Micrographia in Parkinson's disease

McLennan, James E.; Nakano, KK; Tyler, H.R.; Schwab, Robert S.

doi:10.1016/0022-510x(72)90002-0

Cited by 161 publications

(128 citation statements)

References 14 publications

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“…In some 10-15% of patients suffering from Parkinsonism the size of handwriting is visibly reduced, a phenomenon known as "micrographia" (McLennan, Nakano, Tyler, & Schwab, 1972). Only a few of the patients studied by McLennen et al were able to increase voluntarily the size of their writing, and those who managed could only sustain it for a short time.…”

Section: Execution Disorders I: Micrographia In Parkinson's Diseasementioning

confidence: 97%

Normal writing processes and peripheral acquired dysgraphias

Ellis

1988

Language and Cognitive Processes

163

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Section: Execution Disorders I: Micrographia In Parkinson's Diseasementioning

confidence: 97%

Normal writing processes and peripheral acquired dysgraphias

Ellis

1988

Language and Cognitive Processes

163

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“…The multifinger coordination paradigm has been chosen because it is vital for many activities of daily living. Moreover, hand function in PD is impaired (e.g., micrographia; McLennan et al 1972;Viviani et al 2009) and known as one of the early symptoms of PD.…”

mentioning

confidence: 99%

Changes in multifinger interaction and coordination in Parkinson's disease

Park

Lewis

et al. 2012

Journal of Neurophysiology

122

135

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In this study, we tested several hypotheses related to changes in finger interaction and multifinger synergies during multifinger force production tasks in Parkinson's disease. Ten patients with Parkinson's disease, mostly early stage, and 11 healthy control subjects participated in the study. Synergies were defined as covaried adjustment of commands to fingers that stabilized the total force produced by the hand. Both Parkinson's disease patients and control subjects performed accurate isometric force production tasks with the fingers of both the dominant and nondominant hands. The Parkinson's disease patients showed significantly lower maximal finger forces and higher unintended force production (enslaving). These observations suggest that changes in supraspinal control have a major effect on finger individuation. The synergy indexes in the patients were weaker in both steady-state and cyclic force production tasks compared with the controls. These indexes also were stronger in the left (nondominant) hand in support of the dynamic-dominance hypothesis. Half of the patients could not perform the cyclic task at the highest frequency (2 Hz). Anticipatory adjustments of synergies prior to a quick force pulse production were delayed and reduced in the patients compared with the controls. Similar differences were observed between the asymptomatic hands of the patients with symptoms limited to one side of the body and matched hands of control subjects. Our study demonstrates that the elusive changes in motor coordination in Parkinson's disease can be quantified objectively, even in patients at a relatively early stage of the disease. The results suggest an important role of the basal ganglia in synergy formation and demonstrate a previously unknown component of impaired feedforward control in Parkinson's disease reflected in the reduced and delayed anticipatory synergy adjustments.

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“…Consequently, as part of the identification of new and objective biomarkers to help diagnose PD at its earliest stage and manage disease progression, handwriting analysis has been proposed [5][6][7]. Until recently, there was a consensus regarding the existence of a specific behavioral feature in PD handwriting, so-called micrographia.…”

Section: Micrographia In Parkinson's Disease: Too Restrictive a Definmentioning

confidence: 99%

“…Micrographia has further been divided into two types: consistent micrographia, presenting as a global reduction in writing size, and progressive micrographia, which results from an inability to sustain normal sized letters for more than a few characters [9,10]. The occurrence of micrographia varies between studies: 10-15 [11], 29 [12], 44 [9] or even 63.2% [13]. This large range mainly results from the number of patients studied, the heterogeneity of symptoms and the nature of the analyses (quantitative vs self-questionnaires).…”

Section: Micrographia In Parkinson's Disease: Too Restrictive a Definmentioning

confidence: 99%