Mode of hand training determines cortical reorganisation: a randomized controlled study in healthy adults.
OBJECTIVE
To evaluate two commonly used forms of hand training with respect to influence on dexterity and cortical reorganization.


METHODS
Thirty healthy volunteers (mean age 24.2 years).


METHODS
The subjects were randomized to 25 min of shaping exercises or general activity training of the non-dominant hand. The dexterity and the cortical motor maps (number of excitable positions) of the abductor pollicis brevis muscle were evaluated pre- and post-training by the Purdue Peg Board test and transcranial magnetic stimulation, respectively.


RESULTS
After shaping exercises the dexterity increased significantly (p < or = 0.005) for both hands, mostly so in the non-dominant hand. The cortical motor map of the abductor pollicis brevis muscle shifted forwardly into the pre-motor area without expanding. After general activity training, no significant improvements in dexterity were found for the non-dominant hand. The cortical motor map of the non-dominant abductor pollicis brevis muscle expanded significantly (p = 0.03) in the posterior (sensory) direction.


CONCLUSIONS
These results indicate that shaping exercises, but not general activity training, increase dexterity of the trained non-dominant hand in parallel with a shift of location of active transcranial magnetic stimulation positions. Shifts of active cortical areas might be important for the interpretation of brain plasticity in common behavioural tasks.
Brogårdh
Christina
C
Rehabilitation Medicine, Department of Community Medicine and Rehabilitation, Umeå University, Umeå, Sweden. christina.brogardh@skane.se
Johansson
Fredrik W
FW
Nygren
Frida
F
Sjölund
Bengt H
BH
D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006225:Hand / Q000502:physiology*; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology; D009048:Motor Skills / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology; D050781:Transcranial Magnetic Stimulation