Handwriting Posture Research Articles

Posición anómala de la mano para la escritura en los niños con síndrome de déficit de atención e hiperactividad

To present a developmental coordination disorder in children with attention deficit/hyperactivity syndrome (ADHS) characterized by anomalous handwriting posture of hands and fingers.Forty-five children who presented with ADHS were studied (39 males and 6 females) with ages ranging from 6 to 16 years (average 10.8 years) and an analysis of the position of the hands and fingers during handwriting was made within the context of a complete neurological evaluation.Only 2 of the 6 hyperactive patients showed a discrete anomalous posture of the fingers, with normality in the other four patients. Seventeen of the 25 children (68%) with ADHS combined type showed poor posture of the fingers when writing. Among the 14 children with ADHS attention deficit type, 8 had abnormal posture when using a pencil, and 4 had shown the problem several years before consulting, and the problem had disappeared after local orthopedic treatment. All 4 left-handed children (3 females and 1 male) presented abnormal posture of the fingers when writing.Evaluation of the anomalous posture of the fingers when writing of patients with ADHS is a test that we commonly use because it is easy to do, the patients collaborate very well to do it and uncovers very early the developmental coordination disorder. The anomalous posture is associated with other coordination disorders and problems of muscular tone such as splay-foot, genu recurvatum, problems with jumping, walking on one foot, etc. in most patients.

An X‐linked three allele model of hand preference and hand posture for writing

This paper describes a genetic model of hand preferences for writing and for handwriting posture (HWP). The challenge of devising an X‐linked model for these aspects of human handedness was posed by the results of a large family handedness study (McKeever, 2000) that showed evidence of such linkage. Because X‐linkage for handedness has been widely regarded as untenable, the prospects for developing such a model were not initially encouraging, but ultimately a viable model did suggest itself. Family studies of handedness and leading theories of handedness are briefly described, as is some of the research on HWP motivated by the theory of Levy and Nagylaki (1972). It is argued that there is evidence that HWP reflects a biological dictate and not just individual “choices” or “adaptations” to writing in a left‐to‐right direction with the left hand. The model proposes that inverted handwriting posture is not necessarily highly related to speech and language lateralities of sinistrals, but that it reveals an interhemispheric mediation of writing. It is hypothesised that it reflects a specialisation of the left angular gyrus (with some possible extension into the supramarginal gyrus) for the storage of movement and timing sequences of cursive writing, and right hemisphere motor programming of the motor output of writing. It is also argued that no family handedness study conducted to date is adequate for testing the predictions of extant handedness theories, and the often wide variations between the results of family handedness studies are noted. It is suggested that fMRI studies could definitively test the HWP hypotheses of the model and that the hypothesis of X‐linkage could be tested definitively should studies of the human genome identify a gene for handedness.

Inverted Handwriting Posture in Left Handers is Related to Familial Sinistrality Incidence

McKeever (1979) reported that left handers who wrote with an inverted handwriting posture (IHP) had a higher incidence of left handedness in their families than did left handers who wrote with a non-inverted handwriting posture (NHP). Parlow and Kinsbourne (1981), however, failed to find a relationship between handwriting posture (HWP) and positive familial sinistrality (FS+). McKeever had classified his left handed subj ects according to whether they had several, one, or no left handers among their first degreee relatives and biologically-related second degree relatives. Parlow and Kinsbourne classified subjects as FS− or FS+ on the basis of first degree relatives and did not inquire about the handedness of second degree relatives. In the present study, handedness for writing of all first and second degree relatives was recorded for 216 NHP and 255 IHP left handers. Results showed a significant association of HWP and FS factors when second degree relatives were considered, but not when second degree relative handedness was ignored. The relationship was strongest within the maternal family line, where the proportion of left handers was more than twice as high for the IHP as for the NHP group. These findings suggest that HWP may well be of some importance for a complete understanding of the cerebral organization of left handers.

Null hypothesis disrespect in neuropsychology: dangers of alpha and beta errors.

To understand why there are so many inconsistencies and contradictory findings among hemispheric-asymmetry studies, data were analyzed from a large study of 300 left-handers. These data included information on familial sinistrality (FS), handwriting posture (HPO), a measure of cognitive performance, and five measures of hemispheric specialization. Using computer simulation methodology, 40 independent samples of 36 to 65 subjects each were drawn randomly with replacement. The sample data were analyzed and the results compared to those of the parent "population." Often, the samples poorly reflected the parent "population," and some procedures substantially inflated error rates. These procedures are discussed and specific guidelines suggested. These results are also discussed in the broader context of the necessity for investigators in neuropsychology to differentiate between the statistical and clinical significance of research findings; and to develop a more positive attitude toward the design, execution, and publication of replication studies.

Hand inversion in sinistrals and lateral preference: Comments on Searleman, Porac, and Coren (1984)

A reanalysis of data from left-handers presented by A. Searleman, C. Porac, and S. Coren, (1984, Brain and Cognition, 3, 86–93) cautions against premature conclusions that an inverted handwriting posture is more prevalent for sinistral men with leftward lateral preferences and for women with rightward or mixed lateral preferences. Although this may eventually prove to be true, the findings of Searleman et al. (1984) are insufficient for supporting this inference.

Can a reaction time paradigm simultaneously index arm position effects, spatial compatibility effects, and neural pathway effects? Comments on Bradshaw, Nettleton and Spehr

Bradshaw, Nettleton and Spher ( Neuropsychologia 20, 605–609, 1982) recently claimed to have disconfirmed earlier conclusions that left-handers who use the inverted handwriting posture have an anomalous visuomotor organization. However, their reaction time paradigm generated massive spatial compatibility effects, and their inferences regarding neural pathway effects have neither empirical nor theoretical support and are predicted on an unverified and unlikely assumption.

Writing postures in left-handers: Inverters are hand-crossers

A behavioural approach shows that the inverted hand-writing posture typical of many left-handers is one element of a well-patterned bimanual strategy including (i) counterclockwise rotation of the page; (ii) horizontal orientation of the active forearm on the page; and (iii) positioning of the non-writing hand just below the beginning of the line of writing. The strategy as a whole is liable to represent an adaptation to the necessity of writing with an adduction movement, rather than the symptom of any neurological particularity.

Inverted versus straight handwriting posture: a family study.

Familial resemblances in handwriting posture, whether straight or inverted, were studied in a sample of 450 families. A significant increase in the percentage of inverted writers among offspring occurred in families where at least one parent was an inverted writer. However, generational and gender differences in the incidence of the behavior, in addition to the familial similarities, suggest that a complex, multicausal mechanism may be involved in the formation of this behavior.

Further evidence of the absence of measurable interhemispheric transfer time in left-handers who employ an inverted handwriting posture

We previously had found that left-handers who employed the inverted handwriting posture (IHP) showed no significant manual reaction time difference between homolateral and heterolateral stimulus/response-hand conditions, whereas those employing the noninverted handwriting posture (NHP) did (McKeever & Hoff, 1979). The IHP sinistrals had also shown a pattern of visual-field/response-hand-condition latencies that suggested that they might have a “disconnection” of visual and manual motor areas within the left hemisphere. The results reported here replicate the absence of a homolateral-heterolateral-conditions difference in IHP sinistrals, but not a pattern suggestive of disconnection.

Handwriting position and hemispheric asymmetry in right-handers

Right-handers who write with an inverted writing posture ( N=8) were compared to right-handers who write in the normal fashion ( N = 16) on tests of handedness and hemispheric asymmetry. Inverted writers showed the same laterality effects as normal writers for dot location and the recognition of visually-presented nonsense syllables. In dichotic listening, inverted writers were much more likely to show a left-ear superiority than were normal writers. They also were more strongly right-handed on a speeded performance test, but not in hand preference. This pattern is quite different from that obtained with left-handers, and suggests that the inverting handwriting posture has a different basis in right-handers than in left-handers.

The relationship between birth stress and writing hand posture

Variations in handwriting posture (inverted versus noninverted) were measured in 1203 individuals for whom birth histories, based upon retrospective maternal reports, were available. A history of birth complications was associated with an increased incidence of inverted handwriting posture. Effects interacted with sex and hand preference; the largest difference in handwriting posture between the birth-stressed and non-birth-stressed groups occurred in left-handers and in males.

Left-handedness and spatial reasoning abilities: The deficit hypothesis revisited

Left-handers with an inverted handwriting posture have been found by Levy and Reid to have relatively bilateral representation of tachistoscopically tested verbal and spatial functions. On the assumption that such bilateral representation is inefficient, it was hypothesized that left-inverted subjects (N = 20) would score lower than left- and right-handers with normal handwriting postures (Ns = 64, 66 respectively) on spatial reasoning. Results were consistent with the hypothesis. Possible alternative explanations and directions for future research are outlined.

Evidence of a possible isolation of left hemisphere visual and motor areas in sinistrals employing an inverted handwriting posture

Levy's hypothesis of ipsilateral motor control of the lateral distal musculature in left handers employing an inverted handwriting posture was tested in a true simple reaction time paradigm. Left-handers employing a non-inverted handwriting posture (NHP) showed performances consistent with normal (contralateral) motor control organization. Inverted handwriting posture (IHP) sinistrals showed performances that were not consistent with Levy's hypothesis nor with the simple hypothesis of normal (contralateral) control. The results for IHP sinistrals were compatible with a model of stimulus-response mediation which posits contralateral motor control and an intrahemispheric “disconnection” of left hemisphere visual areas from left hemisphere manual motor areas. The hypothesis that IHP sinistrals must utilize interhemispheric pathways for motor responses to stimuli channeled to, or formulated in, the left hemisphere was discussed in relation to the hypothesis of topographic inversion consequent to transcallosal relay. The proposed model suggests that hand inversion in writing is an accommodation to the consequences of interhemispheric relay and not to ipsilateral motor control.

Differential Finger Movements and Hand Preference

In an attempt to replicate a study by Kimura and Vanderwolf (1970), normal left-handed and right-handed subjects were asked to flex a single finger or pairs of fingers at the middle joint. Both hands were found to be equally proficient at this task and no differences between right- and left-handers were found. When left-handers were divided into inverters and non-inverters according to hand-writing posture, a left hand superiority was a found for the right-handed and the left-inverted subjects, while the left-non-inverters showed a right hand superiority. Paired finger flexion was found to be more useful in discriminating between the handedness groups. These findings support the idea that the neural mechanism for hand preference is not based on an asymmetry in the control of fine movement. They also support the theory that two separate groups of left-handers exist, and the they can be differentiated by their handwriting postures.