In order to provide the best possible treatment for brain fatigue, a thorough investigation is necessary. Early treatment and information can alleviate and prevent unnecessary suffering that often occurs when brain fatigue causes frustration and despair. 

A medical examination is needed to rule out other diagnoses and underlying problems. There may be various causes, such as illness or injury that affect the brain, but also, for example, depression, pain, cognitive impairments, and other diseases.

Neuropsychological assessment is of value in assessing cognitive status in a person suffering from brain fatigue. When suffering from brain fatigue, neuropsychological tests may primarily show decreased processing speed and impaired attention, but in many cases neuropsychological assessment with such results is completely within normal range. There is currently no neuropsychological test to show that the person is suffering from brain fatigue. 

People often complain that they have gotten very tired after the test and that the recovery was long. 

An assessment with an occupational therapist is often of great value and can give the individual a good insight into how it works. This will also be a good help for planning treatment and strategies that can be used. 

It is very important to investigate how to store enough mental energy over time. It must be possible to perform an activity again and again throughout the working day, and also for much longer periods.

The Mental Fatigue Scale (MFS) estimation scale can provide good guidance (see below). If the sum score of the MFS exceeds 10.5 points (the daily variation should not be included in the total) there is suspicion of problems with brain fatigue. Then there is a need for a deeper investigation and a review of actual life situations with work and leisure activities (read more on this under Treatment). MFS also has a therapeutic value that helps individuals to get an explanation for the various symptoms that often occur.