Systolic Blood Pressure Threshold for HEMS-Witnessed Arrests.

OBJECTIVE: Defining vital sign thresholds has focused on mortality, which may be delayed for hours, days, or weeks after injury. This limits the immediate clinical significance in guiding therapy to avoid arrest. The aim of this study was to identify a systolic blood pressure (SBP) threshold indicating imminent cardiopulmonary arrest. METHODS: This was a retrospective, observational study analyzing physiological data from air medical patients suffering witnessed arrest. We limited the analysis to a subgroup of adult (> 14 years) patients with hypoperfusion-related arrest. Prearrest SBP values were plotted over time, with arrest defined as "time zero." Multiple linear regression was used to define a best fit curve to identify an inflection point beyond which arrest was imminent. RESULTS: A total of 53 eligible patients were identified; 33 (62%) were trauma victims. A fifth-degree equation showed appropriate goodness of fit (r = -.66, P < .0001). An inflection point was identified at an SBP of 78 mm Hg, with arrest occurring approximately 3 minutes later. CONCLUSION: An inflection point below SBP 80 mm Hg was identified, suggesting a predictable physiological pattern for perfusion-related deterioration. This may help guide therapy to reverse deterioration and prevent arrest.

Lifespan trajectory of myelin integrity and maximum motor speed.

OBJECTIVE: Myelination of the human brain results in roughly quadratic trajectories of myelin content and integrity, reaching a maximum in mid-life and then declining in older age. This trajectory is most evident in vulnerable later myelinating association regions such as frontal lobes and may be the biological substrate for similar trajectories of cognitive processing speed. Speed of movement, such as maximal finger tapping speed (FTS), requires high-frequency action potential (AP) bursts and is associated with myelin integrity. We tested the hypothesis that the age-related trajectory of FTS is related to brain myelin integrity. METHODS: A sensitive in vivo MRI biomarker of myelin integrity (calculated transverse relaxation rates (R(2))) of frontal lobe white matter (FLwm) was measured in a sample of very healthy males (N=72) between 23 and 80 years of age. To assess specificity, R(2) of a contrasting early-myelinating region (splenium of the corpus callosum) was also measured. RESULTS: FLwm R(2) and FTS measures were significantly correlated (r=.45, p<.0001) with no association noted in the early-myelinating region (splenium). Both FLwm R(2) and FTS had significantly quadratic lifespan trajectories that were virtually indistinguishable and both reached a peak at 39 years of age and declined with an accelerating trajectory thereafter. CONCLUSIONS: The results suggest that in this very healthy male sample, maximum motor speed requiring high-frequency AP burst may depend on brain myelin integrity. To the extent that the FLwm changes assessed by R(2) contribute to an age-related reduction in AP burst frequency, it is possible that other brain functions dependent on AP bursts may also be affected. Non-invasive measures of myelin integrity together with testing of basic measures of processing speed may aid in developing and targeting anti-aging treatments to mitigate age-related functional declines.

Cognitive stimulation intervention for elders with mild cognitive impairment compared with normal aged subjects: preliminary results.

BACKGROUND AND AIMS: Cognitive training programs have been developed for Alzheimer's disease patients and the healthy elderly population. Collective cognitive stimulation programs have been shown to be efficient for subjects with memory complaint. The aim of this study was to evaluate the benefit of such cognitive programs in populations with Mild Cognitive Impairment (MCI). METHODS: Twelve patients with MCI and twelve cognitively normal elders were administered a cognitive stimulation program. Cognitive performance (Logical Memory, Word paired associative learning task, Trail Making Test, verbal fluency test) were collected before and after the intervention. A gain score [(post-score - pre-score)/ pre-score] was calculated for each variable and compared between groups. RESULTS: The analysis revealed a larger intervention size effect in MCI than in normal elders' performances on the associative learning task (immediate recall: p<0.05, delayed recall: p<0.01). The intervention was more beneficial in improving associative memory abilities in MCI than in normal subjects. At the end of the intervention, the MCI group had lower results than the normal group only for the delayed recall of Logical Memory. CONCLUSIONS: Although further studies are needed for more details on the impact of cognitive stimulation programs on MCI patients, this intervention is effective in compensating associative memory difficulties of these patients. Among non-pharmacological interventions, cognitive stimulation therapy is a repeatable and inexpensive collective method that can easily be provided to various populations with the aim of slowing down the rate of decline in elderly persons with cognitive impairment.