title: Micrographia, much beyond the writer's hand.
abstract: 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.
  
  
  
  A systematic review of the existing literature was performed.
  
  
  
  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.
  
  
  
  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.
authors.affiliation: Department of Neurology and Neurosurgery, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Center of Advanced Technologies in Rehabilitation, Sheba Medical Center, Tel Hashomer, Israel; Department of Applied Mathematics and Computer Science, The Weizmann Institute of Science, Rehovot, Israel. Electronic address: inzelber@post.tau.ac.il.
authors.forename: Rivka
authors.initials: R
authors.lastname: Inzelberg
authors.affiliation: Department of Pharmacology and Physiology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel; Center of Advanced Technologies in Rehabilitation, Sheba Medical Center, Tel Hashomer, Israel; Gonda Brain Research Center, Bar Ilan University, Ramat Gan, Israel. Electronic address: meir.plotnik@sheba.health.gov.il.
authors.forename: Meir
authors.initials: M
authors.lastname: Plotnik
authors.affiliation: Department of Applied Mathematics and Computer Science, The Weizmann Institute of Science, Rehovot, Israel. Electronic address: naama.kadmon@weizmann.ac.il.
authors.forename: Naama Kadmon
authors.initials: NK
authors.lastname: Harpaz
authors.affiliation: Department of Applied Mathematics and Computer Science, The Weizmann Institute of Science, Rehovot, Israel. Electronic address: tamar.flash@weizmann.ac.il.
authors.forename: Tamar
authors.initials: T
authors.lastname: Flash
mesh_terms: D000381:Agraphia / Q000175:diagnosis* / Q000209:etiology / Q000628:therapy; D001479:Basal Ganglia / Q000473:pathology*; D006236:Handwriting; D006801:Humans; D018476:Hypokinesia / Q000175:diagnosis / Q000209:etiology / Q000628:therapy; D009415:Nerve Net / Q000473:pathology*; D010300:Parkinson Disease / Q000150:complications / Q000175:diagnosis / Q000628:therapy
keywords: Handwriting; Micrographia; Parkinson's disease; Scaling