Post graphemic impairments of writing: the case of micrographia

Paranormal believers show reduced resting EEG beta band oscillations and inhibitory control than skeptics

Paranormal believers' thinking is frequently biased by intuitive beliefs. Lack of inhibition of these tempting beliefs is considered a key element in paranormal believers' thinking. However, the brain activity related to inhibitory control in paranormal believers is poorly understood. We examined EEG activities at resting state in alpha, beta, and gamma bands with inhibitory control in paranormal believers and skeptics. The present study shows that paranormal belief is related to the reduced power of the alpha, beta, and gamma frequency bands, and reduced inhibitory control. This study may contribute to understanding the differences between believers and skeptics in brain activity related to inhibitory control in paranormal believers.

Progressive macrographia for block letter writing: A case study

"Macrographia", a relatively rare symptom generally following cerebellar diseases, consists of an abnormally large handwriting. The case reported in the present investigation shows several outstanding features. First, it is of the progressive variety, letters increase in size as one goes through the word towards the lower-right portion of space. Moreover, it is limited to one allographic variety, that is, block letters. This phenomenon is previously unreported, all allographic varieties being usually equally affected. Finally, no prominent cerebellar or basal ganglia abnormality could be demonstrated with structural MRI or PET. From a cognitive point of view, a peculiar combination of spatial attention, executive function and working memory deficits is proposed to account for the progressive misalignment and elongation of individual letters when specifically writing in block prints. From an anatomical perspective, the pattern of multifocal lesions, encompassing multiple cortical areas in both hemispheres and the corpus callosum, may support this multi-componential interpretation of the reported phenomenon.

Permanent isolated micrographia from traumatic basal ganglia injury

Micrographia is a rare neurological finding in isolation. Most cases of isolated micrographia have been found in association with focal ischemia of the left basal ganglia. Here, we present a case of post-traumatic micrographia stemming from contusion to the left basal ganglia.

Micrographia, much beyond the writer's hand

INTRODUCTION

This review on micrographia aims to draw the clinician's attention to non-Parkinsonian etiologies, provide clues to differential diagnosis, and summarize current knowledge on the phenomenology, etiology, and mechanisms underlying micrographia.

METHODS

A systematic review of the existing literature was performed.

RESULTS

Micrographia, namely small sized handwriting has long been attributed to Parkinson's disease. However, it has often been observed as part of the clinical picture of additional neurodegenerative disorders, sometimes antedating the motor signs, or following focal basal ganglia lesions without any accompanying parkinsonism, suggesting that bradykinesia and rigidity are not sine-qua-non for the development of this phenomenon. Therefore, micrographia in a patient with no signs of parkinsonism may prompt the clinician to perform imaging in order to exclude a focal basal ganglia lesion. Dopaminergic etiology in this and other cases is doubtful, since levodopa ameliorates letter stroke size only partially, and only in some patients. Parkinsonian handwriting is often characterized by lack of fluency, slowness, and less frequently by micrographia. Deviations from kinematic laws of motion that govern normal movement, including the lack of movement smoothness and inability to scale movement amplitude to the desired size, may reflect impairments in motion planning, possible loss of automaticity and reduced movement vigor.

CONCLUSIONS

The etiology, neuroanatomy, mechanisms and models of micrographia are discussed. Dysfunction of the basal ganglia circuitry induced by neurodegeneration or disruption by focal damage give rise to micrographia.

Examining the central and peripheral processes of written word production through meta-analysis

Producing written words requires “central” cognitive processes (such as orthographic long-term and working memory) as well as more peripheral processes responsible for generating the motor actions needed for producing written words in a variety of formats (handwriting, typing, etc.). In recent years, various functional neuroimaging studies have examined the neural substrates underlying the central and peripheral processes of written word production. This study provides the first quantitative meta-analysis of these studies by applying activation likelihood estimation (ALE) methods (Turkeltaub et al., 2002). For alphabet languages, we identified 11 studies (with a total of 17 experimental contrasts) that had been designed to isolate central and/or peripheral processes of word spelling (total number of participants = 146). Three ALE meta-analyses were carried out. One involved the complete set of 17 contrasts; two others were applied to subsets of contrasts to distinguish the neural substrates of central from peripheral processes. These analyses identified a network of brain regions reliably associated with the central and peripheral processes of word spelling. Among the many significant results, is the finding that the regions with the greatest correspondence across studies were in the left inferior temporal/fusiform gyri and left inferior frontal gyrus. Furthermore, although the angular gyrus (AG) has traditionally been identified as a key site within the written word production network, none of the meta-analyses found it to be a consistent site of activation, identifying instead a region just superior/medial to the left AG in the left posterior intraparietal sulcus. These meta-analyses and the discussion of results provide a valuable foundation upon which future studies that examine the neural basis of written word production can build.

Psychophysics reveals a right hemispheric contribution to body image distortions in women but not men

We tested the hypothesis that the right cerebral hemisphere contributes to the enhanced body image distortions seen in women when compared to men. Using classical psychophysics, 60 right-handed healthy participants (30 women) were briefly presented with size-distorted pictures of themselves, another person (an experimenter), and a non-corporal, familiar object (a coke bottle) to the central, right, and left visual field. Participants had to decide whether the presented stimulus was fatter or thinner than the real body/object, and thus compare the presented picture with the stored representation of the stimulus from memory. From these data we extracted the amount of image distortion at which participants judged the various stimuli to be veridical. We found that right visual field presentations (initial left hemisphere processing) revealed a general "fatter" bias, which was more evident for bodies than for objects. Crucially, a "fatter" bias with own body presentations in the left visual field (initial right hemisphere processing) was only found for women. Our findings suggest that right visual field presentation results in a general size overestimation, and that this overestimation is more pronounced for bodies than for objects. Moreover, the particular "fatter" bias after own body presentations to the left visual field in women supports the notion of a specific role of the right hemisphere in sex-specific body image distortion.

On the genesis of unilateral micrographia of the progressive type

We report a patient who, following a focal ischemic lesion of the left basal ganglia, developed right hand micrographia characterised by progressive reduction of letter size during writing (progressive micrographia). The patient did not show relevant cognitive impairments, but achieved pathological scores in tests for verbal fluency, and cognitive flexibility and monitoring. A systematic investigation of the writing performances demonstrated that micrographia showed a clear length effect in whatever writing style or task, while it was not observed in drawing, or in left hand writing to a comparable extent. Right hand progressive micrographia was not affected by a concurrent motor and cognitive load; instead, switching between two kinds of allographic responses and presenting one letter at a time in copying tasks reduced severity of micrographia significantly. These findings support the view that progressive micrographia in our patient could be ascribed to a defect in regulating the motor output on the basis of self-generated strategies. This conclusion would be consistent with neuroimaging evidence about the role of the basal ganglia in the control of motor sequencing, and could suggest that progressive micrographia might be associated with specific executive defects.