OBJECTIVESFatigue after an acquired brain injury is common, and is characterized by limited energy reserves to accomplish ordinary daily activities. A typical characteristic of mental fatigue is that the mental exhaustion becomes pronounced during sensory stimulation or when cognitive tasks are performed for extended periods without breaks. There is a drain of mental energy upon mental activity in situations in which there is an invasion of the senses with an overload of impressions, and in noisy and hectic environments. Another typical feature is a disproportionally long recovery time needed to restore the mental energy levels after being mentally exhausted. The mental fatigue is also dependent on the total activity level as well as the nature of the demands of daily activities. For many people, there is an increased risk of doing too much and becoming even more fatigued.METHODSWe have developed an application for Windows Phone for assessment of mental fatigue. The Mental Fatigue Scale is used. The MFS is a multidimensional questionnaire containing 15 questions. The questions included in the MFS are based on symptoms described following longitudinal studies of patients with TBI, brain tumours, infections or inflammations in the nervous system, vascular brain diseases, and other brain disorders. The app also includes information about mental fatigue.   RESULTSThis application can help people determine the level of mental fatigue and it can also serve to provide an overall picture of the severity of the condition, and detect changes in mental fatigue over time. The scores will be added up and the results will be presented in the form of a rating scale and a diagram. People can then see their results for one week ago, one month ago or a whole year ago. Today, the most important recommendations are to adapt to the energy available by doing one thing at a time, resting regularly and not overdoing things. However, this is challenging for most people and it may take a long time, even years, to adapt to a sustainable level. It may also be difficult for the person to learn by himself/herself and it can take several years of considerable struggle, frustration, despair and depression, to find the right balance between rest and activity. This app can help people to be aware of mental fatigue. If they connect the results to daily activities, the app may also help them to be more aware about what may alleviate and what may make mental fatigue worse. CONCLUSIONSWith regular assessment of mental fatigue, this app may give feedback and support in order to achieve an enduring balance between activities and rest.

The application can be downloaded without cost: http://www.windowsphone.com/en-us/store/app/mental-fatigue/87d4cb88-c9b5-4ac9-9a92-b63a5d8f4d82