Diagnostic criteria for pseudobulbar affect

Two sets of published diagnostic criteria are available to help differentiate PBA from depression. The first set of diagnostic criteria was developed by Poeck in 1969.3 These 4 criteria include: 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, and expression of the emotion does not lead to a feeling of relief. The second set of diagnostic criteria was developed by Cummings et al in 2006.4 These criteria describe a change from previous emotional responses, inconsistent with or disproportionate to mood, not dependent on a stimulus, or are excessive relative to that stimulus, cause significant distress or social/occupational impairment, are not accounted for by another psychiatric or neurologic disorder, and are not due to a drug.


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These uncontrollable episodes of crying or laughter come with a great deal of social anxiety. Patients with PBA have no control over when these outbursts will occur or how long they will last. They are unable to voluntarily stop these episodes once they begin. This can be extremely embarrassing for these patients especially when the episodes occur in inappropriate situations and settings. Many patients with PBA experience social isolation as they avoid situations where they are in the presence of people who do not understand what may be happening to them. Because this disease leads to severe social anxiety, embarrassment, and social isolation, proper diagnosis and appropriate treatment are imperative.

Treatment

The goal of treatment of PBA is to diminish the severity and frequency of episodes. The targets of treatment are primarily norepinephrine, serotonin, or glutamate, using tricyclic antidepressants (TCAs), SSRIs, and the cough suppressant dextromethorphan.1 Prior to approval by the US Food and Drug Administration of the combination of dextromethorphan hydrobromide and quinidine sulfate (Nuedexta®), all treatments had been off-label. The treatment combines dextromethorphan hydrobromide (20 mg), the ingredient active in the central nervous system, and quinidine sulfate (10 mg), a metabolic inhibitor that enables dextromethorphan to reach therapeutic concentrations. Although the mechanism by which the drug exerts therapeutic effects in patients with PBA is unknown, it acts on sigma-1 N-methyl-D-aspartate receptors in the brain and spinal cord. Studies to support the effectiveness of dextromethorphan/quinidine were performed in patients with ALS and MS. In the STAR (Safety, Tolerability, and Efficacy Results Trial of AVP-923 in PBA; ClinicalTrials.gov Identifier: NCT00573443) clinical trial, the primary outcome measure — the number of laughing and crying episodes — was significantly lower in those treated with the drug combination compared with those receiving placebo. Although the mechanisms are not fully understood, serotonergic and glutamatergic transmission appear to play major roles, and there are clear therapeutic benefits in treatment for PBA with SSRIs, TCAs, or dextromethorphan/quinidine.

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The number of individuals with neurologic conditions is substantial, and many of these also experience PBA, which can cause emotional distress due to social anxiety, embarrassment, and social isolation. With nearly 2 million individuals in the United States experiencing the uncontrollable crying and/or laughing of PBA, this represents a significant national health issue in need of attention from primary care providers. Lack of familiarity with the disorder by patients, caregivers, and clinicians may be contributing to the underrecognition and undertreatment of PBA. Primary care providers can contribute to raising awareness of PBA and its treatment options by sharing resources with patients and their families.  Resources for patients with PBA and their caregivers are available online at The National Stroke Association, the Multiple Sclerosis Association of America, and PBAInfo.

References

Ahmed A, Simmons Z. Pseudobulbar affect: prevalence and managementTher Clin Risk Manag. 2013;9:483-449.

Brooks BR, Crumpacker D, Fellus J, Kantor D, Kaye RE. PRISM: A novel research tool to assess the prevalence of pseudobulbar affect symptoms across neurological conditions. PLoS One. 2013;8(8):e72232.

Poeck K. Pathophysiology of emotional disorders associated with brain damage. In: Vinken PJ, Bruyn GW (eds). Handbook of Clinical Neurology. Volume 3. Amsterdam: North Holland Publishing; 1969:343-367.

Cummings JL, Arciniegas DB, Brooks BR, et al. Defining and diagnosing involuntary emotional expression disorder. CNS Spectr. 2006;11(6):1-7.

Garnock-Jones KP. Dextromethorphan/quinidine. CNS Drugs. 2011;25(5):435-445.