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Updated: Jun 18, 2026

Investigations on Alterations of Hippocampal Circuit Function Following Mild Traumatic Brain Injury
Published on: November 19, 2012
Mental fatigue and impaired information processing after mild and moderate traumatic brain injury
Birgitta Johansson1, Peter Berglund, Lars Rönnbäck
1Department of Clinical Neuroscience and Rehabilitation, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Sweden. birgitta.johansson2@vgregion.se
Primary Objective:
Mental fatigue is a common symptom after brain injury. Its mechanisms are not fully understood and it has been difficult to find an objective way of measuring it. The aim was to compare cognitive tests with a new self-assessment questionnaire about mental fatigue.
Methods And Procedures:
Individuals reporting mental fatigue for 6 months or more after mild traumatic brain injury (MTBI) or traumatic brain injury (TBI) and controls were assessed for subjective fatigue, information processing speed, working memory and attention. Depression and anxiety were also assessed in the individuals with brain injury.
Results:
Individuals with MTBI or TBI reported significantly more problems with mental fatigue and related symptoms than controls. A significantly decreased information processing speed (digit symbol-coding, reading speed, trail making test) was found in those on sick leave due to MTBI or TBI, compared to controls. Divided attention was affected to a lesser extent and no effect was detected on working memory.
Conclusion:
Mental fatigue after MTBI can last for several years. It can be profoundly disabling and affect working capacity as well as social activities. Subjective mental fatigue following brain injury is suggested to mainly correlate with objectively measured information processing speed.
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Amnesia
The severity and duration of memory loss vary depending on the type and underlying cause. Amnesia is classified into two main types: retrograde and anterograde.
Retrograde amnesia is marked by the loss of memories formed before the onset of the condition. Patients may recall distant past events but often forget those occurring shortly before the incident.
Anterograde...

