ORLANDO – The prevalence of pseudobulbar affect symptoms – that is, uncontrollable, disruptive outbursts of crying and/or laughing – is considerably greater across a range of neurologic disorders than previously appreciated, according to the largest-ever study to screen for this condition.
Pseudobulbar affect (PBA) symptoms were found in the study to be more common among neurology patients under age 65; however, the adverse impact of PBA symptoms upon quality of life was greater in the elderly, Dr. David W. Crumpacker reported at the annual meeting of the American Association for Geriatric Psychiatry.
He presented the results of the PRISM (PBA Registry Series) study, which enrolled 5,290 patients on the basis of having any of six neurologic disorders: Alzheimer’s disease, amyotrophic lateral sclerosis (ALS), multiple sclerosis, Parkinson’s disease, stroke, or traumatic brain injury. They were screened for the presence of PBA symptoms using the validated Center for Neurologic Study–Lability Scale (CNS-LS). A score of 13 or more was deemed positive, based upon its demonstrated good predictive value for physician diagnosis of PBA in patients with ALS.
The CNS-LS is a simple test that can be completed quickly by either the patient or caregiver. The test is well-suited for routine use in clinical practice, noted Dr. W. Crumpacker, a psychiatrist at Baylor University Medical Center, Dallas.
The overall prevalence of PBA symptoms among the 3,048 PRISM participants aged 65 years or older was 27.4%, with the highest rate seen in patients having ALS (see chart). In contrast, the prevalence of PBA symptoms among patients under age 65 years was 49.5%, with the highest rate – 56.9% – being seen in traumatic brain injury patients.
Patients or caregivers were asked to rate on a 0-10 scale the impact their primary neurologic disease has had on their quality of life. Patients 65 years and older with PBA symptoms reported a significantly greater negative impact than did those without PBA symptoms, with mean scores on the quality of life impact scale of 6.3 vs. 4.6. The quality of life difference between those with PBA symptoms and those without was significant for patients with each of the neurologic diseases except for ALS.
Dr. David Crumpacker
As another measure of the adverse impact of having PBA symptoms, 56% of affected older patients were on at least one antipsychotic or antidepressant, compared with 35% of older patients without PBA symptoms.
PBA is thought to result from injury to neurologic pathways that regulate emotional expression as a secondary consequence of a variety of neurologic disorders.
In an interview, Dr. Crumpacker said PBA is greatly underdiagnosed and often gets misdiagnosed as depression.
"The symptoms are extremely disturbing to others, and patients are acutely aware of that. I tell my friends in neurology, it’s the psychiatric pathology that causes people problems in their lives. No one gets divorced over neurologic pathology, they get divorced over psychiatric pathology. It’s not, ‘I got a divorce because he had a stroke.’ " "It’s "We got divorced because he had a stroke and it changed his personality; he was a different person and I couldn’t be around him anymore,’ " the psychiatrist said.
PBA became a diagnosable disorder with its own ICD-9 code, albeit a diagnosis that can’t be made in the absence of neurologic pathology, at the behest of the Food and Drug Administration, Dr. Crumpacker explained. The impetus was the discovery of an effective treatment, dextromethorphan HBr and quinidine sulfate (Nuedexta), which received FDA approval for PBA 3 years ago.
Nuedexta’s development as the sole medication indicated for PBA was serendipitous, according to Dr. Crumpacker.
"The drug was being tested in Alzheimer’s disease. The jury is still out on whether it helps. But families of study participants came back saying, ‘You know that stuff dad used to do – the crying, the inappropriate laughter, the anger? He doesn’t do those kinds of things anymore,’ " Dr. Crumpacker recalled.
He reported serving on a scientific advisory board for Avanir Pharmaceuticals, which markets Nuedexta.