What Causes Fatigue?
We still don’t fully understand the causes of fatigue, and more research is needed, but a number of contributing factors have been put forward over the years.
Coping with Attention and Processing Information
In 1984, a study proposed a cause of fatigue called the “coping hypothesis” (Van Zomeren et. al., 1984). This suggests that mental fatigue arises due to the constant effort needed to meet the demands of your day to day life. Because living with a traumatic brain injury also involves effort that you expend compensating for other problems with attention and processing information, this can be excessively tiring.
A more recent study by Zinno & Ponsford (2006) examined this relationship in a group of people across a range of severity of traumatic injury. In comparison to a control group, participants in the study experienced higher self-reported and measured fatigue levels following attention-based tasks. Other studies indicate a similar relationship and support the argument for the ‘coping hypothesis’.
Disturbed sleep patterns following brain injury are common. Approximately half of participants in a 2006 study of traumatic brain injury survivors reported sleep complaints (Ouellet et. al. 2006). Nearly a third of the sample met the diagnostic criteria for an insomnia syndrome, almost 3 times greater than the general public. A significant number of participants in that study reported that their sleep disturbances impacted on their mood and mental capacities. It is recognised in the literature that fatigue levels leading from sleep disturbance have an impact on quality of rehabilitation and quality of life.
Depression and anxiety are common problems that arise following a traumatic brain injury, affecting more than 60% of individuals within 5.5 years post injury (Whelan-Goodwison et. al., 2009). A study in 2005 found moderate to strong correlations between depression and fatigue levels and also between anxiety and fatigue levels (Ziino et. al. (2005)). This suggests a complex relationship between traumatic brain injury, mental health difficulties and mental fatigue. Further research into this relationship is needed before we understand it fully.
Hormone Regulation Disorders
Popovic (2005) noted that among individuals who have experienced a TBI, there are frequent hormone regulation disorders. Deficiencies in hormones are associated with a range of difficulties such as decreased physical strength, aerobic ability and well-being which in turn can lead to issues with attention, memory, depression and fatigue.
So overall, the literature points to the ‘coping hypothesis’ as being the most plausible explanation for the mental fatigue experienced by those who have suffered a traumatic brain injury. But to arrive at a more complete understanding of fatigue, we also need to consider the other factors discussed; sleep disturbance, emotional disturbances and changes in hormone secretions.
Fatigue – What you can do
Unfortunately there is currently no effective treatment for mental fatigue. Recommendations for the management of fatigue include;
- Adapting your daily activity or work activity so that it can be managed within your own limits
- Working at a steady pace, completing one task at a time.
- Take regular breaks.
- Eat a balanced diet.
- Regular aerobic exercise (once your GP has given the all clear of course! )
- Mindfulness- A Mindfulness Based Stress Reduction (MBSR) programme has been shown to be a clinically effective tool to alleviate stress and ruminative thoughts and allow people to live in the present which in turn saves mental energy (Johansson et. al., 2012).
Johansson, B, H Bjuhr & L. Ronnback. Mindfulness based stress reductions improves long term mental fatigue after stroke or TBI. Brain Injury (2012) 26(13-14) p. 1621-8.
Ouellet, MC., Beaulieu-Bonneau S., Morrin CM. Insomnia in patients with TBI: Frequency, characteristics and risk factors. Journal of Head Trauma Rehabilitation (2006). 21 (3), 199-212.
Popovic, V. GH deficiency as the most common pituitary deficit after TBI: Clinical implications. Pituitary (2005) 8; 239-43.
Van Zomeren AH, Brouwer BG, Deelman BG. Attentional deficits: The riddles of selectiveity, speed and alertness. In: Brooks D, editor. Closed head injury: psychological, social and family consequences. Oxford: Oxford University Press; 1984, p. 74-107.
Whelan- Goodwinson, R, Ponsford J, Johnston, L & Grant F (2009) Journal of head trauma rehabilitation Vol. 24 (5) pp. 324-332.
Ziino C., Ponsford J. Measurement & prediction of subjective fatigue following TBI. Journal of International Neuropsychological Society (2005) 12: 100-10.
Ziino C., Ponsford J. Vigilance & fatigue following TBI. Journal of International Neuropsychological society (2006); 11: 416-25.