A study of persistent post-concussion symptoms in mild head trauma using positron emission tomography.

BACKGROUND: Complaints of persistent cognitive deficits following mild head trauma are often uncorroborated by structural brain imaging and neuropsychological examination. OBJECTIVE: To investigate, using positron emission tomography (PET), the in vivo changes in regional cerebral uptake of 2-[(18)F]fluoro-2-deoxy-D-glucose (FDG) and regional cerebral blood flow (rCBF) in patients with persistent symptoms following mild head trauma. METHODS: Five patients with mild head trauma and five age and education matched healthy controls were imaged using FDG-PET to measure differences in resting regional cerebral glucose metabolism. Oxygen-15 labelled water (H(2)(15)O)-PET was also used to measure group differences in rCBF changes during a spatial working memory task. In addition, neuropsychological testing and self report of dysexecutive function and post-concussion symptoms were acquired to characterise the sample. RESULTS: There was no difference between patients and controls in normalised regional cerebral FDG uptake in the resting state in frontal and temporal regions selected a priori. However, during the spatial working memory task, patients had a smaller increase in rCBF than controls in the right prefrontal cortex. CONCLUSIONS: Persistent post-concussive symptoms may not be associated with resting state hypometabolism. A cognitive challenge may be necessary to detect cerebral changes associated with mild head trauma.

Volitional control of homonymous hemianopsia: a single case study.

A 52-year-old woman suffered a posterior left hemisphere infarction involving the geniculo-striate system with right homonymous hemianopsia. Eighteen months after the stroke, we used perimetry and PET imaging of cerebral blood flow to demonstrate the patient's volitional control over the size of the scotoma. The volitional control could be eliminated with competing cognitive tasks. Significant increases in cerebral blood flow in contralateral medial prefrontal cortex, and in ipsilateral dorsolateral frontal convexity, temporoparietal and insular cortex were associated with volitional control of the visual field defect.

Psychosocial outcome following individualized neuropsychological rehabilitation of brain damage.

At the center for Rehabilitation of Brain Damage, University of Copenhagen, 46 consecutively admitted brain-damaged patients with varying pathologies and who were on average 2.9 years post-injury were treated in a daily four-month rehabilitation program in groups of about 10, followed by a six-month period of contact varying according to individual needs. An evaluation of psychosocial outcome is presented. The results, based on comparisons between pre-, post-treatment and follow-up questionnaire data, show continuing functional improvements in the areas of family life and living conditions. Dependence on health services declined. Over 70% of the patients returned to either work, further education or voluntary work activities. For the whole group, leisure activities returned to the pre-injury level. Follow-up at about two years revealed continuing improvements in all areas, suggesting social readaptation to a degree above expectations as judged from the existing literature.

Quantitative and qualitative aspects of memory performance after minor head injury.

Neuropsychological investigation of minor head injury (MHI) has consistently corroborated patient subjective complaints of memory loss. An experimental group of 11 minor head-injured patients and a control group of age-matched normal volunteers were compared on the California Verbal Learning Test (CVLT) and on the Rey-Osterreith complex figure. Minor head-injured subjects were found to be impaired on measures of short-term and delayed free recall as well as on measures of organizational-semantic strategy in the retrieval phase. These findings are consistent with subjective reports from the patients and may in part explain reduced psychosocial and vocational adaptation following minor head injury.

Neuropathological determinants of acquired attention disorders in traumatic brain injury.

Attentional disorders are frequently mentioned neuropsychological sequalae following traumatic brain injury (TBI). However, little is known about the recovery of attention, or the determinants of variability of attentional functioning following TBI. The present study was undertaken to examine (1) the extent to which attentional disorders are present among patients at various chronicity stages following TBI, (2) differences in performance on a number of measures of attention as a function of different clinical-neuropathological syndromes. A sample of 70 TBI subjects were rated according to different clinical-neuropathological syndromes and neuropsychologically evaluated. The results suggest that TBI patients of different chronicity stages, with significantly different lengths of coma, did not significantly differ in terms of the type or severity of attentional disorders. However, when the same patients were classified according to clinical-neuropathological syndromes, significant differences in the severity and type of attentional disorders were evident. The findings were interpreted to suggest that typical indices of severity of TBI do not correlate with the severity and type of attentional disorders and that qualitative aspects of the subjects' pathology may be more important in determining the nature of the attentional disorders.