Illusions of postural,visual, and aircraft motion elicited by deep knee bends in the increased gravitoinertial force phase of parabolic flight

Summary Illusions of self motion and aircraft motion are experienced when executing deep knee bends in the high force phases of parabolic flight. The occurrence of such illusions indicates that skeletomotor control is actively calibrated to a 1 g reference level and that departures from this level affect the execution and appreciation of voluntary movements. The origin of the illusory patterns is shown to be understandable in terms of mismatches between efferent control signals and expected patterns of associated muscle spindle activity. It is shown, too, that spindle activity is interpreted within an entire context of spatial information about ongoing and intended motion of the body and whether the body is laden.Supported by NASA contracts NAS9-15147 and T-9140E     

Effects of an environmental manipulation emphasizing client-centred care on agitation and sleep in dementia sufferers in a nursing home

This study was designed to determine whether a change from a task-oriented care approach to a client-oriented care approach affects (a) the level of agitation and (b) 24-hour sleep in residents suffering from dementia in a nursing home The levels of dementia and sleep of 33 nursing home residents were measured four times over 12 weeks (twice before and twice after the change in care approach) using the Cohen-Mansfield agitation inventory and the dementia mood assessment scale Verbal agitation levels significantly decreased 6 to 8 weeks following the change, whereas more infrequent agitated behaviours, which were classified as 'other', significantly increased Daytime sleep increased initially after the change but then returned to baseline levels after 6 weeks While the main focus of the study was on residents 'behaviour following an environmental manipulation, anecdotal observations of staff members interactions with residents indicated that they felt less rushed and were more tolerant of residents' behaviour following the intervention     

Comparing outcomes in renal replacement therapy: how should we correct for case mix?

The need to evaluate the effectiveness of clinical practice to justify expensive therapy in the face of financial constraints in all areas of health care delivery makes it necessary to identify groups of patients who are likely to benefit most from treatment. Various risk stratification methods have been used for analyzing survival probabilities for patients receiving renal replacement therapy. Complicated risk stratification methods produce large numbers of risk groups of small sizes, which makes comparison between individual centers difficult. We compared three simple methods of risk stratification, that divided patients into low-, medium-, and high-risk groups, in a cohort of 1,407 patients who commenced renal replacement therapy in five European countries during a 7-year period. Method 1 considered age (>55 years) and diabetes alone; method 2 used a higher age limit (>70 years) and comorbid illnesses, including those other than diabetes; and method 3 used only the number of comorbidities (none, 1, or > or =2) for stratification. Kaplan-Meier survival curves were constructed for comparison between risk groups and Cox's regression model used to assess strength of relationship with mortality. Although patient survival was significantly different between the low-, medium-, and high-risk groups using all three methods, Cox's regression analysis showed that method 2 provided the greatest discrimination between risk groups. In predicting mortality, method 2 (based on comorbidities and age) showed the highest sensitivity and specificity (84% and 80%, respectively) compared with method 1 (80% and 74%) and method 3 (64% and 82%). Validation of this approach in other populations in a prospective study is required before this method, which takes into account the influences of both age and comorbidity for risk stratification, can be used for comparing survival data and for presenting results of renal replacement therapy.     

Evaluation of a tactile hardness test in indirect pulp capping

Summary. The value of a tactile hardness test in indirect pulp capping was investigated by comparing hardness values with the biochemical analysis for phosphorus. Statistically significant differences were found between the 6-month evaluation groups recorded as soft or medium and those recorded as hard. However, there were no differences between groups evaluated as soft or medium before or after treatment.     

Meta-analysis of blood pressure tracking from childhood to adulthood and implications for the design of intervention trials

Aim:  Blood pressure (BP) is related with cardiovascular disease. BP tracking in childhood and its implication for intervention trials are unknown.
Methods:  A systematic review and meta-analysis were conducted to estimate BP tracking.
Results:  In 29 independent studies on 27 820 subjects, follow-up length and baseline age were associated with systolic BP tracking (both p < 0.05), while gender, BP measurement method and study place were not (p = 0.215, p = 0.185 and p = 0.391). The overall adjusted systolic BP correlation coefficient was 0.44 between 10 and 11 years and decreased to 0.37 between 10 and 20 years. Comparison of BP changes before and after intervention need a 26% increased sample size for a 10-year follow-up of 10 year olds, while trials comparing BP values at study end only require smaller sample sizes.
Conclusion:  Blood pressure tracking from childhood to adulthood affects trials assessing long-term effects on BP and was low-to-moderate. Therefore, regular BP controls are also needed in children with normal BP measurements possibly identifying hypertensive children earlier. A slight short-term intervention effect on BP may not have any long-term effects because of low BP tracking and its decrease by age.     

Neural representation of time in cortico-basal ganglia circuits

Encoding time is universally required for learning and structuring motor and cognitive actions, but how the brain keeps track of time is still not understood. We searched for time representations in cortico-basal ganglia circuits by recording from thousands of neurons in the prefrontal cortex and striatum of macaque monkeys performing a routine visuomotor task. We found that a subset of neurons exhibited time-stamp encoding strikingly similar to that required by models of reinforcement-based learning: They responded with spike activity peaks that were distributed at different time delays after single task events. Moreover, the temporal evolution of the population activity allowed robust decoding of task time by perceptron models. We suggest that time information can emerge as a byproduct of event coding in cortico-basal ganglia circuits and can serve as a critical infrastructure for behavioral learning and performance.