Unexplained paralysis in arm is not play-acting

Patients with unexplained paralysis in an arm have brains that work differently. Part of their brain is less active during movement than in healthy individuals or those consciously mimicking that they have a paralyzed arm. Brain imaging shows how the brain is able to unintentionally and unconsciously switch off certain functions such as movement, speech and sight in response to psychological stress. This provides patients and physicians with an important clue to how to treat physical symptoms related to psychological stress, according to a study conducted by brain researcher Marije van Beilen at the University Medical Center Groningen, which will be published today in PLoS ONE.

Van Beilen specifically researched brain activity related to unexplained paralysis in the arms. She used an fMRI scanner to study patients with physically unexplained paralysis as well as 35 healthy volunteers, 14 of whom mimicked paralysis. The participants were asked to move their hand and to imagine that they were moving their hand. This meant she was able to compare patients with healthy individuals mimicking the condition or moving their hand normally.

Research results

Research showed that two parts of the brain are less active in the patients. The first of these, the precuneus, is the part of the brain that is primarily involved in psychological functions, such as consciousness, self-reflection and memory related to personal life experiences. The finding that activation in this area is decreased, provides more insight in how psychological factors, such as stress or depression, can cause physical symptoms. The second part of the brain, the gyrus supramarginalis, is involved in movement. This part of the brain is less active in the patients, including when they use their healthy arm and even when only thinking about movement.

Meaning of the results

Patients and physicians now know that unexplained physical complaints can be accompanied by abnormal brain functioning. Such complaints that are ‘all in the mind’ often lead to irritation between doctors and patients. The doctors are unable to adequately help a large group of patients and patients may feel that they are seen as play-acting. The results of Van Beilen’s research may well change the general medical view on physical complaints which are not sufficiently understood. She hopes that understanding between patients and physicians will grow and that opportunities for treatment will increase as well as motivation to seek treatment.

Insufficiently explained physical complaints

Such insufficiently explained physical complaints occur often and take many different forms, such as unexplained pain (for example abdominal pain, muscle pain, headache), fatigue, neurological complaints and gynaecological complaints. Physical symptoms often occur in combination with psychological stress, and these symptoms can then become chronic. Such complaints are not intentionally feigned. The symptoms are, however, nearly identical to intentionally mimicked complaints, and this can give patients the feeling that they are not being taken seriously.