Label free, capillary-scale blood flow mapping in vivo reveals that low intensity focused ultrasound evokes persistent dilation in cortical microvasculature.

Non-invasive, low intensity focused ultrasound (FUS) is an emerging neuromodulation technique that offers the potential for precision, personalized therapy. An increasing body of research has identified mechanosensitive ion channels that can be modulated by FUS and support acute electrical activity in neurons. However, neuromodulatory effects that persist from hours to days have also been reported. The brain's ability to provide targeted blood flow to electrically active regions involve a multitude of non-neuronal cell types and signaling pathways in the cerebral vasculature; an open question is whether persistent effects can be attributed, at least partly, to vascular mechanisms. Using a novel in vivo optical approach, we found that microvascular responses, unlike larger vessels which prior investigations have explored, exhibit persistent dilation. This finding and approach offers a heretofore unseen aspect of the effects of FUS in vivo and indicate that concurrent changes in neurovascular function may partially underly persistent neuromodulatory effects.

Differences in vestibulo-ocular reflex time constants in patients with vestibular migraine versus vestibular neuritis/labyrinthitis.

OBJECTIVE: Recurrent dizziness, vertigo, and imbalance, as well as nausea or vomiting, can be induced by central or peripheral vestibular pathology. Vestibular migraine (VM) is a central pathology in which migraines reciprocally interact with vestibular nuclei. Vestibular neuritis and labyrinthitis (VN/L) are peripheral diseases involving inflammation of structures in the vestibular nerve or labyrinth. Because VM and VN/L in early stages can produce similar symptoms, diagnosis may require prolonged clinical evaluation. It has been suggested that differences in a patient's Vestibulo-Ocular Reflex (VOR) measured during the rotary chair step rotation test (RCS Test) can differentiate VM from peripheral pathologies, allowing for faster diagnosis. We sought to compare VOR time constants (VORTcs) in patients with VM versus VN/L, with the goal of exploring potential diagnostic value. STUDY DESIGN: Retrospective chart review of patients seen at a hospital balance center between January 2010 and June 2019. SETTING: Tertiary referral center. PATIENTS: 68 patients (mean age = 58.15, 65 % female, 35 % male) were placed into two groups based on clinical diagnosis codes: 1) VM or 2) VN/L. MAIN OUTCOME MEASURE(S): Primary variable of VORTc, evoked by rotational step testing. RESULTS: Patients in the VM group demonstrated statistically significant elevated VOR Tcs outside the normed range of 10-19.5 compared to those in the VN/L group (p = 0.0003) while patients in the VN/L group demonstrated statistically significant shortened VOR Tcs (p = 0.0443) with the two populations having distinctly different VOR Tc profiles. CONCLUSIONS: Our results support the conclusion that elevated VOR Tcs are a sign of central vestibular pathology and highlight the benefit of utilizing rotary chair testing early in the diagnostic process as a powerful diagnostic tool when evaluating dizzy patients for central versus peripheral vestibular dysfunction. Our results suggest more particularly that elevated VOR Tcs can be utilized to identify patients with vestibular migraine, thus offering differentiation from patients with peripheral vestibular dysfunction earlier in the process of diagnosis, with an opportunity for earlier intervention.

The Effect of Frailty and Patient Comorbidities on Outcomes After Acute Subdural Hemorrhage: A Preliminary Analysis.

BACKGROUND: Frailty is associated with worse outcomes across a variety of neurosurgical diseases. However, its effect on acute subdural hemorrhage (aSDH) outcomes is unclear. The goal of this study is to compare 3 measures of frailty with the gold standard (i.e., initial Glasgow Coma Scale [iGCS] score) for predicting outcomes after aSDH. METHODS: Patients who presented between January 2016 and June 2018 were retrospectively identified based on International Classification of Diseases codes for aSDH. Patients' modified Frailty Index (mFI), temporalis muscle thickness (TMT), and age-adjusted Charlson Comorbidity Index (CCI) were calculated. Primary end points were death and discharge home. RESULTS: Of 167 patients included, the mean age was 63.4 ± 1.9 years, the average CCI was 3.4 ± 0.2, mFI was 1.4 ± 0.1, TMT was 7.1 ± 0.2 mm, and iGCS score was 11.9 ± 0.3. Sixty-nine patients (41.3%) were discharged home and 32 (19.2%) died during hospitalization. In multivariate analysis, decreasing iGCS score (odds ratio [OR], 0.84; 95% confidence interval [CI], 0.74-0.96; P = 0.0112) and midline shift (OR, 1.27; 95% CI, 1.08-1.50; P = 0.0048), but not age or frailty, predicted mortality. In addition to iGCS score (OR, 1.26; 95% CI, 1.10-1.44; P = 0.0011), lower CCI (OR, 0.32; 95% CI, 0.14-0.74; P = 0.0071) and larger TMT (OR, 2.63; 95% CI, 1.16-5.99; P = 0.0210) independently predicted increased rates of discharge home. mFI was not independently associated with either primary end point in multivariate analysis. CONCLUSIONS: iGCS score predicts both mortality and discharge location after aSDH better than do age or frailty. However, CCI and TMT, but not mFI, are useful prognostic indicators of discharge to home after aSDH. The iGCS score should continue to be the primary prediction tool for patients with aSDH; however, frailty may be useful for resource allocation, especially when nearing discharge.