title: Markers for upper limb dysfunction in Amyotrophic Lateral Sclerosis using analysis of typing activity.
abstract: OBJECTIVE
  Assistive devices based on keyboard access support communication and control tools for patients with Amyotrophic Lateral Sclerosis (ALS). The aim of this work was to explore movement activity in the use of keyboards and identify markers for upper limb (UL) dysfunction.
  
  
  METHODS
  We present a longitudinal study including 19 ALS patients, followed for 2-20 months. Typing activity was recorded with an accelerometer placed on the posterior part of patients' index finger. Participants performed the same 10-word typing task (2-6 assessments). Time and acceleration during keystroke were the main outcomes of this study. Patients were compared with 20 healthy subjects and 6 patients with other neuromuscular disorders.
  
  
  RESULTS
  During disease progression, mean time in holding down a key increased and was longer than in control subjects. Acceleration at key press and key release decreased with progression of UL dysfunction. Delay between tapping and pressing down each key increased with UL dysfunction.
  
  
  CONCLUSIONS
  Delay in pressing and releasing keys are markers of UL dysfunction in ALS. The decrease in the acceleration of movements related to keystroke can contribute to monitor disease progression.
  
  
  CONCLUSIONS
  Typing activity can be explored to access remotely and continuously to ALS progression by patients who use assistive communication devices.
authors.affiliation: Translational Clinical Physiology Unit, Instituto de Medicina Molecular, Institute of Physiology - Faculty of Medicine, University of Lisbon, Portugal. Electronic address: arml@campus.ul.pt.
authors.forename: Ana
authors.initials: A
authors.lastname: Londral
authors.affiliation: Translational Clinical Physiology Unit, Instituto de Medicina Molecular, Institute of Physiology - Faculty of Medicine, University of Lisbon, Portugal.
authors.forename: Susana
authors.initials: S
authors.lastname: Pinto
authors.affiliation: Translational Clinical Physiology Unit, Instituto de Medicina Molecular, Institute of Physiology - Faculty of Medicine, University of Lisbon, Portugal; Department of Neurosciences, Hospital de Santa Maria - CHLN, Lisbon, Portugal.
authors.forename: Mamede
authors.initials: M
authors.lastname: de Carvalho
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000690:Amyotrophic Lateral Sclerosis / Q000175:diagnosis* / Q000503:physiopathology*; D003201:Computers; D018450:Disease Progression; D005260:Female; D005385:Fingers / Q000503:physiopathology*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology; D009068:Movement / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology
keywords: Amyotrophic Lateral Sclerosis; Assistive devices; Functional assessment; Home monitoring; Upper limbs dysfunction