The relationship between motor control and phonology in dyslexic children

Background: The goal of this study was to investigate the automaticity/cerebellar theory of dyslexia. We tested phonological skills and cerebellar function in a group of dyslexic 8-12 year old children and their matched controls. Tests administered included the Phonological Assessment Battery, postural stability, bead threading, finger to thumb and time estimation. Results: Dyslexic children were found to be significantly poorer than the controls at all tasks but time estimation. About 75% of dyslexics were more than one standard deviation below controls in phonological ability, and 50% were similarly impaired in motor skills. However, at least part of the discrepancy in motor skills was due to dyslexic individuals who had additional disorders (ADHD and/or DCD). The absence of evidence for a time estimation deficit also casts doubt on the cerebellar origin of the motor deficiency. About half the dyslexic children didn't have any motor problem, and there was no evidence for a causal relationship between motor skills on the one hand and phonological and reading skills on the other. Conclusion: This study provides partial support for the presence of motor problems in dyslexic children, but does not support the hypothesis that a cerebellar dysfunction is the cause of their phonological and reading impairment

The mystery of the brain-culture interface

Nature and culture work together to shape who we are. We are embedded in culture and are profoundly influenced by what those around us say and do. The interface between minds occurs at the level of explicit metacognition, which is at the top of our brain's control hierarchy. But how do our brains do this

Egocentrism, allocentrism, and Asperger syndrome

In this paper, we attempt to make a distinction between egocentrism and allocentrism in social cognition, based on the distinction that is made in visuo-spatial perception. We propose that it makes a difference to mentalizing whether the other person can be understood using an egocentric (‘‘you'') or an allocentric (‘‘he/ she/they'') stance. Within an egocentric stance, the other person is represented in relation to the self. By contrast, within an allocentric stance, the existence or mental state of the other person needs to be represented as independent from the self. We suggest here that people with Asperger syndrome suffer from a disconnection between a strong naı¨ve egocentric stance and a highly abstract allocentric stance. We argue that the currently used distinction between first-person and third-person perspective-taking is orthogonal to the distinction between an egocentric and an allocentric stance and therefore cannot serve as a critical test of allocentrism

Reading music modifies spatial mapping in pianists

We used a novel musical Stroop task to demonstrate that musical notation is automatically processed in trained pianists. Numbers were superimposed onto musical notes, and participants played five-note sequences by mapping from numbers to fingers instead of from notes to fingers. Pianists’ reaction times were significantly affected by the congruence of the note/number pairing. Nonmusicians were unaffected. In a nonmusical analogue of the task, pianists and nonmusicians showed a qualitative difference on performance of a vertical-to-horizontal stimulus–response mapping task. Pianists were faster when stimuli specifying a leftward response were presented in vertically lower locations and stimuli specifying a rightward response were presented in vertically higher locations. Nonmusicians showed the reverse pattern. No group differences were found on a task that required horizontal-to-horizontal mappings. We suggest that, as a result of learning to read and play keyboard music, pianists acquire vertical-to-horizontal visuomotor mappings that generalize outside the musical context

Brief Report: Cognitive Processing of Own Emotions in Individuals with Autistic Spectrum Disorder and in Their Relatives

Difficulties in the cognitive processing of emotions—including difficulties identifying and describing feelings—are assumed to be an integral part of autism. We studied such difficulties via self-report in 27 high-functioning adults with autistic spectrum disorders, their biological relatives (n = 49), and normal adult controls (n = 35), using the 20-item Toronto Alexithymia Scale and the Beck Depression Inventory. The individuals with autism spectrum disorders were significantly more impaired in their emotion processing and were more depressed than those in the control and relative groups

TMS produces two dissociable types of speech disruption

We aimed to use repetitive transcranial magnetic stimulation (rTMS) to disrupt speech with the specific objective of dissociating speech disruption according to whether or not it was associated with activation of the mentalis muscle. Repetitive transcranial magnetic stimulation (rTMS) was applied over two sites of the right and left hemisphere while divisions counted aloud and recited the days of the week, months of the year, and nursery rhymes. Analysis of EMG data and videotaped recordings showed that rTMS applied over a posterior site, lateral to the motor hand area of both the right and the left hemisphere resulted in speech disruption that was accompanied by activation of the mentalis muscle, while rTMS applied over an anterior site on the left but not the right hemisphere resulted in speech disruption that was dissociated from activation of the mentalis muscle. The findings provide a basis for the use of subthreshold stimulation over the extrarolandic speech disruption site in order to probe the functional properties of this area and to test psychological theories of linguistic function

Left posterior BA37 is involved in object recognition: a TMS study

Functional imaging studies have proposed a role for left BA37 in phonological retrieval, semantic processing, face processing and object recognition. The present study targeted the posterior aspect of BA37 to see whether a deficit, specific to one of the above types of processing could be induced. Four conditions were investigated: word and nonword reading, colour naming and picture naming. Repetitive transcranial magnetic stimulation (rTMS) was delivered over posterior BA37 of the left and right hemispheres (lBA37 and rBA37, respectively) and over the vertex. divisions were significantly slower to name pictures when TMS was given over lBA37 compared to vertex or rBA37. rTMS over lBA37 had no significant effect on word reading, nonword reading or colour naming. The picture naming deficit is suggested to result from a disruption to object recognition processes. This study corroborates the finding from a recent imaging study, that the most posterior part of left hemispheric BA37 has a necessary role in object recognition

Theories of developmental dyslexia: Insights from a multiple case study of dyslexic adults

A multiple case study was conducted in order to assess three leading theories of developmental dyslexia: the phonological, the magnocellular (auditory and visual) and the cerebellar theories. Sixteen dyslexic and 16 control university students were administered a full battery of psychometric, phonological, auditory, visual and cerebellar tests. Individual data reveal that all 16 dyslexics suffer from a phonological deficit, 10 from an auditory deficit, 4 from a motor deficit, and 2 from a visual magnocellular deficit. Results suggest that a phonological deficit can appear in the absence of any other sensory or motor disorder, and is sufficient to cause a literacy impairment, as demonstrated by 5 of the dyslexics. Auditory disorders, when present, aggravate the phonological deficit, hence the literacy impairment. However, auditory deficits cannot be characterised simply as rapid auditory processing problems, as would be predicted by the magnocellular theory. Nor are they restricted to speech. Contrary to the cerebellar theory, we find little support for the notion that motor impairments, when found, have a cerebellar origin, or reflect an automaticity deficit. Overall, the present data support the phonological theory of dyslexia, while acknowledging the presence of additional sensory and motor disorders in certain individuals