Background: The immune system declines in efficiency with advancing age, making the elderly less resistant to pathogenic microorganisms. Upper respiratory tract infection (URTI) is a common illness. Recent studies have shown that suppression of secretory immunoglobulin A (SIgA) is associated with increased incidence of URTI. Objective: To assess the effect of exercise on salivary SIgA in elderly subjects. Methods: Forty five elderly subjects (18 men, 27 women; mean (SD) age 64.9 (8.4) years) performed both 60 minute resistance and 60 minute moderate endurance training a week for 12 months. Saliva samples were obtained before training, and at four and 12 months during the training period. Salivary SIgA concentrations were measured by enzyme linked immunosorbent assay, and the SIgA secretion rate was calculated. Results: SIgA concentrations before training, and at four and 12 months during training were 24.7 (14.4), 27.2 (14.2), and 33.8 (18.5) µg/ml respectively. SIgA secretion rates were 29.5 (26.0), 33.8 (27.2) and 46.5 (35.1) µg/min respectively. The results indicate that both the concentration and secretion rate of SIgA significantly (p<0.01) increased during 12 months of exercise in these elderly subjects. Conclusion: Regular moderate exercise seems to enhance mucosal immune function in elderly subjects.

The vestibular nerves are known to influence neuronal circuits in the medullary cardiovascular areas and, through the cerebellar vermis, the basal ganglia and the limbic system. By means of noisy galvanic vestibular stimulation (GVS), it might be possible to ameliorate blunted responsiveness of degenerated neuronal circuits of patients with multi system atrophy or Parkinson's disease, or both. We evaluated the effect of 24-hour noisy GVS on long-term heart rate dynamics in 7 patients with multi system atrophy and on daytime trunk activity dynamics in 12 patients with either levodopa-responsive Parkinson's disease or levodopa-unresponsive parkinsonism. Six of the latter patients were also examined for cognitive performance by means of a continuous performance test. Short-range or high-frequency fluctuations of heart rate were significantly increased by the noisy GVS compared with sham stimulation, suggestive of improved autonomic, especially parasympathetic, responsiveness. Long-range antipersistency of trunk activity patterns probed by an autocorrelation measure was significantly increased by the noisy GVS, suggestive of quickening of bradykinesic rest-to-active transitions. The mean reaction time of the continuous performance test was also significantly decreased by the noisy GVS, without significant changes in either the omission or commission error ratios, which is suggestive of improved motor execution during the cognitive task. In conclusion, the noisy GVS is effective in boosting the neurodegenerative brains of patients with multi system atrophy or Parkinson's disease, or both, including those unresponsive to standard levodopa therapy; it is also effective in improving these patients' autonomic and motor responsiveness.

Through the cerebellar vermis, the vestibular nerves are known to influence the basal ganglia and the limbic system. By means of noisy galvanic vestibular stimulation (GVS), it may be possible to ameliorate movement disorders, particularly akinesic symptoms, in patients with central neurodegenerative disorders. We evaluated the effect of 24-hour noisy GVS on a power-law temporal autocorrelation exponent of daytime wrist activity, separately for higher (local maxima) and lower (local minima) levels of activity, in 14 hospitalized patients. The power-law exponent for the local maxima was significantly (p < 0.002) lower with the noisy GVS than with sham stimulation, suggestive of more frequent switching behavior from low to high levels of activity or less severe akinesia. The noisy GVS may thus potentially improve certain motor dysfunctions in patients with distinct central neurodegenerative diseases.