[Microsurgical treatment of aneurysms of vertebral and posterior-lower cerebellar arteries: surgical approaches, exclusion options, treatment results]. / Mikrokhirurgicheskoe lechenie anevrizm pozvonochnykh i zadnikh nizhnikh mozzhechkovykh arterii: khirurgicheskie dostupy, varianty vykliucheniia, rezul'taty lecheniia.

Aneurysms of vertebral (VA) and posterior inferior cerebellar arteries (PICA) are relatively rare pathologies and account for 3.4% of the total number of intracranial aneurysms. MATERIAL AND METHODS: The experience of microsurgical treatment of 67 patients with VA and PICA aneurysms in N.N. Burdenko National Medical Research Center for Neurosurgery of the RF Ministry of Health from 2012 to 2017 is presented. RESULTS: Most patients underwent reconstructive microsurgical interventions: clipping of the aneurysm neck in 42 (62.7%) patients and complex clipping with the formation of arterial opening - in 10 (14.9%). Exclusion of the aneurysm together with the carrier artery (trapping, proximal clipping) was performed on 10 (14.9%) patients. In 5 (7.5%) patients, deconstruction of the carrier artery of the aneurysm was performed after creating local anastomoses. The radical exclusion of aneurysms in the studied group was 95.5%. Postoperative dysfunction of the caudal group of cranial nerves was detected in 11 (16.4%) patients. There were no lethal outcomes, or cases with vegetative status outcomes. CONCLUSION: Microsurgical intervention is an effective way to treat VA and PICA aneurysms, subject to the principles of patient selection based on existing treatment algorithms as well as adherence to an interdisciplinary approach.

[Individual preoperative 3D modeling of vascular brain pathology]. / Individual'noe predoperatsionnoe 3D-modelirovanie sosudistoi patologii golovnogo mozga.

The possibility of segmenting three-dimensional objects by DICOM-series is well known and available both on specialized workstations and on personal computers. The technique, however, is relatively rarely used in clinical practice, and we believe that the benefits of preoperative preparation using segmented 3D models are underestimated. The article is devoted to our experience in using segmentation of anatomical structures based on CT and MRI for preoperative preparation for surgical operations performed in neurosurgical departments on patients with vascular pathology. The paper discusses the types and possibilities of segmentation, provides some examples describing the clinical use of the technique.

Useful field of view as a reliable screening measure of driving performance in people with Parkinson's disease: results of a pilot study.

PURPOSE: To determine the correlations of the Useful Field of View (UFOV), compared to other clinical tests of Parkinson's disease (PD); vision; and cognition with measures of on-road driving assessments and to quantify the UFOV's ability to indicate passing/failing an on-road test in people with PD. METHODS: Nineteen randomly selected people with idiopathic PD, mean age = 74.8 (6.1), 14 (73.7%) men, 18 (94.7%) Caucasians, were age-matched to 104 controls without PD. The controls had a mean age of 75.4 (6.4), 59 (56.7%) men, 96 (92.3%) Caucasians. Both groups were referred for a driving evaluation after institutional review board approval. RESULTS: Compared to neuropsychological and clinical tests of vision and cognition, the UFOV showed the strongest correlations (r > .75, p < 0.05) with measures of failing a standardized road test and number of driving errors. Among PD patients, the UFOV Risk Index score of 3 (range 1-5) was established as the optimal cutoff value for passing the on-road test, with sensitivity 87 percent and specificity 82 percent, AUC = 92 percent (SE 0.61, p = .002). Similarly, the UFOV 2 (divided attention) optimum cutoff value is 223 ms (range 16-500 ms), sensitivity 87.5 percent, specificity 81.8 percent, AUC = 91 percent (SE 0.73, p = .003). The UFOV 3 (selected attention) optimal cutoff value is 273 ms (range 16-500 ms), sensitivity 75 percent, specificity 72.7 percent, AUC = 87 percent (SE 0.81, p = .007). CONCLUSION: In this pilot study among PD patients, the UFOV may be a superior screening measure (compared to other measures of disease, cognition, and vision) for predicting on-road driving performance but its rigor must be verified in a larger sample of people with PD.

Reliability of motor cortex transcranial magnetic stimulation in four muscle representations.

OBJECTIVE: Motor cortex plasticity may underlie motor recovery after stroke. Numerous studies have used transcranial magnetic stimulation (TMS) to investigate motor system plasticity. However, research on the reliability of TMS measures of motor cortex organization and excitability is limited. We sought to test the reliability of these TMS measurements. METHODS: Twenty healthy volunteers were tested twice over a two-week period using TMS to determine motor threshold, map topography, and stimulus-response curves for first dorsal interosseous (FDI), abductor pollicis brevis (APB), extensor digitorum communis (EDC), and flexor carpi radialis (FCR) muscles. RESULTS: We found moderate to good test-retest reliability TMS measurements of motor threshold (ICC=0.90-0.97), map area (ICC=0.63-0.86) and location (ICC=0.69-0.86), and stimulus-response curves (ICC=0.60-0.83). CONCLUSIONS: TMS assessments of motor representation size, location, and excitability are generally reliable measures, although their reliability may vary according to the muscle under investigation. SIGNIFICANCE: These results suggest that TMS measurements of motor cortex function are reliable enough to be potentially useful in investigation of motor system plasticity.

Using the BTE Primus to measure grip and wrist flexion strength in physically active wheelchair users: an exploratory study.

OBJECTIVE: The purpose of this study was to establish test-retest reliability values for the newly designed grip and wrist attachments of the BTE Primus and to determine criterion-related validity of the new grip attachment against the Jamar dynamometer. An additional purpose was to explore the differences in grip and wrist flexion strength between wheelchair users and control participants without disabilities and to examine the effect of body position on strength in persons without disabilities. METHOD: Wheelchair users and matched controls (13 per group) were tested for grip and wrist flexion strength on the BTE Primus and for grip on the Jamar dynamometer. RESULTS: The BTE Primus grip attachment was found to be valid and reliable. No significant differences were found in static and dynamic grip or wrist flexion strength between the two groups or in the sitting versus standing position for the control group. CONCLUSION: The findings suggest that the BTE Primus may be used to assess grip and wrist flexion strength validly and reliably for both wheelchair users and persons without disabilities.

The coefficient of variation as a measure of sincerity of effort of grip strength, Part I: the statistical principle.

The coefficient of variation (CV) is a widely used measure of sincerity of effort of grip strength despite contradictory research findings and lack of empirical support in the literature. The purpose of this study was to investigate whether the CV is an appropriate measure of sincerity of effort. One hundred forty-six uninjured volunteers underwent a series of grip strength tests. The mean, standard deviation (SD), and CV of repeated strength trials were calculated, and paired comparisons were conducted between maximal and submaximal efforts. While the mean of maximal trials was significantly greater, there were no differences in SD between maximal and submaximal trials. Therefore, the increased CV associated with submaximal effort was an artifact of reduced torque rather than an indicator of a true increase in variability. Consequently, the CV is not an appropriate measure of sincerity of effort of grip strength.

The coefficient of variation as a measure of sincerity of effort of grip strength, Part II: sensitivity and specificity.

The coefficient of variation (CV) is commonly used to detect sincerity of effort. The purpose of this study was to examine whether the CV possessed adequate sensitivity and specificity to effectively detect sincerity of effort of grip strength. One hundred forty-six uninjured volunteers underwent a series of grip strength tests. Sensitivity and specificity values were calculated for various CV cut-off values (between 2.5% and 22%) of the static grip test. The receiver operating characteristic (ROC) curves based on these values demonstrated the trade-offs between specificity and sensitivity. For example, the "traditional" 15% cut-off value yielded poor sensitivity (0.55), whereas the 11% cut-off value yielded poor specificity (0.74). Selecting any cut-off value along the continuum did not provide adequate sensitivity or specificity for labeling an effort sincere or insincere. Although the CV differentiated between maximal and submaximal effort, it was not sensitive or specific enough to do so effectively. Thus, the CV should not be used to assess sincerity of effort of grip strength.

The use of the rapid exchange grip test in detecting sincerity of effort, Part I: administration of the test.

A review of studies that utilize the rapid exchange grip (REG) test revealed that there is no standardized test protocol for administering the test. The purpose of this study was to investigate three factors that affect the result of the REG test: the hand switch rate, the number of grips performed during the test, and the comparative tests used in the interpretation of the REG test. The 146 uninjured subjects performed a series of randomized grip strength tests including the REG test, the maximal static grip test (MSGT), and the five-rung (5R) test while making maximal and submaximal efforts. Results revealed no significant differences in peak REG scores between hand switch rates of 45 and 60 rpm. Significant differences were found for peak REG scores obtained from three vs. five trials. Peak scores from the 5R test vs. the MSGT differed significantly for maximal efforts but not for submaximal efforts. These results led to the following recommendations for a standardized protocol for administering the REG test: 1) the REG maneuver may be administered at a rate of either 45 or 60 rpm; 2) at least five hand-grip exchanges must be performed; and 3) only one comparative test, either the MSGT or the 5R test, should be used consistently for comparison with the REG maneuver. The findings of the present study, however, did not verify which static grip test should be used for comparison with REG scores.

The use of the rapid exchange grip test in detecting sincerity of effort, Part II: validity of the test.

The rapid exchange grip (REG) test was developed to identify patients exerting insincere effort. The premise of the REG test is that a maximal, sincere effort yields a "negative REG," in which peak static grip (SG) scores are greater than peak REG scores, and that a submaximal, insincere effort yields a "positive REG," in which REG scores are greater than SG scores. There is disagreement in the literature concerning what constitutes a positive REG test, suggesting that the REG may not be a valid measure of sincerity of effort. The purpose of the present study was to investigate the validity of the REG test by examining its premise as well as its sensitivity and specificity values. The 146 uninjured subjects performed a series of randomized grip strength tests, exerting both maximal and submaximal efforts. The tests included the REG at hand switch rates of 45 rpm (REG-45) and 60 rpm (REG-60), the maximal static grip test (MSGT), and the five-rung test (5R). Our findings supported the concept of a "negative REG" for both REG maneuvers and both comparative SG tests. The concept of a "positive REG," however, was supported only when peak REG scores were compared with peak 5R scores. The authors found relatively low sensitivity and specificity values, suggesting that the REG test may not be sensitive or specific enough to effectively detect sincerity of effort. The authors discuss the likelihood that mistakes will be made when the REG test is used to diagnose sincerity of effort and the possible consequences of making such mistakes.

Using the coefficient of variation to detect sincerity of effort of grip strength: a literature review.

Many clinicians use the coefficient of variation (CV) to assess sincerity of effort, without understanding the premise on which it is based or its physiological and mathematical bases. Clinicians who use computerized evaluation systems that calculate the CV may not even be aware of the formula used to derive it. The wide use of the CV in detecting sincerity of effort of grip strength is puzzling, since it lacks empirical support in the literature. This paper examines the physiological rationale for using measures of variability to detect sincerity of effort, the mathematical basis on which the CV is founded, and the reliability and validity of the CV. The conclusions based on this literature review are that the CV is not an appropriate method for determining whether an effort is sincere and that CV values may be inflated in injured patients with compromised hand strength.

A pilot study: attitudes toward leisure and leisure motivation in adults with spinal cord injury.

This pilot study explored the effect that an introduction to wheelchair sports would exert on attitudes and motivation toward leisure in a sample of adults with spinal cord injury. Individuals were tested using the Leisure Attitude Measurement (LAM) and the Leisure Motivation Scale (LMS) both before and after participating in a wheelchair sports program. Camp participants were demographically matched with a control group of persons who did not participate in a sports camp during the testing sessions. No significance was detected in within-group comparisons but high effect size and power on subscales of the LMS suggest a need for further studies. The experimental group, however, had significantly lower scores in stimulus avoidance as a leisure motivator which emphasizes the importance of social interaction in sports participation.

Increased tail artery vascular responsiveness to angiotensin II in cold-treated rats.

Chronic exposure of rats to cold for 1-3 weeks results in a mild form of hypertension. The renin-angiotensin system (RAS) has been implicated in this model of cold-induced hypertension. Previously we have characterized the vascular responsiveness in cold-acclimated animals, using aortic tissue, and recent studies have focused on the thermoregulatory responses of angiotensin II (AngII), utilizing the tail artery of the rat. Therefore in the current study we evaluated the vascular responsiveness of cold-treated rats to AngII in both aorta and tail artery at 2 and 4 weeks of cold exposure (5+/-2 degrees C). Systolic blood pressures were significantly elevated in cold-treated animals compared with control animals at both 2 and 4 weeks of cold exposure. At both of these time points body weights were reduced and ventricular weights were increased in cold-treated animals. After 2 weeks of cold exposure the vascular responsiveness of the aorta to AngII was significantly lower than that of controls. This vascular responsiveness to AngII was elevated and returned to control levels after 5 weeks of cold exposure. However, this pattern was not observed in the tail artery. The vascular responsiveness of tail artery rings from cold-treated rats to AngII was significantly greater than that of control animals during both 2 and 5 weeks of exposure to cold. The vascular contractile responses of both the aorta and tail artery to KCI in the cold-treated animals was not different from that of the control animals maintained at ambient room temperature, suggesting that the vascular smooth muscle contractile components were not altered by the cold exposure. Thus, the in vitro vascular reactivity to the receptor-mediated vasoconstrictor AngII was decreased in the sparsely innervated aorta and increased in the more densely innervated tail artery of the cold-treated animals when compared with controls. These results suggest that the increased responsiveness of AngII on the smooth muscle of the tail artery may play a role in adaptation to the cold and the maintenance of cold-induced hypertension.

Occupational therapy: current practice and training issues in the treatment of cognitive dysfunction.

A significant relationship exists between cognitive abilities and functional performance in activities of daily living. Occupational therapists are involved in providing cognitive rehabilitation to individuals with brain damage by assisting them in fulfilling self-care, work and leisure roles. Since occupational therapists specialize in functioning in the real world, they should have a primary role on the interdisciplinary team in assessing and treating cognition as it relates to function. Particular areas of expertise include assessment and intervention in daily living tasks, safety issues and cognitive/perceptual dysfunction. Treatment strategies in occupational therapy are classified into two approaches: remedial and compensatory. A combination of the two approaches has been found to be the most beneficial method of intervention. Though current training guidelines for occupational therapists in cognitive rehabilitation are vague, the major focus has been on evaluating functional status and intervening when cognitive/perceptual deficits are present. Future training for practitioners in this area will require more specialized experiences and education. Additional research will need to be conducted by therapists to document treatment efficacy. Despite current health care constraints, occupational therapists must not lose sight of delivering quality care in an individualized and holistic manner.

The effect of exercise training on cold tolerance in adult and old C57BL/6J mice.

In order to ascertain the effect of aging on cross-adaptation between exercise training and cold tolerance, we studied cold tolerance in adult and old C57BL/6J male mice before and after 6 weeks of an exercise regimen of moderate intensity. There were two age groups of 32 mice each, including 12-month-old (adult) and 24-month-old (aged) mice equally divided into control and exercise groups. The exercise consisted of daily runs on a treadmill (1 hr/day, 5 days/week) for 6 weeks, while the control mice spent the same time on a stationary treadmill. All mice were subjected to a cold stress test (3-hr partial restraint at 6 degrees C) prior to and following the designated regimen. The results revealed a statistically significant interaction between age and exercise training. In adult mice, exercise resulted in a reduction of cold-induced heat production and weakening of cold tolerance, while in aged mice, the opposite effect was observed; i.e., an increase in cold-induced heat production accompanied by greater cold tolerance. However, only the attenuating effect on cold tolerance of adults was statistically significant. The results of our experiments do not support the existence of cross-adaptation between exercise training and cold tolerance. They indicate, however, that exercise training affects the cold tolerance in adult and old mice through different physiological mechanisms.

Increased dipsogenic responsiveness to angiotensin II in rats exposed to cold: rate of loss after return to thermoneutral ambient temperature.

Subcutaneous administration of angiotensin II (Ang II) to rats exposed chronically to 5 degrees C induced an increased drinking response compared with that of warm-acclimated controls. The exaggerated drinking response was also observed when graded doses of Ang II were administered into the lateral cerebroventricle (icv) of chronically cold-exposed rats. A maximal drinking response occurred in cold-treated, but not in control, rats when the lowest dose of Ang II (1.6 ng/rat) was administered icv. Thus, it is clear that the dipsogenic responsiveness to either centrally or peripherally administered Ang II is increased by chronic exposure to cold. To assess whether the increased responsiveness was retained after removal from cold, graded doses of Ang II were administered to rats removed from cold to a thermoneutral environment. The results again showed a maximal responsiveness to the lowest dose of Ang II administered (25 micrograms/kg, sc) to cold-treated rats that had either just been removed from cold or removed from cold 2 hr prior to treatment. Cold-exposed rats had an ED50 for Ang II-induced drinking that was about half that of their warm-acclimated controls. To assess how long the cold-induced increase in dipsogenic responsiveness to Ang II lasted after return to a thermoneutral temperature, rats were removed from cold for 24, 48, or 60 hr and then administered graded doses of Ang II (25, 50, or 100 micrograms/kg, sc). The results suggest that between 46 and 52 hr after removal from cold, the cold-induced increase in dipsogenic responsiveness to Ang II returned to the level of the controls. Hence, the physiological changes in the dipsogenic mechanism induced by exposure to cold are not immediately reversible when the rats are returned to a thermoneutral ambient temperature.

Effect of exercise on cold tolerance and metabolic heat production in adult and aged C57BL/6J mice.

Two groups of adult (12-mo-old) and two groups of aged (24-mo-old) C57BL/6J male mice were subjected to a standardized cold stress test (3-h partial restraint at 6 degrees C). One group from each age group was tested in the morning, and the other was tested in the afternoon. Half of the mice were subjected to running exercise on a treadmill during 1 h before the cold stress test. The other half were placed on a nonoperational treadmill for 1 h before the cold stress test. One hour of exercise resulted in improvement of cold tolerance during the subsequent cold exposure in both age groups but only during afternoon testing. Improvement in cold tolerance was not accompanied by an elevation of cold-induced metabolic heat production in adult mice. Metabolic heat production in aged mice showed only modest elevation. The discrepancy between improvement in cold tolerance and lack of elevation of metabolic heat production suggests that the primary mechanism for augmentation of cold tolerance after exercise in the afternoon is an improvement in cold-induced vasoconstriction of skin vessels, which is probably normally compromised in the afternoon.

The effect of intermittent exposure to cold on the development of hypertension in the rat.

Continuous exposure to a cold (5 degrees C) environment has been shown to induce hypertension in rats. The total time required for the first significant elevation of blood pressure is dependent on a number of factors, including the ambient temperature and the weight of the rat at the time of exposure to cold. The present study was also concerned with the minimal time of daily exposure to cold that would result in a significant elevation of blood pressure. To achieve this, we used four groups of rats. One was exposed to cold for 4 h daily (09:00 to 13:00), a second group was exposed to cold for 8 h daily (09:00 to 17:00), and a third was exposed for 24 h daily. The fourth group remained at 25 degrees C. Systolic blood pressures of the group exposed to continuous cold became elevated significantly above pre-cold exposure level within 2 weeks of cold exposure. Blood pressures of the groups exposed to cold for 4 and 8 h daily became elevated significantly above the level of the warm-adapted control group by day 27 of exposure to cold, but failed to reach the level of the chronically cold-exposed group even after 42 days of exposure to cold. There was a sigmoid-type relationship between the hours per day exposed to cold and systolic blood pressure at the end of the experiment. Thus, graded elevations of systolic blood pressure occur with increasing daily duration of exposure to cold.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevention of cold-induced increase in blood pressure of rats by captopril.

To assess the possibility that the renin-angiotensin system may play a role in the development of cold-induced hypertension, three groups of rats were used. Two groups were exposed to cold (5 +/- 2 degrees C) while the remaining group was kept at 26 +/- 2 degrees C. One group of cold-treated rats received food into which captopril (0.06% by weight) had been thoroughly mixed. The remaining two groups received the same food but without captopril. Systolic blood pressure of the untreated, cold-exposed group increased significantly above that of the warm-adapted, control group within 4 weeks of exposure to cold. In contrast, chronic treatment with captopril prevented the elevation of blood pressure. Rats were killed after 4 months of exposure to cold. At death, the heart, kidneys, adrenal glands, and interscapular brown fat pad were removed and weighed. Although captopril prevented the elevation of blood pressure in cold-treated rats, it did not prevent hypertrophy of the kidneys, heart, and interstitial brown adipose tissue that characteristically accompanies exposure to cold. Thus, chronic treatment with captopril prevented the elevation of blood pressure when administered at the time exposure to cold was initiated. It also reduced the elevated blood pressure of cold-treated rats when administered after blood pressure became elevated. This suggests that the renin-angiotensin system may play a role in the elevation of blood pressure during exposure to cold.

Changes in blood pressure and dipsogenic responsiveness to angiotensin II during chronic exposure of rats to cold.

Hypertension accompanies chronic exposure of rats to cold (5-6 degrees C). Systolic, diastolic, and mean blood pressures become elevated, and hypertrophy of the heart occurs. A previous study from this laboratory suggested that the renin-angiotensin system may play a role. The present study was carried out to assess this further. Thus, in addition to measurement of systolic blood pressure at intervals during exposure to cold, plasma renin activity and the dipsogenic responsiveness to acute administration of angiotensin II were also measured to assess the functional status of the renin-angiotensin system. The results showed a significant (p less than 0.05) increase in systolic blood pressure during the third week of exposure to cold. In contrast, plasma renin activity (PRA) increased within the first week of exposure to cold, and declined thereafter to reach the level of the control by the third week of exposure to cold. By the fourth week, PRA decreased to a level significantly (p less than 0.05) below that of the control group. The responsiveness to acute administration of angiotensin II (AII), as assessed by the drinking response, increased significantly (p less than 0.05) by the third week of exposure to cold and remained significantly elevated during the fourth week. There was a significant (p less than 0.01) direct relationship between dipsogenic responsiveness to AII and blood pressure in the cold-treated (r = .57), but not the control group (r = .12). There was also a significant (r = -.91) indirect linear relationship between PRA and dipsogenic responsiveness to AII. Cold-treated rats had significant increases in urinary norepinephrine output and weights of heart, kidneys, adrenals, and brown adipose tissue characteristic of rats acclimated to cold.(ABSTRACT TRUNCATED AT 250 WORDS)

Factors affecting cold-induced hypertension in rats.

A 3- to 4-week exposure of rats to a cold environment (5 +/- 2 degrees C) induces hypertension, including elevation of systolic, diastolic, and mean blood pressures and cardiac (left ventricular) hypertrophy. The studies described here were designed to investigate some factors affecting both the magnitude and the time course for development of cold-induced hypertension. The objective of the first study was to determine whether there was an ambient temperature at which the cold-induced elevation of blood pressure did not occur. The objective of the second experiment was to determine whether body weight at the time of exposure to cold affected the magnitude and time course for development of hypertension. To assess the first objective, male rats were housed in a chamber whose temperature was maintained at 5 +/- 2 degrees C while others were housed in an identical chamber at 9 +/- 2 degrees C. After 7 days of exposure to cold, the rats exposed to the colder temperature had a significant elevation of blood pressure (140 +/- 2 mm Hg) compared with the group maintained at 9 degrees C (122 +/- 3 mm Hg). The rats exposed to 9 degrees C had no significant elevation of systolic blood pressure at either 27 or 40 days after initiation of exposure to cold. At the latter time, the temperature in the second chamber was reduced to 5 +/- 2 degrees C. By the 25th day of exposure to this ambient temperature, the rats had a significant increase in systolic blood pressure above their levels at 9 degrees C. Thus, there appears to be a threshold ambient temperature for elevation of blood pressure during exposure to cold. That temperature appears to lie somewhere between 5 and 9 degrees C. The second objective was assessed by placing rats varying in weight from approximately 250 to 430 g in air at 5 degrees C. There was a highly significant direct relationship (r = 0.96) between body weight at the time of introduction to cold and the number of days required to increase systolic blood pressure by 10 mm Hg above pre-cold exposure level. The third objective was to make an initial assessment of potential differences among strains of rats with respect to development of cold-induced hypertension. To this end, rats of the Fischer 344 strain were used. Systolic blood pressures of these rats also increased during chronic exposure to cold.(ABSTRACT TRUNCATED AT 400 WORDS)