Returning Adolescents to Driving after Sports-Related Concussions: What Influences Physician Decision-Making.

OBJECTIVE: To determine which data collected on an initial patient clinic visit for a sports-related concussion (SRC) might influence physicians to clear an adolescent to return to drive (RTD) after injury. STUDY DESIGN: Retrospective cohort study of 189 adolescents with a SRC referred to a hospital-based concussion clinic between June 1, 2015, and May 31, 2016. Subjects were ≥16 years with a valid driver's license (median age = 16, IQR [16, 17]). Concussion evaluations included Post-Concussion Symptom Scale, modified Balance Error Scoring System, and postinjury computerized neurocognitive testing (CNT). Clearance for RTD was the main outcome. Statistical comparisons were conducted with Mann-Whitney U and χ2 tests and logistic regression. RESULTS: In multivariable analysis, odds of being fully cleared to drive were 5.9-fold greater among patients who were administered CNT. Stated symptoms of "headache" and "sensitivity to light" were statistically significantly associated with RTD clearance. For a subset of 113 individuals undergoing CNT, each additional 10-millisecond decrease in simple reaction time was associated with 9% greater odds of being cleared to drive. Each additional 10-millisecond decrease in choice reaction time was associated with 4% greater odds of being cleared to drive. CONCLUSIONS: CNT and associated reaction time measures may facilitate a physician's objective decision-making. Making a RTD determination for adolescents recovering from an SRC should be a core component of a physician's assessment.

On the equivalence between specific adsorption and kinetic equation descriptions of the admittance response in electrolytic cells.

The response of an electrolytic cell, in the shape of a slab, is analyzed in the framework of the Poisson-Nernst-Planck model in the limit of full dissociation. Two different types of boundary conditions on the electrodes are compared. One type describes the exchange of charges between the volume and the external circuit, in the form originally proposed by Chang and Jaffé and later extended to include specific adsorption, where the surface current density is proportional to the variation of the surface bulk density of ions with respect to the value of equilibrium. The other one describes the surface adsorption, in the limit of Langmuir. We show that in the simple case where the ions dissolved in the insulating liquid are identical in all the aspects, except for the sign of the charge, the two models are equivalent only if the phenomenological parameter entering the boundary condition of the Chang-Jaffé model, κ, is frequency dependent, and related to the adsorption coefficient, k(a), in the form κ = iωτ/(1 + iωτ)k(a), where τ is the desorption time and ω the circular frequency of the applied voltage, as proposed long ago by Macdonald.