Postural instability years after stroke.

BACKGROUND: Following a stroke, balance disturbances often persist despite full recovery of the paretic side. AIMS: The aims were to determine how long postural instability could be detected after stroke and the differences in post-stroke patients under and above 65 years of age. METHODS: Static and dynamic posturography (passing weights from hand to hand around the body) measurements were performed on 29 patients with stroke after 3 ± 2.4 years (≤65 years) and 4.7 ± 3.3 years. (> 65 years) compared with 38 controls. RESULTS: Only the pathway and the velocity assessed by dynamic posturography were significantly higher (p < 0.05) in the younger group of patients compared with the controls. The older group of patients had significantly elevated parameters measured by both static (p < 0.01) and dynamic posturography (p < 0.05). CONCLUSIONS: we conclude, using a sensitive and reproducible method to assess both static and dynamic adjustments to maintain balance, that postural instability is significantly greater in post-stroke patients than control subjects. This difference is demonstrable up to 4 years after stroke, despite full recovery of the affected side.

Destroyed non-dopaminergic pathways in the early stage of Parkinson's disease assessed by posturography.

BACKGROUND: The early stage of Parkinson's disease (PD) (Hoehn-Yahr (HY) I-II stages) is characterized by a negative pull test, which clinically excludes postural instability. Previous studies with dynamic posturography detected balance disturbances even at the onset of the disease but the age dependency or prediction of dyskinesia with dynamic posturography are not known. OBJECTIVE/HYPOTHESIS: We hypothesized that the postural instability evoked by dynamic posturography was part of the early stage of PD. Furthermore, we studied how we can provoke dyskinesia. METHODS: Postural instability with static and dynamic posturography (passing balls with different weights around the body) was studied in 45 patients with PD in their HY I, II stages. They were compared with 35 age-matched healthy controls. Eighteen patients with dyskinesia were involved in the study. Fourteen patients were followed for two years. RESULTS: The pathway and velocity of the movement assessed by static and the dynamic posturography were significantly higher in the group >65 years than that of age-matched healthy controls, while the group ≤65 years showed a significant increment only in the antero-posterior sway during dynamic posturography. The imbalance of patients with dyskinesia was significantly (p < 0.05) provoked by dynamic posturography compared to patients with PD without dyskinesia. The results were independent of age. CONCLUSION: Postural instability is part of the early symptoms of PD. Non-dopaminergic pathways may be involved in the early stage of PD.

Long term follow-up study of non-invasive brain stimulation (NBS) (rTMS and tDCS) in Parkinson's disease (PD). Strong age-dependency in the effect of NBS.

BACKGROUND: Transcranial magnetic stimulation (rTMS) may influence the progression of PD compared with levodopa. The long term mind modification effect of repeated rTMS and tDCS is not known, nor are the predictors for the effect of NBS. OBJECTIVE/HYPOTHESIS: We hypothesized that the regularly repeated rTMS would decrease the development of PD. Later, the treatment protocol was completed with transcranial direct current stimulation (tDCS), supposing that there is an add-on effect. NBS may differently influence motor and mental aspects of the disease. METHODS: Thirty patients with PD were followed for 3.5 years in an open study. They were stimulated with 1 Hz rTMS every half year for 1.5 years. After that the tDCS was add to the stimulation over both sides of the cerebellum for the next 2 years. UPDRS, Trail Making Test and dual tests were used. The linear regression lines of score systems and percentage of yearly increment were counted, analyzed by ANOVA. RESULTS: The yearly progression rate for UPDRS total was 2% for 3.5 years, 0.6% ≤65 years, 3.6% >65 years. The increment was around zero during the rTMS + tDCS stimulations in patients ≤65 years. The slope of the equation showed the same tendency. The individual sensitivity to the NBS was high. tTMS and tDCS >65 yrs improved pathological executive function (p < 0.0001). CONCLUSION: The motor ability in PD was maintained at the same level in patients ≤65 years with NBS for the 3.5 years in contrast to patients >65 years. The cognitive function of patients >65 yrs was favorable influenced by rTMS and tDCS. Age is the main predictor of the effect of NBS. rTMS and tDCS can slow the progression of PD without any side effects but in an age-dependent way.

Follow up study: The influence of rTMS with high and low frequency stimulation on motor and executive function in Parkinson's disease.

BACKGROUND: rTMS may influence on both cognitive and motor function in PD but the daily routine and the predictors of responders to rTMS are not known. OBJECTIVE/HYPOTHESIS: We hypothesized that the frequency and intensity of stimulation somehow relate to each other. Our goal was to select the optimal frequency with low intensity for PD. We clarified the importance of age in the effect of rTMS. METHODS: A total sixty-six patients with PD were included in the study. In an open investigation, randomly selected patients were divided into three groups. The effects of 1Hz (N=28), 5Hz (N=13) and 5+1Hz (N=25) frequency at low intensity over each DLPFC and the brain stem for 7days were compared. Patients were followed for six months. UPDRS, the Trail Making Test, and dual tasks were applied. Patients ≤65years >65yrs were compared. Data were analyzed by repeated measure ANOVA. RESULTS: Only 1Hz had an effect on motor scores. Before the trial patients≤65 yrs had UPDRS total scores of 30.3±16.9, after 1 month: 17.8±8.9 p<0.001, after 6 months 18.3±8.8 p<0.001. Improvement of patients >65yrs was observed after one month (p<0.01). Executive function >65yrs (N=16) was significantly worse compared with C (N=15) and it was improved temporarily by 1Hz. Five Hertz and 5+1Hz did not cause improvement. CONCLUSION: One Hertz with proper intensity has a good outcome in PD. Patients >65yrs show deterioration in their executive function and they have shorter duration in their therapeutic effect of rTMS. This study draws attention to the importance of stimulation intensity and age as a predictor of the effect of rTMS.

Non-invasive brain stimulation (rTMS and tDCS) in patients with aphasia: mode of action at the cellular level.

A high proportion of patients who have suffered a stroke also suffer from aphasia. Approximately half of those affected will remain in this state despite intensive language therapy. Non-invasive brain stimulation allows us to directly and focally stimulate areas of the brain. Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), methods used in the treatment of aphasia, are based on an imbalance of mutual interhemispheric inhibition. In open and sham-controlled studies, a low-frequency, 1Hz stimulation of the non-lesioned hemisphere (the homologue of Broca's area) for a week or more significantly improved spontaneous speech and anomia in patients with non-fluent aphasia. These positive outcomes from rTMS stimulation developed slowly, often over months following treatment, and persisted. Effects of intermittent theta burst stimulation (iTBS) developed faster than the low-frequency stimulation, and high-activity enhancement was detected in the left hemisphere after the stimulation of Broca's region. Both types of tDCS stimulation resulted in improved comprehension and reduced anomia, their primary modes of action are distinct, however, both share a common site of action with regard to the balance that occurs between inhibitory and excitatory neurotransmitters (synaptic and non-synaptic). Both types of non-invasive stimulation prepare the lesioned brain for better outcome.

New advances in the rehabilitation of CNS diseases applying rTMS.

Transcranial magnetic stimulation (TMS) can directly stimulate the CNS, modifying the brain's plasticity to enhance the behavior of the paretic extremities. Studies with low-frequency repetitive TMS (rTMS) on the intact hemisphere and those with high frequencies on the affected hemisphere could increase the speed of movement in the hand affected by CNS injury. Stimulation of the motor pathway may contribute to faster improvement in patients with spinal cord injury. Symptoms of Parkinson's disease (such as cognition and working memory, neglect syndrome and global aphasia) can be influenced by rTMS. However, the site of stimulation and the parameters of rTMS are different. Processes that contribute to the behavior of rTMS include the modification of brain plasticity, induction of neurogenesis, growth of new fibers in the spinal cord or all of these together. According to previous research, rTMS may be suitable as an add-on therapy to rehabilitation in CNS diseases.