An Overview of Pseudobulbar Affect in MS

Outbursts of crying and laughter can be symptoms of MS

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Pseudobulbar affect, or PBA, is a syndrome characterized by outbursts of crying or laughter that are inappropriate or exaggerated within the person's social setting. This syndrome can occur in patients with MS and significantly affect their lives, causing feelings of anxiety, embarrassment, and social isolation. The disorder is becoming more widely recognized, however, and effective treatment is available.

The variability of terms used to describe this syndrome has created some confusion among people who suffer from it, as well as within the medical field. Some other terms used to describe pseudobulbar affect include:

  • Involuntary emotional expression disorder
  • Emotional lability or dysregulation or incontinence
  • Pathological laughing and crying
  • Emotionalism
Symptoms of Pseudobulbar Affect in MS
Verywell / JR Bee

Symptoms

PBA manifests itself in excessive displays of emotion, such as:

  • Crying excessively in sad or touching situations, significantly more so than the patient would have cried in the past
  • Laughing uncontrollably in situations that are only mildly amusing and would previously have elicited only a mild chuckle from the patient
  • A striking degree of emotional response by the patient, with the crying or laughter persisting for a considerable period of time and being immune to the individual's efforts to suppress it

Crying appears to be a more common manifestation of PBA than laughter, though both can occur.

Causes

Scientists believe that people with pseudobulbar affect have disrupted nerve signaling within their cerebellum. The cerebellum controls coordination and how the body moves, and scientists believe that it may also help control the body's expression of emotion based on input from other parts of the brain.

While the precise involvement of the cerebellum in pseudobulbar affect is unclear, the main neurotransmitters believed to play a vital role in PBA are serotonin and glutamate. 

Besides MS, there are a number of other neurological disorders associated with the development of pseudo bulbar affect. These include:

  • Alzheimer's disease
  • Traumatic brain injury
  • Stroke
  • Brain tumor
  • Amyotrophic lateral sclerosis (ALS)
  • Parkinson's disease

For people with MS, PBA tends to appear in the later stages, hence people who have had several MS relapses or a progressive, disabling disease course are more susceptible to the syndrome.

Diagnosis

One way a doctor can make a diagnosis of PBA is to talk to a close friend or relative of the patient and/or to the patient himself. The doctor will look for the following "clues" when doing her evaluation:

  • The emotional response is situationally inappropriate.
  • The patient’s feelings and the affective response are not closely related.
  • The duration and severity of the episodes cannot be controlled by the patient.
  • Expression of the emotion does not lead to a feeling of relief.
  • Emotional responses are not the same as they once were.
  • Emotional responses are inconsistent with or disproportionate to mood.
  • Emotional responses are not dependent on a stimulus or are excessive relative to that stimulus.
  • The syndrome causes significant distress or social/occupational impairment.
  • Responses are not accounted for by another psychiatric or neurologic disorder, or drug or alcohol use.

There are also two types of questionnaires that help physicians diagnose pseudobulbar affect. One is the pathological laughing and crying scale (PLACS), in which the clinician interviews the patient. The other is the Center for Neurologic Study–lability scale (CNS–LS), which is a self-reporting questionnaire.

To accurately diagnose PBA, other causes must also be ruled out. Pseudobulbar affect can be missed by doctors because they attribute the crying episodes to depression, which is common in MS. Physicians may do a thorough mental health history to rule out depression in people reporting this effect.

MS vs. Depression

There are some key differences that can help distinguish between these two conditions. One is that in depression, an episode of crying coincides with a low mood. In pseudobulbar affect, a person's episode of crying is inconsistent, exaggerated, or even contradictory with how they really feel. Also, in pseudobulbar affect, a person can switch from crying to laughing within a single outburst.

Another clue is duration: The outbursts of pseudobulbar crying or laughing, tend to come on abruptly and end abruptly, lasting seconds to minutes. An episode of depression, on the other hand, lasts at least two weeks. In addition, depression is associated with other symptoms like a change in sleep habits and appetite, feelings of guilt, and a loss of interest in activities.

In some cases, a doctor will perform an electroencephalogram (EEG) to rule out a rare form of epilepsy that can cause symptoms similar to those of PBA.

Treatment

If your doctor diagnoses you with PBA, you may be prescribed a tricyclic antidepressant, like Elavil (amitriptyline) or nortriptyline, or a selective serotonin reuptake inhibitor (SSRI) such as Celexa (citalopram).

More likely, you may be prescribed Nuedexta (dextromethorphan hydrobromide/quinidine sulfate), which was approved by the U.S. Food and Drug Administration (FDA) in 2010 for the treatment of PBA. Research has found it to be effective for alleviating symptoms of PBA in patients with MS, in addition to patients with ALS.

Side effects of Nuedexta may include diarrhea, dizziness, cough, vomiting, weakness, swelling, urinary tract infections, influenza, and flatulence. While taking this medication, follow-up is important, especially for monitoring of potassium and magnesium levels in the body, which can be reduced with Nuedexta. More monitoring may be needed for people who are at risk for certain rhythm disturbances of the heart. 

A Word From Verywell

PBA can be embarrassing and misunderstood by other people. In addition to seeing your doctor about treatment, it's important to talk to family, friends, and coworkers, explaining what PBA is and how it relates to your MS. This way, if you do find yourself laughing or crying excessively, people will have a better understanding of why you are acting the way you are.

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