Examining Sex Differences in Relationships Between Subjective and Objective Measures of Upper Extremity Motor Impairment in a Sample of Stroke Survivors.

BACKGROUND AND PURPOSE: Rehabilitation professionals use subjective and objective outcome measures to assess stroke-related impact and impairment. Understanding if subjective and objective findings correlate among stroke survivors, especially if these associations differ between females and males, can inform care decisions. METHODS: A retrospective cross-sectional design was used, with data selected from subacute to chronic stroke survivors on age, time since stroke, the hand domain from the Stroke Impact Scale version 3.0 (SIS-H), and the Fugl-Meyer Upper Extremity (FMUE) Assessment. Group differences were assessed for all outcomes based on sex and time poststroke. Separate correlations for females and males were performed between the subjective (SIS-H) and objective measures (FMUE) of upper limb function and impairment. RESULTS: Data from 148 participants (44 females) were included in this study. SIS-H was significantly correlated with FMUE in both females and males ( P s ≤ 0.001). No significant differences were found between the groups' mean SIS-H or FMUE scores based on sex or time poststroke. DISCUSSION AND CONCLUSIONS: Subjective and objective measures of physical functioning were correlated in both females and males. Although we found no sex differences in our primary outcomes, the sample size of females was disproportionately lower than the males. This is consistent with an ongoing problem in the stroke recovery research field, where females are often underrepresented and understudied, and where females who experience higher levels of impairment are less likely to participate in research.

Females exhibit smaller volumes of brain activation and lower inter-subject variability during motor tasks.

Past work has shown that brain structure and function differ between females and males. Males have larger cortical and sub-cortical volume and surface area (both total and subregional), while females have greater cortical thickness in most brain regions. Functional differences are also reported in the literature, yet to date little work has systematically considered whether patterns of brain activity indexed with functional magnetic resonance imaging (fMRI) differ between females and males. The current study sought to remediate this issue by employing task-based whole brain motor mapping analyses using an openly available dataset. We tested differences in patterns of functional brain activity associated with 12 voluntary movement patterns in females versus males. Results suggest that females exhibited smaller volumes of brain activation across all 12 movement tasks, and lower patterns of variability in 10 of the 12 movements. We also observed that females had greater cortical thickness, which is in alignment with previous analyses of structural differences. Overall, these findings provide a basis for considering biological sex in future fMRI research and provide a foundation of understanding differences in how neurological pathologies present in females vs males.

Following Spinal Cord Injury Transected Reticulospinal Tract Axons Develop New Collateral Inputs to Spinal Interneurons in Parallel with Locomotor Recovery.

The reticulospinal tract (RtST) descends from the reticular formation and terminates in the spinal cord. The RtST drives the initiation of locomotion and postural control. RtST axons form new contacts with propriospinal interneurons (PrINs) after incomplete spinal cord injury (SCI); however, it is unclear if injured or uninjured axons make these connections. We completely transected all traced RtST axons in rats using a staggered model, where a hemisection SCI at vertebra T10 is followed by a contralateral hemisection at vertebra T7. In one group of the animals, the T7 SCI was performed 2 weeks after the T10 SCI (delayed; dSTAG), and in another group, the T10 and T7 SCIs were concomitant (cSTAG). dSTAG animals had significantly more RtST-PrIN contacts in the grey matter compared to cSTAG animals (p < 0.05). These results were accompanied by enhanced locomotor recovery with dSTAG animals significantly outperforming cSTAG animals (BBB test; p < 0.05). This difference suggests that activity in neuronal networks below the first SCI may contribute to enhanced recovery, because dSTAG rats recovered locomotor ability before the second hemisection. In conclusion, our findings support the hypothesis that the injured RtST forms new connections and is a key player in the recovery of locomotion post-SCI.

Effects of a switch from tenofovir- to abacavir-based antiretroviral therapy, with or without atazanavir, on renal function.

INTRODUCTION: Tenofovir disoproxil fumarate (TDF)-associated renal dysfunction may abate when TDF is replaced with abacavir (ABC). The extent to which the third drug atazanavir contributes to renal dysfunction is unclear. METHODS: A retrospective analysis was conducted on adults who had plasma viral load (pVL)<200 copies/mL for≥six months while receiving TDF/lamivudine (3TC) - or TDF/emtricitabine (FTC)-based antiretroviral therapy (ART), then switched to ABC/3TC while retaining the third drug in the ART regimen. CD4, pVL, creatinine, estimated glomerular filtration rate (eGFR), serum phosphorus, urine albumin to creatinine ratio and serum lipids were compared between pre-switch baseline and 3, 6 and 12 months after the switch to ABC. RESULTS: A total of 286 patients switched from TDF to ABC between 2004 and 2014: 232 (81%) male, median age 48 years (interquartile range (IQR) 42, 56). The third drug was atazanavir (± ritonavir) in 141 (49%) cases. The pVL was<50 copies/mL in 93 to 96% at all time points. Median serum creatinine was 93 µmol/L (IQR 80-111) at baseline and decreased to 88 µmol/L (IQR 78-98) at 12 months after the switch to ABC. Median eGFR increased from 74 (IQR 60-88) mL/min at baseline to 80 mL/min (IQR 69-89) at 12 months. Results were not significantly different between patients on atazanavir versus those on another third drug. CONCLUSIONS: Viral suppression was maintained among patients who switched from TDF/3TC or TDF/FTC to ABC/3TC. Serum creatinine and eGFR improved up to 12 months after switching to ABC/3TC, irrespective of whether or not patients were also receiving atazanavir±ritonavir.