Dynamic balance assessment during gait in spinal pathologies – A literature review

AbstractThe role of the spine as a gait stabilizer is essential. Dynamic assessment, while walking, might provide complementary data to improve spinal deformity management. The aim of this paper was to review spine dynamic behavior and the various methods that have been used to assess gait dynamic balance in order to explore the consequences of spinal deformities while walking. A review was performed by obtaining publications from five electronic databases. All papers reporting pathological or non-pathological spine dynamic behavior during gait and dynamic balance assessment methods were included. Sixty articles were selected. Results varied widely according to pathologies, study conditions, and balance assessment techniques. Three methods assessing dynamic stability during gait were identified: local-orbital dynamic stability, tri-axial accelerometry, and dynamic stability margin. Data from conventional gait analysis techniques were established essentially for scoliosis and low back pain, but they do not assess specific consequences on gait dynamic balance. Three techniques investigate gait dynamic balance and have been validated in normal subjects. Further investigations need to be performed for validation in spinal pathologies as well as the value for clinical practice.Level of evidenceLevel IV

Associations between neighborhood park space and cognition in older adults vary by US location: The Multi-Ethnic Study of Atherosclerosis

We used cross-sectional Multi-Ethnic Study of Atherosclerosis data from six US cities/counties and adjusted multilevel linear regression to examine park space-cognition associations among non-demented older adults (n = 4084). We found that greater neighborhood park space 1-mile around the residence (measured continuously) was associated with better processing speed in the overall sample (estimate: 0.48; 95% CI: 0.03, 0.92). However, greater neighborhood park space (½-mile around residence) was associated with worse global cognition in Los Angeles, California (estimate: -2.66; 95% CI: -4.70, −0.62) and worse processing speed in Forsyth County, North Carolina (estimate: -0.72; 95% CI: -1.37, −0.08). Dichotomizing at the mean, having ≥6% park space (½-mile around residence) was associated with better global cognition in Saint Paul, Minnesota (estimate: 0.21; 95% CI: 0.05, 0.38), and better processing speed in New York City (estimate: 0.19; 95% CI: 0.04, 0.35). Park space-cognition associations varied by city/county, suggesting problems with pooling multiple sites without accounting for geographic context or regionally-varying park characteristics (e.g., quality)

Psychological stress and other potential triggers for recurrences of herpes simplex virus eye infections

Objective To assess psychological stress and other factors as possible triggers of ocular herpes simplex virus (HSV) recurrences. Design A prospective cohort study nested in a randomized, placebo-controlled, clinical trial. Setting Fifty-eight community-based or university sites. Participants Immunocompetent adults (N = 308), aged 18 years or older, with a documented history of ocular HSV disease in the prior year and observed for up to 15 months. Exposure Variables Psychological stress, systemic infection, sunlight exposure, menstrual period, contact lens wear, and eye injury recorded on a weekly log. The exposure period was considered to be the week before symptomatic onset of a recurrence. Main Outcome Measure The first documented recurrence of ocular HSV disease, with exclusion of cases in which the exposure week log was completed late after the onset of symptoms. Results Thirty-three participants experienced a study outcome meeting these criteria. Higher levels of psychological stress were not associated with an increased risk of recurrence (rate ratio, 0.58; 95% confidence interval, 0.32-1.05; P = .07). No association was found between any of the other exposure variables and recurrence. When an analysis was performed including only the recurrences (n = 26) for which the exposure week log was completed late and after symptom onset, there was a clear indication of retrospective overreporting of high stress (P = .03) and systemic infection (P = .01). Not excluding these cases could have produced incorrect conclusions due to recall bias. Conclusions Psychological stress does not appear to be a trigger of recurrences of ocular HSV disease. If not accounted for, recall bias can substantially overestimate the importance of factors that do not have a causal association with HSV infection

Examining parent and child agreement in the diagnosis of adolescent depression

Background: The diagnosis of depression in adolescents relies on identifying the presence of specific core and additional symptoms. Symptoms can be identified using structured or unstructured interviews and a range of questionnaire measures, which are completed by the young person and by a parent or carer. The aim of this research was to examine the inter- and intra-rater reliability of parent report and adolescent self-report of depression symptoms. Method: In a sample of parent-child dyads, where young people aged 13-17 were referred to a mental health service for depression, we examined adolescents’ (n = 46) and parents’ (n = 46) independent responses to the Schedule for Affective Disorders and Schizophrenia in School-Age Children (Kaufman et al., 1997) and the Mood and Feelings Questionnaire (Costello & Angold, 1988). Results: In the clinical interview, diagnostic criteria were more often met based on the adolescent’s report, and adolescents endorsed more symptoms of depression than their parents. Tentative results also suggest that parent-child agreement about specific symptoms was low. Comparing different measures of depression revealed that adolescent report on the questionnaire and interview was significantly correlated. However, there was no significant correlation between parent questionnaire and interview report. Conclusion: These results suggest that relying solely on parents to identify depression in their children may result in young people with depression being missed and therefore untreated. Young people themselves should be encouraged and enabled to recognise the symptoms of depression, and have an established pathway to services that offer assessment and treatment

Finite element model of intermuscular pressure during isometric contraction of skeletal muscle

The measurement of in vivo intramuscular pressure (IMP) has recently become practical and IMP appears well correlated with muscle tension. A numerical model of skeletal muscle was developed to examine the mechanisms producing IMP. Unipennate muscle is modelled as a two-dimensional material continuum that is incompressible and nonlinearly anisotropic. The finite element technique is used to calculate IMP and muscle stress during passive stretch and during isometric contraction. A novel element models the contractile portion of muscle, incorporating sarcomere length-force and velocity-force relations. A range of unipennate muscle geometries can be modelled. The model was configured to simulate the rabbit tibialis anterior muscle over a range of lengths. Simulated IMP and stress results were validated against animal experimentation data. The simulation agreed well with the experimental data over the range of 0.8-1.1 of the optimal length. Severe pressure gradients were produced near the musculo-tendinous junctions while IMP was more uniform in the central muscle belly. IMP and muscle stress in relaxed (unstimulated) muscle increased nonlinearly with muscle length. IMP and stress in isometrically contracting muscle showed a local maximum at optimal length and were reduced at shorter lengths. At muscle lengths longer than optimal, stress and IMP increased predominately due to tension in the passive elastic structures