title: A novel method for the quantification of key components of manual dexterity after stroke.
abstract: BACKGROUND
  A high degree of manual dexterity is a central feature of the human upper limb. A rich interplay of sensory and motor components in the hand and fingers allows for independent control of fingers in terms of timing, kinematics and force. Stroke often leads to impaired hand function and decreased manual dexterity, limiting activities of daily living and impacting quality of life. Clinically, there is a lack of quantitative multi-dimensional measures of manual dexterity. We therefore developed the Finger Force Manipulandum (FFM), which allows quantification of key components of manual dexterity. The purpose of this study was (i) to test the feasibility of using the FFM to measure key components of manual dexterity in hemiparetic stroke patients, (ii) to compare differences in dexterity components between stroke patients and controls, and (iii) to describe individual profiles of dexterity components in stroke patients.
  
  
  METHODS
  10 stroke patients with mild-to-moderate hemiparesis and 10 healthy subjects were recruited. Clinical measures of hand function included the Action Research Arm Test and the Moberg Pick-Up Test. Four FFM tasks were used: (1) Finger Force Tracking to measure force control, (2) Sequential Finger Tapping to measure the ability to perform motor sequences, (3) Single Finger Tapping to measure timing effects, and (4) Multi-Finger Tapping to measure the ability to selectively move fingers in specified combinations (independence of finger movements).
  
  
  RESULTS
  Most stroke patients could perform the tracking task, as well as the single and multi-finger tapping tasks. However, only four patients performed the sequence task. Patients showed less accurate force control, reduced tapping rate, and reduced independence of finger movements compared to controls. Unwanted (erroneous) finger taps and overflow to non-tapping fingers were increased in patients. Dexterity components were not systematically related among each other, resulting in individually different profiles of deficient dexterity. Some of the FFM measures correlated with clinical scores.
  
  
  CONCLUSIONS
  Quantifying some of the key components of manual dexterity with the FFM is feasible in moderately affected hemiparetic patients. The FFM can detect group differences and individual profiles of deficient dexterity. The FFM is a promising tool for the measurement of key components of manual dexterity after stroke and could allow improved targeting of motor rehabilitation.
authors.affiliation: FR3636 CNRS, Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France. mteremetz@gmail.com.
authors.forename: Maxime
authors.initials: M
authors.lastname: Térémetz
authors.affiliation: Service de Médecine Physique et de Réadaptation, Université Paris Descartes, Hôpital Sainte-Anne, 75014, Paris, France. f.colle@ch-sainte-anne.fr.|Centre de Psychiatrie et Neurosciences, Inserm U894, 75014, Paris, France. f.colle@ch-sainte-anne.fr.
authors.forename: Florence
authors.initials: F
authors.lastname: Colle
authors.affiliation: Service de Médecine Physique et de Réadaptation, Université Paris Descartes, Hôpital Sainte-Anne, 75014, Paris, France. S.HAMDOUN@ch-sainte-anne.fr.
authors.forename: Sonia
authors.initials: S
authors.lastname: Hamdoun
authors.affiliation: FR3636 CNRS, Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France. marc.maier@parisdescartes.fr.|Université Paris Diderot, Sorbonne Paris Cité, 75013, Paris, France. marc.maier@parisdescartes.fr.
authors.forename: Marc A
authors.initials: MA
authors.lastname: Maier
authors.affiliation: FR3636 CNRS, Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France. pavel.lindberg@inserm.fr.|Centre de Psychiatrie et Neurosciences, Inserm U894, 75014, Paris, France. pavel.lindberg@inserm.fr.
authors.forename: Påvel G
authors.initials: PG
authors.lastname: Lindberg
mesh_terms: D000328:Adult; D000368:Aged; D001132:Arm / Q000503:physiopathology; D005260:Female; D005385:Fingers / Q000503:physiopathology; D006225:Hand / Q000503:physiopathology; D018737:Hand Strength; D006801:Humans; D008297:Male; D008875:Middle Aged; D009048:Motor Skills; D010291:Paresis / Q000503:physiopathology / Q000534:rehabilitation; D011597:Psychomotor Performance; D020521:Stroke / Q000503:physiopathology*