What Is a Minor Stroke?

Background and Purpose— The term “minor stroke” is often used; however a consensus definition is lacking. We explored the relationship of 6 “minor stroke” definitions and outcome and tested their validity in subgroups of patients. Methods— A total of 760 consecutive patients with acute ischemic strokes were classified according to the following definitions: A, score ≤1 on every National Institutes of Health Stroke Scale (NIHSS) item and normal consciousness; B, lacunar-like syndrome; C, motor deficits with or without sensory deficits; D, NIHSS ≤9 excluding those with aphasia, neglect, or decreased consciousness; E, NIHSS ≤9; and F, NIHSS ≤3. Short-term outcome was considered favorable when patients were discharged home, and favorable medium-term outcome was defined as a modified Rankin Scale score of ≤2 at 3 months. The following subgroup analyses were performed by definition: sex, age, anterior versus posterior and right versus left hemispheric stroke, and early (0 to 6 hours) versus late admission (6 to 24 hours) to the hospital. Results— Short-term and medium-term outcomes were most favorable in patients with definition A (74% and 90%, respectively) and F (71% and 90%, respectively). Patients with definition C and anterior circulation strokes were more likely to be discharged home than patients with posterior circulation strokes (P=0.021). The medium-term outcome of older patients with definition E was less favorable compared with the outcome of younger ones (P=0.001), whereas patients with definition A, D, and F did not show different outcomes in any subgroup. Conclusions— Patients fulfilling definition A and F had best short-term and medium-term outcomes. They would be best suited to the definition of “minor stroke.”

Impact of chorioamnionitis and preeclampsia on neurodevelopmental outcome in preterm infants below 32 weeks gestational age

ABSTRACT Aim: Intrauterine conditions may interfere with fetal brain development. We compared the neurodevelopmental outcome between infants <32 weeks gestational age after maternal preeclampsia or chorioamnionitis and controls. Methods: Case-control study on infants with maternal preeclampsia, chorioamnionitis and controls (each n = 33) matched for gestational age. Neurodevelopment at two years was assessed with the Bayley Scales of Infant Development II. Results: Ninety-nine infants were included with a median gestational age of 29 weeks (range 25-32). Median mental developmental index (MDI) was 96 in the control, 90 in the chorioamnionitis and 86 in the preeclampsia group. Preeclampsia infants had a lower MDI compared with the control group (univariate p = 0.021, multivariate p = 0.183) and with the chorioamnionitis group (univariate p = 0.242; multivariate p = 0.027). Median psychomotor index was 80.5 in the control, 80 in the preeclampsia and 85 in the chorioamnionitis group, and was not different between these three groups (p > 0.05). Chorioamnionitis or preeclampsia exposure was not associated with major neurodevelopmental impairments (cerebral palsy, MDI<70, PDI<70). Conclusion: The results of this preliminary study suggest that preeclampsia and chorioamnionitis play a relatively minor role among risk factors for adverse neurodevelopment outcome. Postnatal factors such as ventilation and bronchopulmonary dysplasia may have a greater impact on neurodevelopmental outcome.

Biomechanical model of human cornea based on stromal microstructure

The optical characteristics of the human cornea depends on the mechanical balance between the intra-ocular pressure and intrinsic tissue stiffness. A wide range of ophthalmic surgical procedures alter corneal biomechanics to induce local or global curvature changes for the correction of visual acuity. Due to the large number of surgical interventions performed every day, a deeper understanding of corneal biomechanics is needed to improve the safety of these procedures and medical devices. The aim of this study is to propose a biomechanical model of the human cornea, based on stromal microstructure. The constitutive mechanical law includes collagen fiber distribution based on X-ray scattering analysis, collagen cross-linking, and fiber uncrimping. Our results showed that the proposed model reproduced inflation and extensiometry experimental data [Elsheikh et al., Curr. Eye Res., 2007; Elsheikh et al., Exp. Eye Res., 2008] successfully. The mechanical properties obtained for different age groups demonstrated an increase in collagen cross-linking for older specimens. In future work such a model could be used to simulate non-symmetric interventions, and provide better surgical planning.