[Show abstract][Hide abstract] ABSTRACT: Postural instability (PI) is a disabling sign of Parkinson's disease (PD) not easily amenable to treatment with medication.
To evaluate the effects of balance training on PI in patients with PD.
A total of 64 patients with PI were randomly assigned to the experimental group (n = 33) for balance training or to the control group (n = 31) for general physical exercises. Each patient received 21 treatment sessions of 50 minutes each. Patients were evaluated by a blinded rater before and after treatment as well as 1 month posttreatment using the Berg Balance Scale (BBS), Activities-Specific Balance Confidence Scale (ABC), postural transfer test, self-destabilization of the center of foot pressure test, number of falls, Unified Parkinson's Disease Rating Scale (UPDRS), modified Hoehn and Yahr (H&Y) Staging Scale, and Geriatric Depression Scale (GDS).
At the end of treatment, the experimental group showed significant improvements in all outcome measures, except for the UPDRS and the H&Y scale. Improvement was maintained at the 1-month follow-up in all outcome measures except for the GDS. No significant changes in performance were observed in the control group.
A program of balance training can improve PI in patients with PD.
[Show abstract][Hide abstract] ABSTRACT: The only known genetic cause of early-onset primary torsion dystonia is the GAG deletion in the DYT1 gene. Due to the reduced penetrance, many mutation carriers remain clinically asymptomatic, despite the presence of subclinical abnormalities, mainly in the motor control circuitry. Our aim was to investigate whether the DYT1 mutation impairs the inner simulation of movements, a fundamental function for motor planning and execution, which relies upon cortical and subcortical systems, dysfunctional in dystonia.
DYT1 manifesting patients, DYT1 non-manifesting carriers and control subjects were asked to fixate body (hand, foot, face) or non-body (car) stimuli on a computer screen. Stimuli were presented at different degrees of orientations and subjects had to mentally rotate them, in order to give a laterality judgement. Reaction times and accuracy were collected.
DYT1 carriers, manifesting and non-manifesting dystonic symptoms, were slower in mentally rotating body parts (but not cars) than control subjects.
The DYT1 gene mutation is associated with a slowness in mental simulation of movements, independently from the presence of motor symptoms.
These findings suggest that the cognitive representation of body movements may be altered subclinically in dystonia, thus contributing to the endophenotypic trait of disease.
[Show abstract][Hide abstract] ABSTRACT: Blepharospasm is an adult-onset focal dystonia that causes involuntary blinking and eyelid spasms. Studies have shown the presence of sensory deficits associated with dystonia.
To rule out any confounding effect of muscle spasms on sensory performance in affected and unaffected body regions of patients with blepharospasm and with hemifacial spasm.
Participants (19 patients with blepharospasm, 19 patients with hemifacial spasm and 19 control subjects) were asked to discriminate between two stimuli that were either simultaneous or sequential (temporal discrimination threshold, TDT). Pairs of tactile stimuli were delivered with increasing or decreasing inter-stimulus intervals from 0 to 400 ms (in 10-ms steps) to the hands or on the skin over the orbicularis oculi muscle.
Tactile stimuli elicited similar TDTs in control subjects and patients with hemifacial spasm, but significantly higher TDTs in patients with blepharospasm, regardless of whether stimuli were applied to the orbicularis muscle or the hand.
As TDT was abnormal in unaffected body regions of patients with blepharospasm, and patients with hemifacial spasm processed tactile stimuli normally, TDT deficits in blepharospasm depend on central rather than peripheral factors. This study further supports the link between focal dystonia and impaired temporal processing of somatosensory inputs.
Journal of neurology, neurosurgery, and psychiatry 08/2008; 79(7):796-8. DOI:10.1136/jnnp.2007.131524 · 6.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Perception of limb position and motion is abnormal in Parkinson's disease (PD). Despite the fact that the processing of proprioceptive inputs is inherently temporal, most studies have assessed spatial aspects of proprioception in PD patients. Here, we use a recently described method to test whether deficits also exist in temporal discrimination of proprioceptive inputs. We induced index finger abduction or wrist flexion through percutaneous electrical stimulation of the motor point of the first dorsal interosseous muscle (FDI) or the flexor carpii radialis (FCR), respectively. Twelve patients with unilateral bradykinetic-rigid PD and 12 healthy subjects were asked to report whether pairs of stimuli separated by different time intervals produced single or double index finger abduction movement or wrist flexion. The shortest interval at which subjects reported two separated movements was considered as temporal movement discrimination threshold. Results showed that thresholds were significantly higher in PD patients than in control subjects for both FCR and FDI muscle, thus demonstrating for the first time that temporal proprioceptive processing is altered in PD.
[Show abstract][Hide abstract] ABSTRACT: We recently reported that transcutaneous electrical nerve stimulation (TENS) applied over forearm flexor muscles, a paradigm producing in physiological conditions transient changes in corticomotoneuronal excitability of forearm muscles, may improve motor symptoms in writer's cramp (WC). In the present study, we explored the possibility that one or repeated sessions of TENS might have beneficial effects on handwriting in WC by remodulating cortical excitability of forearm agonist and antagonist muscles. Motor evoked potentials (MEPs) after transcranial magnetic stimulation of the left motor cortex were recorded from the right flexor carpi radialis (FCR) and extensor carpi radialis (ECR) muscles, before and after 1 and 15 sessions of TENS applied over flexor muscles in patients and in a control group. One session of TENS induced a significant smaller reduction of MEPs from the FCR and a smaller increase of the MEPs from the ECR in patients than in normal subjects. In WC, repeated sessions of TENS had the effect to decrease MEP amplitude in the FCR and to increase it in the ECR. This modulation was paralleled by a handwriting improvement. In conclusion, repeated TENS sessions may have the effect to re-modulate excitability of the motor cortex in WC and this modulation might partially play a role in temporarily improving the handwriting.
Movement Disorders 11/2006; 21(11):1908-13. DOI:10.1002/mds.21081 · 5.68 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Although movement abnormalities are predominant symptoms of dystonia, patients also have alterations in temporal as well as spatial discrimination of cutaneous inputs. Here, we use a recently described method to test whether deficits also exist in temporal discrimination of proprioceptive inputs. Percutaneous electrical stimulation of the motor point of the first dorsal interosseous (FDI) muscle, and of the flexor carpii radialis (FCR) muscle separately, was used to produce a nonpainful contraction of the muscles that caused index finger abduction and wrist flexion, respectively. In 10 patients with writer's cramp and in 10 healthy subjects, pairs of stimuli separated by different time intervals were given and subjects were asked to report whether they perceived a single or a double index finger abduction movement or wrist flexion. The threshold value was the shortest interval at which the subjects reported two separated movements (temporal discrimination motor threshold [TDMT]). In both writer's cramp patients and controls, TDMTs were higher for FCR than for FDI. But in contrast to the reduced temporal discrimination reported for cutaneous sensation, there was no significant difference in either muscle between TDMT in patients and normal subjects. We conclude that temporal processing of muscle and cutaneous afferents is differentially affected in focal hand dystonia.
Movement Disorders 08/2006; 21(8):1131-5. DOI:10.1002/mds.20892 · 5.68 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Percutaneous electrical stimulation of the motor point of the first dorsal interosseous muscle (FDI) was used to produce a non-painful contraction of the FDI muscle that caused index finger abduction movement but no radiating cutaneous paraesthesias or sharp sensations localized to joints. Pairs of stimuli separated by different time intervals were given and subjects were asked to report whether they perceived a single or a double index finger abduction movement. The threshold value was the shortest interval for which the subjects reported two separate index finger abduction movements. Temporal discrimination movement thresholds (TDMT) were measured for both right and left hand. To assess the possible role of muscle and cutaneous afferents in temporal discrimination, we investigated the effects of high-frequency (20 Hz) electrical stimulation of the right ulnar and radial nerves on TDMT. In humans, muscle afferents from FDI are supplied by the ulnar nerve whereas the cutaneous territory overlying the muscle and joint is supplied by the radial and median nerves. Threshold values were not significantly different for right (75.1 ms) and left (75.6 ms) hands. During ulnar and to a lesser extent during radial nerve stimulation, TDMT values were significantly increased (119.2 and 93.5 ms, respectively) compared with baseline conditions (78.0 ms) whereas no changes were observed during median nerve stimulation (80.5 ms). These results suggest that muscle, and in part cutaneous, afferents contribute to temporal discrimination of a dual movement. The technique may provide a useful way of measuring temporal discrimination of kinaesthetic inputs in humans.
Experimental Brain Research 11/2005; 166(2):184-9. DOI:10.1007/s00221-005-2353-3 · 2.04 Impact Factor