OBJECTIVE:
The overall goal of this proposal is to provide new insights into long-term motor learning by studying patients with focal hand dystonia (FHD) and healthy controls. Long-term motor learning has never been studied in FHD patients. Our central hypothesis is that dystonia is caused by abnormal long-term motor learning. Specifically, the aims of this study are:
1. To show that FHD patients have abnormal motor learning, and in particular, have slower motor skill acquisition compared to healthy controls.
2. To show that FHD patients have difficulty in performing newly acquired motor skills automatically.
3. To study brain dynamics (i.e. cortico-cortical connectivity and motor cortex excitability) in FHD patients and healthy controls while learning a sequence of finger movements over a 3-month period of time.
STUDY POPULATION:
We will follow 10 patients with FHD affecting their dominant hand and 10 healthy volunteers.
DESIGN:
We have devised this case-control experimental study to evaluate the long-term learning of sequential finger movements in FHD patients and healthy controls. We will study FHD patients and healthy volunteers for 12 weeks as they learn a 4 finger sequence of eight key presses with their left hand using a metronome to mark the rhythm. All subjects will be right-handed and age-matched. They will be asked to practice this sequence of 8 key presses daily for 30 minutes for the first week and then for 15 minutes for the remainder of the study. For the first 3 weeks of the study, subjects will come to the Clinical Center (CC) 10 times at regular intervals based on their availability. They will practice daily at the CC or at home during this period. They will then come to the CC every 2 weeks (plus or minus 3 days) for the remainder of the study while practicing daily for 15 minutes. At each visit, learning will be assessed by measuring the sequence error rates (SER) and variability in the interval between key presses. All subjects will be asked to keep a log of daily practice during the 12 weeks. At each visit patients will be carefully questioned and evaluated for the development of abnormal movement patterns suggestive of early dystonia.
OUTCOME MEASURES:
The primary outcome of this study will be to measure the SER at baseline, week 4 and week 12 using 20 consecutive trials of the 8 sequences. We will measure multiple secondary outcomes: (a) variability in the interval between key presses; (b) automaticity of the movement evaluated by a dual task; (c) constrained action evaluated by a thinking task; (d) transcranial magnetic stimulation (TMS) and electroencephalography (EEG) studies to explore changes in brain physiology.
