title: A computational model of Parkinsonian handwriting that highlights the role of the indirect pathway in the basal ganglia.
abstract: Parkinsonian handwriting is typically characterized by micrographia, jagged line contour, and unusual fluctuations in pen velocity. In this paper we present a computational model of handwriting generation that highlights the role of the basal ganglia, particularly the indirect pathway. Whereas reduced dopamine levels resulted in reduced letter size, transition of STN-GPe dynamics from desynchronized (normal) to synchronized (PD) condition resulted in increased fluctuations in velocity in the model. We also present handwriting data from PD patients (n=34) who are at various stages of disease and had taken medication various lengths of time before the handwriting sessions. The patient data are compared with those of age-matched controls. PD handwriting statistically exhibited smaller size and larger velocity fluctuation compared to normal handwriting.
authors.affiliation: Machine Learning Group, IDIAP Research Institute, CH-1920 Martigny, Switzerland. Gangadhar.Garipelli@idiap.ch
authors.forename: G
authors.initials: G
authors.lastname: Gangadhar
authors.forename: D
authors.initials: D
authors.lastname: Joseph
authors.forename: A V
authors.initials: AV
authors.lastname: Srinivasan
authors.forename: D
authors.initials: D
authors.lastname: Subramanian
authors.forename: R G
authors.initials: RG
authors.lastname: Shivakeshavan
authors.forename: N
authors.initials: N
authors.lastname: Shobana
authors.forename: V S
authors.initials: VS
authors.lastname: Chakravarthy
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001479:Basal Ganglia / Q000503:physiopathology*; D003342:Corpus Striatum / Q000503:physiopathology; D004298:Dopamine / Q000097:blood; D005260:Female; D006236:Handwriting; D006801:Humans; D007194:India; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D008959:Models, Neurological; D009043:Motor Activity / Q000502:physiology; D010300:Parkinson Disease / Q000097:blood / Q000503:physiopathology*; D012016:Reference Values; D013378:Substantia Nigra / Q000503:physiopathology; D020531:Subthalamic Nucleus / Q000503:physiopathology
chemical_list: D004298:Dopamine