Cognitive sequelae of head injury: Involvement of basal forebrain and associated structures

Wolfson Brain Imaging Centre, University of Cambridge, Addenbrooke's Hospital, Box 65, Cambridge CB2 2QQ, UK.
Brain (Impact Factor: 9.2). 02/2005; 128(Pt 1):189-200. DOI: 10.1093/brain/awh352
Source: PubMed


Traumatic brain injury is the most common cause of death and disability in young people and survivors often suffer from chronic cognitive deficits. From animal, post-mortem and cognitive studies, there is now increased evidence that abnormalities in the cholinergic system may be underlying some of these deficits. This study investigated this hypothesis in a group of survivors of moderate-severe head injury (n = 31). Patients completed a comprehensive neuropsychological assessment and an MRI scan. Compared with a group of controls (matched on age, sex and premorbid intelligence quotient), the patients showed deficits in sustained attention, paired associate learning and reaction time, but comparative preservation of spatial working memory. Voxel-based morphometry revealed reduced grey matter density in the head injured group in the basal forebrain, the hippocampal formation and regions of the neocortex. These cognitive and structural results are consistent with cholinergic dysfunction. These preliminary findings suggest that cholinergic enhancers may be an effective treatment of cognitive deficits post head injury.

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Available from: Doris A Chatfield
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    • "Yet, the association between infratentorial volume and postural impairments has not directly been evaluated. Some studies in TBI patients have demonstrated reduced regional volumes in the cerebellum and brain stem as part of whole brain voxel-based analyses [Bendlin et al., 2008; Gale et al., 2005; Kim et al., 2008; Salmond et al., 2005; Sidaros et al., 2009]. However, standard whole-brain normalization procedures generally lead to relatively poor alignments in infratentorial structures [Diedrichsen, 2006] and, thus, do not allow for a precise localization of the volumetric differences. "
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    ABSTRACT: Many patients with traumatic brain injury (TBI) suffer from postural control impairments that can profoundly affect daily life. The cerebellum and brain stem are crucial for the neural control of posture and have been shown to be vulnerable to primary and secondary structural consequences of TBI. The aim of this study was to investigate whether morphometric differences in the brain stem and cerebellum can account for impairments in static and dynamic postural control in TBI. TBI patients (n = 18) and healthy controls (n = 30) completed three challenging postural control tasks on the EquiTest® system (Neurocom). Infratentorial grey matter (GM) and white matter (WM) volumes were analyzed with cerebellum-optimized voxel-based morphometry using the spatially unbiased infratentorial toolbox. Volume loss in TBI patients was revealed in global cerebellar GM, global infratentorial WM, middle cerebellar peduncles, pons and midbrain. In the TBI group and across both groups, lower postural control performance was associated with reduced GM volume in the vermal/paravermal regions of lobules I-IV, V and VI. Moreover, across all participants, worse postural control performance was associated with lower WM volume in the pons, medulla, midbrain, superior and middle cerebellar peduncles and cerebellum. This is the first study in TBI patients to demonstrate an association between postural impairments and reduced volume in specific infratentorial brain areas. Volumetric measures of the brain stem and cerebellum may be valuable prognostic markers of the chronic neural pathology, which complicates rehabilitation of postural control in TBI. Hum Brain Mapp, 2015. © 2015 Wiley Periodicals, Inc.
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    • "Investigating the properties and neural correlates of such task in the TD population can shed new light on the understanding of sensorimotor integration. In sensorimotor tasks, a functional facilitation or depolarization of the motor cortex may occur to promote a faster and more effective stage of response production to compatible stimuli (Chamberlain and Sahakian, 2004; Salmond et al., 2005). This mechanism is considered to be the basis of the SRC effect, and could help explain possible elements of impairment in clinical groups. "
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    No preview · Article · May 2015 · Neuropsychologia
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    • "Other neuropathological findings in surgical specimens from patients with TLE described granule cell dispersion and temporal lobe sclerosis (47). Other, less frequently affected regions of the brain include selective neurons of the thalamus, basal forebrain, cerebellum, and brain stem (57, 58). "
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