What influences stroke survivors with physical disabilities to be physically active? A qualitative study informed by the Theoretical Domains Framework

BACKGROUND

Although the benefits of regular physical activity (PA) after stroke are well established, many stroke survivors do not achieve recommended PA levels. To date, studies exploring determinants to PA have not used a behaviour change theory and focused on stroke survivors with physical disabilities. As a precursor to an intervention development study, we aimed to use the Theoretical Domains Framework (TDF) to identify factors influencing PA in stroke survivors with physical disabilities in Singapore.

METHODS

Between November 2021 and January 2022, we conducted interviews with 19 community-dwelling stroke survivors with a weak arm and/or leg. An interview guide based on the TDF was developed. We analysed the data deductively by coding interview transcripts into the theoretical domains of the TDF, and then inductively by generating themes and belief statements. To identify relevant TDF domains, we prioritised the domains based on the frequencies of the belief statements, presence of conflicting belief statements and evidence of strong belief statements.

RESULTS

Eight of the 14 TDF domains were relevant, and included environmental context and resources, knowledge, social influences, emotion, reinforcement, behavioural regulation, skills and beliefs about capabilities. The lack of access, suitable equipment and skilled help often limited PA participation at public fitness spaces such as parks, gyms and swimming pools (environmental context and resources). While a few stroke survivors expressed that they had the skills to engage in regular PA, most expressed not knowing how much and how hard to work, which exercises to do, which equipment to use and how to adapt exercises and equipment (knowledge and skills). This often left them feeling afraid to try new activities or venture out to new places for fear of the unknown or adverse events (e.g., falls) (emotion). For some, doing the activities in a group encourage them to get out and engage in PA (social influences).

CONCLUSIONS

In stroke survivors with physical disabilities, environmental context and resources had a significant influence on PA participation, and this often had a spill over effect into other domains. Our results inform a complex behaviour change intervention to improve PA after stroke, and has implications for intervention design for people with physical disabilities.

0519 Mindfulness Based Therapy for Insomnia Improves Objective Markers of Sleep in the Elderly: Preliminary Data from the Mindfulness Sleep Therapy (MIST) Study

Introduction

Mindfulness-based treatment for insomnia (MBTI) is a viable intervention for improving poor sleep. We report preliminary data from an ongoing pre-registered, randomized controlled trial which investigates the effect of MBTI on elderly adults.

Methods

Participants above 50 years old with PSQI ≥ 5 were recruited and randomised into either MBTI or an active control group (Sleep hygiene education and exercise program, SHEEP) in sequential cohorts with about 20 participants per cohort (10 per group). Before and after the intervention, 1 night of portable polysomnography (PSG) and 1 week of actigraphy (ACT) and sleep diary (DIARY) data were collected. We report the ACT and DIARY results of the first 3 cohorts (n = 46, male = 23, mean age = 62.3, std = 6.3) and PSG data of the first 2 cohorts (n = 29, male = 12, mean age = 62.5, std = 5.7). Time in bed (TIB), total sleep time (TST), sleep onset latency (SOL), wake after sleep onset (WASO), and sleep efficiency (SE) were analysed with mixed-model repeated-measures ANOVA.

Results

We observed increases in TIBDIARY (F1,44 = 5.151, p < .05) and SEDIARY (F1,44 = 22.633, p < .0001), and significant reductions in SOLDIARY (F1,44 = 7.031, p < .05) and WASODIARY (F1,39 = 7.411, p < .05). In the actigraphy data, we found a significant interaction in SOLACT (F1,39 = 4.273, p < .05) with an increase in SHEEP SOLACT (t18= 2.36, p < .05). Significant reductions were also observed in WASOACT (F1,44 = 16.459, p < .0001) Finally, we observed a reduction in SOLPSG (F1,26 = 5.037, p <. 05). All other tests were non-significant.

Conclusion

Preliminary results suggest that both interventions lead to improvements in sleep with more pronounced effects in subjective sleep reports. Objective sleep data suggest that improvements in sleep is a result of improved sleep quality and not simply extending sleep opportunity. These preliminary data shows that MBTI may be a promising intervention for elderly individuals with sleep difficulties.

Support

This study was supported by an award from the 7th grant call of the Singapore Millennium Foundation Research Grant Programme

0824 Improving Subjective Sleep Quality Measures Through Mindfulness Training in the Elderly: Preliminary Data from the Mindfulness Sleep Therapy (MIST) Study

Introduction

Poor sleep is a modifiable risk factor for multiple chronic disorders. Mindfulness-based therapies potentially improve sleep by enhancing awareness and acceptance of internal and external experiences, thus reducing pre-sleep hyper-arousal. In this pre-registered, randomized controlled trial, we tested the effect of mindfulness-based treatment for insomnia (MBTI) on subjective sleep quality measures (Pittsburgh Sleep Quality Questionnaire, PSQI) in the elderly.

Methods

Participants above 50 years old with sleep difficulties (PSQI ≥ 5) (mean (sd) age = 62.0 (6.35), 44 female) attended either an 8-week MBTI (N = 34) or sleep hygiene education and exercise program (SHEEP; N = 35). Before and after the interventions, we collected PSQI, insomnia symptoms and features measures (Pre-Sleep Arousal Scale, PSAS; Insomnia Severity Index, ISI; Dysfunctional Beliefs and Attitudes about Sleep, DBAS-30), mindfulness (Five-Facets Mindfulness Questionnaire, FFMQ), and mood and anxiety (Back Depression Inventory, BDI; State-Trait Anxiety Inventory, STAI). PSQI and PSAS (N = 26 to date) were collected at 6-month follow-up. Data were analysed with repeated-measures ANCOVA with group as a between-subject variable for the first 69 participants who completed the study.

Results

We observed significant improvement across both groups for sleep measures (PSQI: F1,67=36.442, p<.01; PSAS-Cognitive: F1,67=12.664, p<.01; ISI: F1,67=36.442, p<.0; DBAS: F1,67=28.749, p<.01) and mood (BDI: F1,67=26.393, p<.01; STAI-State: F1,67=4.608, p=.04; STAI-Trait: F1,67=7.687, p<.01), but not for Mindfulness (F1,67=2.256, p=.14) nor PSAS-somatic. No significant group by time interactions were found. We observed a correlation between PSQI decreases and FFMQ increases in MBTI (r=-.53, p<.01), but not in SHEEP (r=-.07, p=.70) participants. ANCOVA of 6-month PSQI data revealed a significant group by time interaction (F1,24=19.525, p=.03), with reduction from baseline in MBTI (t12=4.769, p<.01), but not in SHEEP group (t12=3.813, p=.08).

Conclusion

Preliminary results support MBTI as an accessible but effective behavioural intervention with potential long-term benefits for improving sleep and mood, and reducing cognitive-emotional arousal in the elderly.

Support

This study was supported by an award from the 7th grant call of the Singapore Millennium Foundation Research Grant Programme

Factor V is activated and cleaved by platelet calpain: comparison with thrombin proteolysis

Platelets are known to process human factor V during secretion and/or membrane binding. We studied the functional and structural changes produced in human factor V by purified human platelet calpain (calcium-activated thiol protease) and compared the alterations with those induced by thrombin. A maximum increase in coagulant activity of 2.5-fold was observed when factor V (1 U/mL, 33 nmol/L) was incubated with calpain (0.03 U/mL, 2.7 nmol/L) in comparison with a 8.8-fold increment for alpha-thrombin (0.7 U/mL, 8 nmol/L) at 25 degrees C. Thrombin additions to reactions initiated by calpain resulted in further activation comparable to that of thrombin alone, whereas the subsequent addition of calpain had no effect on the extent or pattern of the activation of factor V by thrombin. The cleavage pattern of factor V produced by these two enzymes are distinctly different. Although thrombin activation eventually results in four final components designated C1 (150 kd), D (105 kd), E (71 kd), and F1F2 (71 to 74 kd), calpain yields initial components of 200 kd and 160 kd within one minute. Further digestion of the 200 kd species by calpain gives rise first to a polypeptide of 160 kd that is converted to a 140 kd and a 120 kd species by two minutes with an increase in coagulant activity. Immunoblotting of these fragments with the monoclonal antibody (MoAb) B10 directed to factor V and the thrombin-generated C1 fragment yields results demonstrating a common epitope in these calpain-generated components of 200, 160, 140 and 120 kd. The degradation of the initial 160 kd polypeptide gives rise to polypeptides of 100 and 65 kd, both undetectable on immunoblotting with MoAb B10. The 130, 87, 58, and 48 kd components are of less certain origin. Thus, platelet calpain generates a complex but reproducible cleavage pattern different from thrombin that may explain the partial activation observed. Nevertheless, calpain processing may play a role in early hemostatic reactions involving platelets before the appearance of the first thrombin molecule.

Biology of human megakaryocyte factor V

To learn more about human megakaryocyte coagulation cofactor V (FV), we studied the expression of this protein in normal bone marrow megakaryocytes and in megakaryocytes cloned from their colony-forming unit in FV-depleted plasma clot cultures. Mouse monoclonal antibodies directed against either the light chain or an activation peptide of human FV and a rabbit polyclonal, monospecific FV antiserum were used as probes for these experiments in conjunction with a variety of immunochemical detection techniques. All morphologically recognizable megakaryocytes were shown to contain FV. The origin of this protein appeared to be both from FV bound to the cell as well as from endogenous FV in the majority of cells examined. The existence of a population of small bone marrow mononuclear cells that simultaneously expressed platelet glycoproteins and FV was also noted. Such cells represented approximately 70% of all small cells positive for platelet glycoproteins. In contrast, only about 40% of megakaryocyte colonies cloned in FV-deficient medium contained cells with immunochemically detectable FV. FV expression was most clearly demonstrated in large cells in the colonies, whereas smaller, presumably less mature cells labeled weakly or not at all. Synthesis of FV by human megakaryocytes was documented using elutriation-enriched cells incubated in 35S-methionine-containing medium. Megakaryocyte lysates and medium conditioned by these cells were subjected to immunoaffinity column purification. Column eluates analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography revealed radioactive bands comigrating with the heavy and light chains of thrombin-activated FV. These studies suggest that human megakaryocytes both bind and synthesize FV. Expression of these traits appears to be related to cell maturation, with binding ability appearing earlier than the ability to synthesize this protein. Finally, although the ability to bind FV appears to be universal among megakaryocytes, our culture data suggest that synthesis may be a restricted, or constitutively expressed property of these cells.

Expression of factor V on human umbilical vein endothelial cells is modulated by cell injury

Since human endothelial cells synthesize Factor V but do not secrete it into the medium, we studied the effects of cell injury on the availability of Factor V at the surface of these cells. Human umbilical vein endothelial cells (HUVEC), grown to confluency and incubated with human 125I Factor Va, specifically bound 5000 to 7000 molecules per cell. In the absence of added Va, no antigen was detected on adherent HUVEC with either labeled anti-V(Va) monoclonal or polyclonal IgG. However, exogenous Va, not V, prebound to these cells allows binding of labeled 125I anti-V(Va). Immunodectectibility of bovine Factor V contributed by fetal calf serum in the concentration used in cultures is less than 0.1% of that detected in human plasma. HUVEC, suspended by scraping from dishes, specifically bound 4000 molecules/cell of 125/I monoclonal IgG against V(Va). Although undisturbed cells excluded trypan blue, dye uptake by many of the suspended HUVEC indicated cell injury. Quantitation of injury by 51Cr release after scraping followed by multiple passages through an 18 g needle showed that 51Cr release increased with number of manipulations up to 60% and was observed almost immediately after manipulation. We suggest that little Factor V(Va) is present on the surface of intact adherent HUVEC. However, mechanical injury to HUVEC released or exposed endogenous Factor V(Va), resulting in expression of V that might mediate Factor Xa binding as well as activation of protein C by thrombin. Thus, injured, but not intact, HUVEC could participate in both promoting and limiting blood coagulation.

A comparative study of T-61 and pentobarbital for euthanasia of dogs

A comparative study of T-61 and double-strength pentobarbital for euthanasia of dogs was performed. Effects on EEG, ECG, arterial blood pressure, and respiration were monitored, and time to collapse was measured. In most respects, the effects of the 2 agents were similar; however, 3 of 12 dogs given pentobarbital resumed respiration and cardiac function. None of 9 dogs given T-61 evidenced signs of recovery.