Citation

Hou J, Nelson R, Wilkie Z, Mustafa G, Tsuda S, Thompson FJ, Bose PK. J. Neurotrauma 2017; 34(16): 2456-2466.

Affiliation

Malcom Randal VA Medical Center, BRRC (151) , 1601 SW Archer Rd , Gainesville, Florida, United States , 32608-1135 ; pkbose@ufl.edu.

Copyright

(Copyright © 2017, Mary Ann Liebert Publishers)

DOI

10.1089/neu.2016.4851

PMID

28376701

Abstract

Traumatic brain injury (TBI) can produce life-long disabilities including anxiety, cognitive, balance, and motor deficits. The experimental model of closed head TBI (cTBI) induced by weight drop / impact acceleration is known to produce hallmark TBI injuries. However, comprehensive long-term characterization of co-morbidities induced by graded mild to mild/moderate intensities using this experimental cTBI model has not been reported. The present study used two intensities of weight drop (1.0 m and 1.25 m/450 g) to produce cTBI in a rat model to investigate initial and long-term disability of four comorbidities: anxiety, cognitive, vestibulomotor, and spinal reflex that related to spasticity. The TBI and sham injuries were produced under general anesthesia. The time for righting recoveries following TBI, recorded to estimate the duration of unconsciousness, revealed that the TBI mild/moderate group required a mean of 1 minute 27 sec longer than the values observed for non-injured sham animals. Screening MRI images revealed no anatomical changes, mid-line shifts, or hemorrhagic volumes. However, compared with sham injuries, significant long-term anxiety, cognitive, balance, and physiological changes in motor reflex related to spasticity were observed post-TBI for both TBI intensities. The longitudinal trajectory of anxiety and balance disabilities tested at 2 wk, 4 wk, 8 wk, and 18 wk revealed progressively worsening disabilities. In general, disability magnitudes were proportional to injury intensity for three of the four measures. A natural hypothesis would pose that all disabilities would increase incrementally relative to injury severity. Surprisingly, anxiety disability progressed over time to be greater in the mildest injury. Collectively, translational implications of these observations suggest that patients with mild TBI should be evaluated longitudinally at multiple time points, and that anxiety disorder could potentially have a particularly low threshold for appearance and progressively worsen following injury.

Language: en

Keywords

COGNITIVE FUNCTION; MODELS OF INJURY; OUTCOME MEASURES; TRAUMATIC BRAIN INJURY