- What is pseudobulbar affect? How is it screened for and determined to be the cause of bursts of crying or laughing?
Pseudobulbar affect (PBA) is a disorder of emotional regulation that occurs in about 10% of people with MS.
The behavior itself is quite striking and easily recognized by those who know what they are looking for; The key feature is the abrupt onset of involuntary laughter or crying that is either out of proportion to the mood state (e.g. something mildly sad that may normally cause a person to sigh may cause an individual with PBA to burst out in near hysterical crying) or totally incongruous with the mood state (person uncontrollably laughs at something others find sad). It is this loss of congruence with the mood state, plus the abrupt onset followed by cessation of the laughter or crying within seconds or minutes, that distinguishes PBA from depression or grief. Unless significant cognitive problems are present, the person is usually aware that the laughing and crying is inappropriate and is embarrassed by their behavior. In early or milder cases the response is more blunted, such as an inappropriate chuckle or a smirk on the face that seems inappropriate.
Although it can be observed at all stages of MS it is far more common in patients with more advanced disease. PBA actually occurs more often in several other neurological diseases, particularly Amyotropic Lateral Sclerosis (ALS), and is therefore not at all specific for MS. It has gone by many different names over the more than 125 years since initially described in the medical literature, including pathological laughing and crying and emotional dyscontrol syndrome, but most theories continue to suggest it is caused by damage to the neural circuits in the central nervous system responsible for normal inhibitory control of emotions. Once inhibition is lost, emotions are unleashed in this unpredictable manner.
There is a survey people can take to determine if PBA is a possible cause of emotional outbursts. This is called the Center for Neurological Study-liability Scale for Pseudobulbar affect. This is provided at the end of this blog. Scores greater than 13 indicate that PBA may be cause of your behavior.
Treatments are available if necessary and partially effective. These include older drugs such as amitriptyline and fluoxetine and a newer drug called Nuedexta (made by Avanir) that is a combination of dextromethorphan (a cough suppressant in most cold remedies) and quinidine (an older drug used in higher doses to control irregular heart rhythms). This is the type of problem that neurologists are trained to recognize and treat as needed.
Don't forget to click on the file below to download the CNS questionnaire to determine if PBA is a possible cause of emotional outbursts.