Evaluation of Handwriting Movement Kinematics: From an Ecological to a Magnetic Resonance Environment

Assessment of children's writing features: A pilot method study of pen-grip kinetics and writing surface pressure

The writing process is a complex task involving dexterous manipulation of the writing instrument by the hand digits and biomechanical ergonomic factors that contribute to handwriting efficiency and productivity. We describe a pilot study using an instrumented writing apparatus - a sensor (pen) and a digitized writing surface (tablet) - to measure the pen-grip kinetics (digit forces) and the pen pressure applied to the tablet during a writing task. Eight elementary school students with no handwriting difficulties copied a short story. The mean digit forces on the pen were compared with the mean pen pressure on the tablet at five interval points. Results revealed that the digit forces on the pen were significantly stronger than the pen pressure on the tablet. Results also showed significantly less digit-force variability throughout the writing task than the pen-pressure variability on the writing surface, which significantly lessened toward the end of the writing task. Information on these properties can broaden understanding of the elements that influence nonproficient handwriting in children with dysgraphia. Results also indicate the possible efficacy of a therapeutic tool for handwriting assessment and intervention using objective measurements during writing, warranting future studies with children with and without dysgraphia.

Neural Correlates of Executed Compared to Imagined Writing and Drawing Movements: A Functional Magnetic Resonance Imaging Study

Objective

In this study we used functional magnetic resonance imaging (fMRI) to investigate whether motor imagery (MI) of handwriting and circle drawing activates a similar handwriting network as writing and drawing itself.

Methods

Eighteen healthy right-handed participants wrote the German word “Wellen” and drew continuously circles in a sitting (vertical position) and lying position (horizontal position) to capture kinematic handwriting parameters such as velocity, pressure and regularity of hand movements. Afterward, they performed the same tasks during fMRI in a MI and an executed condition.

Results

The kinematic analysis revealed a general correlation of handwriting parameters during sitting and lying except of pen pressure during drawing. Writing compared to imagined writing was accompanied by an increased activity of the ipsilateral cerebellum and the contralateral sensorimotor cortex. Executed compared to imagined drawing revealed elevated activity of a fronto–parieto-temporal network. By contrasting writing and drawing directly, executed writing induced an enhanced activation of the left somatosensory and premotor area. The comparison of the MI of these tasks revealed a higher involvement of occipital activation during imagined writing.

Conclusion

The kinematic results pointed to a high comparability of writing in a vertical and horizontal position. Overall, we observed highly overlapping cortical activity except of a higher involvement of motor control areas during motor execution. The sparse difference between writing and drawing can be explained by highly automatized writing in healthy individuals.

Deficient Interhemispheric Connectivity Underlies Movement Irregularities in Parkinson's Disease

BACKGROUND

Movement execution is impaired in patients with Parkinson's disease. Evolving neurodegeneration leads to altered connectivity between distinct regions of the brain and altered activity at interconnected areas. How connectivity alterations influence complex movements like drawing spirals in Parkinson's disease patients remains largely unexplored.

OBJECTIVE

We investigated whether deteriorations in interregional connectivity relate to impaired execution of drawing.

METHODS

Twenty-nine patients and 31 age-matched healthy control participants drew spirals with both hands on a digital graphics tablet, and the regularity of drawing execution was evaluated by sample entropy. We recorded resting-state fMRI and task-related EEG, and calculated the time-resolved partial directed coherence to estimate effective connectivity for both imaging modalities to determine the extent and directionality of interregional interactions.

RESULTS

Movement performance in Parkinson's disease patients was characterized by increased sample entropy, corresponding to enhanced irregularities in task execution. Effective connectivity between the motor cortices of both hemispheres, derived from resting-state fMRI, was significantly reduced in Parkinson's disease patients in comparison to controls. The connectivity strength in the nondominant to dominant hemisphere direction in both modalities was inversely correlated with irregularities during drawing, but not with the clinical state.

CONCLUSION

Our findings suggest that interhemispheric connections are affected both at rest and during drawing movements by Parkinson's disease. This provides novel evidence that disruptions of interhemispheric information exchange play a pivotal role for impairments of complex movement execution in Parkinson's disease patients.

Right Inferior Parietal Lobule Activity Is Associated With Handwriting Spontaneous Tempo

Handwriting is a complex activity including motor planning and visuomotor integration and referring to some brain areas identified as "writing centers." Although temporal features of handwriting are as important as spatial ones, to our knowledge, there is no evidence of the description of specific brain areas associated with handwriting tempo. People with multiple sclerosis (PwMS) show handwriting impairments that are mainly referred to as the temporal features of the task. The aim of this work was to assess differences in the brain activation pattern elicited by handwriting between PwMS and healthy controls (HC), with the final goal of identifying possible areas specific for handwriting tempo. Subjects were asked to write a sentence at their spontaneous speed. PwMS differed only in temporal handwriting features from HC and showed reduced activation with a subset of the clusters observed in HC. Spearman's correlation analysis was performed between handwriting temporal parameters and the activity in the brain areas resulting from the contrast analysis, HC > PwMS. We found that the right inferior parietal lobule (IPL) negatively correlated with the duration of the sentence, indicating that the higher the right IPL activity, the faster the handwriting performance. We propose that the right IPL might be considered a "writing tempo center."

Tablet Technology for Writing and Drawing during Functional Magnetic Resonance Imaging: A Review

Functional magnetic resonance imaging (fMRI) is a powerful modality to study brain activity. To approximate naturalistic writing and drawing behaviours inside the scanner, many fMRI-compatible tablet technologies have been developed. The digitizing feature of the tablets also allows examination of behavioural kinematics with greater detail than using paper. With enhanced ecological validity, tablet devices have advanced the fields of neuropsychological tests, neurosurgery, and neurolinguistics. Specifically, tablet devices have been used to adopt many traditional paper-based writing and drawing neuropsychological tests for fMRI. In functional neurosurgery, tablet technologies have enabled intra-operative brain mapping during awake craniotomy in brain tumour patients, as well as quantitative tremor assessment for treatment outcome monitoring. Tablet devices also play an important role in identifying the neural correlates of writing in the healthy and diseased brain. The fMRI-compatible tablets provide an excellent platform to support naturalistic motor responses and examine detailed behavioural kinematics.

Evaluation of the Reliability and Validity of the Brazilian Version of the Here’s How I Write:

OBJECTIVE. Our objective was to translate the Here’s How I Write: A Child’s Self-Assessment and Goal Setting Tool (HHIW) to Portuguese; adapt it to the Brazilian culture; and analyze its reliability, validity, and clinical feasibility.

METHOD. The study was developed in two steps: adaptation of the HHIW to Brazilian Portuguese, followed by experimental application to examine its validity and reliability. The participants were 60 children and their teachers, divided into two groups: Group 1, whose members had handwriting difficulties, and Group 2, whose members did not.

RESULTS. Children with poor handwriting scored lower on the HHIW for both self- and teacher report. Test–retest reliability of the children’s (.96) and teachers’ (.93) questionnaires as well as internal consistency (.91 and .95, respectively) were excellent. There was good agreement (.74) between the children’s and teachers’ total scores.

CONCLUSIONS. This study adds further evidence of validity and reliability and supports the international use of the HHIW. The HHIW is a useful resource to engage children and teachers in a collaborative relationship to improve handwriting.

The kinematics of handwriting movements as expression of cognitive and sensorimotor impairments in people with multiple sclerosis

Handwriting is an important activity of daily living, which requires sensorimotor and cognitive skills that could deteriorate in presence of neurological diseases. Handwriting impairments are common in people with multiple sclerosis (PwMS). Aims of the present study were to characterize handwriting movement features of PwMS in comparison with those of healthy adults, and to evaluate the relationship between kinematic parameters of handwriting movements and the results of the assessment of cognitive and motor domains. A new handwriting evaluation methodology was applied to quantify handwriting features of 19 PwMS and 22 age-matched healthy controls who were required to write a sentence on a digitizing tablet. Kinematic parameters of the sentence and of the strokes were used to evaluate handwriting performance. PwMS showed an altered handwriting kinematics with respect to healthy controls: higher movement duration, fragmented velocity profile and higher jerk. Furthermore, motor abilities and cognitive status of PwMS were related to handwriting parameters in accordance with the evidence that MS is a multifactorial disease affecting different domains. These results suggested that the proposed methodology might be a valuable tool to quantitatively assess handwriting impairments and the efficacy of handwriting treatments in PwMS.