title: Role of the thalamus in natural recovery of cognitive impairment in patients with mild traumatic brain injury.
abstract: Patients with mild traumatic brain injury (mTBI) may have normal neuroimaging but manifest with a broad-spectrum of cognitive-deficits, which may resolve eventually. The function of the thalamus in the process of natural-recovery remains elusive. The current study investigates the role of the thalamus in natural-recovery of cognitive-deficits in patients with mTBI.
  
  
  
  Twenty-one patients with mTBI were evaluated with an initial MRI scan, within 36 hours of injury and assessed with neuropsychological tests(NPT) at 3-4 weeks after injury. First and second follow-up MRI and NPT were performed at 3-4 months and 6-7 months, respectively. The volume and tensor measures of the thalamus and cognitive-scores were analysed at each assessment using repeated-measures of variance. The association of cognitive-scores with corresponding period imaging measures was analysed using bivariate-correlation.
  
  
  
  Serial evaluation showed that all the cognitive-domains improved significantly. During this period there was a significant increase in mean thalamic volume (p = 0.049, effect-size = 0.18). After 3-4 months there was emergence of anisotropic thalamo-cortical connections. At 2-3 weeks and 6-7 months after injury, the alterations in diffusivity values were positively associated with improvement in memory-scores. Improvement in attention-scores correlated significantly with changes in tensor values at the 6-7 months after-injury.
  
  
  
  The correlation between improvement in cognitive-scores and changes in thalamic tensor and volume measures reflect the role of the thalamus in natural-recovery after mTBI.
authors.affiliation: a Department of Clinical Neurosciences.
authors.forename: Ashok
authors.initials: A
authors.lastname: Munivenkatappa
authors.affiliation: b Department of Neurosurgery.
authors.forename: Bhagavatula Indira
authors.initials: BI
authors.lastname: Devi
authors.affiliation: b Department of Neurosurgery.
authors.forename: Dhaval P
authors.initials: DP
authors.lastname: Shukla
authors.affiliation: c Department of Clinical Psychology , National Institute of Mental Health and Neurosciences , Bangalore , India.
authors.forename: Jamuna
authors.initials: J
authors.lastname: Rajeswaran
mesh_terms: D000328:Adult; D000070642:Brain Injuries, Traumatic / Q000150:complications* / Q000000981:diagnostic imaging; D003072:Cognition Disorders / Q000000981:diagnostic imaging / Q000209:etiology*; D056324:Diffusion Tensor Imaging; D005260:Female; D015600:Glasgow Coma Scale; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D009483:Neuropsychological Tests; D020127:Recovery of Function / Q000502:physiology*; D013788:Thalamus / Q000000981:diagnostic imaging / Q000503:physiopathology*; D013997:Time Factors; D055815:Young Adult
keywords: Mild traumatic brain injury; attention; cognitive scores; memory; natural recovery; tensor changes; volume changes