Pseudobulbar Affect: When You Can't Stop Laughing, or Crying

Nov. 4, 2010— -- When David Diehl, a third-generation family farmer, became a paraplegic five days after an autoimmune condition attacked his spinal cord in 1991, he began driving his tractor and combine using rails and his hands. When his doctor diagnosed multiple sclerosis in 1998, he made adjustments. When the MS left him blind in his left eye in 2000, he relied on faith and family to move beyond it.

But what really threw him was breaking into uncontrollable laughter at a friend's funeral three years ago, when he bit his tongue so hard to stifle it that "I could almost taste blood."

That involuntary laughter, and sudden, uncontrollable crying jags, are part of a neurological disorder that left Diehl, of East Helena, Mont., confused and apologetic. The inappropriate emotional outbursts during serious heart-to-heart talks with his wife Arlene stressed their otherwise rock-solid 35-year marriage. She missed her formerly good-natured husband. It wasn't easy to have him interrupt a serious talk by laughing at her.

"It would really inflame things," she said. "I would try to communicate to him that his reaction wasn't normal, but he really couldn't see it."

Diehl, now 55, felt frustrated and embarrassed because "the outward expression did not match what was going on inside."

Ultimately, a neurologist 90 miles away in Great Falls, Mont., explained that the MS wasn't causing this disconnect between Diehl's emotions and outbursts. Instead, the doctor diagnosed pseudobulbar affect, which can accompany such neurological conditions as MS, amyotrophic lateral sclerosis (Lou Gehrig's disease), Parkinson's disease, brain tumors, and traumatic brain injury.

PBA interferes with relationships and employment in patients already grappling with loss of control over their brains and bodies. The effects can range from occasional to constant, from mild to crippling.

It's not a new condition; it was noted as early as 1872, when naturalist Charles Darwin wrote, "Certain brain diseases, such as hemiplegia, brain-wasting, and senile decay, have a special tendency to induce weeping."