low symptom severity. In conclusion, the
intensified internalizing symptoms that could emerge in adolescents in association with
the presence of dyslexia are predicted by social protective and risk factors that are
associated with symptom severity. Accordingly, the results suggest that remediation
programs for dyslexia should include implementing motivation strategies, self-esteem
enhancement activities and building peers networks that, starting in childhood, can
prevent the appearance of internalizing symptoms
Two-step Cluster Analysis Application to a Sample of Psychiatric Inpatients at Psychiatric Service of Diagnosis and Care
No full text- …
