October 7, 2009

Dogs Gone Wild

An expert wonders if seizures could be at the root of Fido’s strange behavior

By Nicholas Dodman

Animals seem to have certain behavior patterns, emotions and memories encoded within specific brain centers. Photo: iStock

A dog I saw several years ago, a Chesapeake Bay retriever, was subject to outbursts so violent that its owner was sometimes left with wounds requiring medical attention. This dog would steal a wine glass and, if the owner tried to take it away, would simply crush the glass in its mouth. With lips and gums bleeding, it would then attack her.

Even if I didn’t know precisely what the problem was, I knew what to call it: rage. Chesapeake Bay retrievers are among the breeds that, like springer spaniels, suffer from bouts of extreme aggression. The phenomenon has long been a mystery to owners and veterinarians alike. But after running an electroencephalogram, I concluded that this dog had much in common with other bizarre cases I’ve seen that didn’t involve aggression at all.

One client informed me that his springer spaniel was a “glugger.” So saying, he produced a videotape. There was the dog standing in the middle of the kitchen looking confused, its pupils widely dilated. Before long it was flicking out its tongue like a lizard, and after that, it started gulping as if it had something stuck in its throat.

Occasionally it would lick the floor and then patrol the periphery of the kitchen, stopping to ingest dust bunnies or other detritus. Next it ran to the back door to be let out. Once in the yard, it eagerly gobbled up great clumps of grass and dirt. Several weeks later, another client informed me that her dog was a “snoofer,” and, yes, this dog exhibited precisely the same behavior. When I showed her the videotape of the glugger, she told me, “That’s my dog.”

Fortunately, I did find a way to help the glugger and the snoofer. The pattern of dysfunctional behavior without significant clinical or laboratory findings led me to diagnose “complex partial seizures”—that is, seizures limited to a discrete region of the brain. I prescribed an anticonvulsant, phenobarbital, and the dogs recovered completely.

Frightened of His Own Shadow

Animals seem to have certain behavior patterns, emotions and memories encoded within specific brain centers. Under normal circumstances, this information would be accessed only when it would serve a useful function. But electrical activation of brain centers during complex partial seizures appears to unleash a Pandora’s box of behavioral and emotional ills.

The seizures that beset the glugger and the snoofer might be traced to a brain center responsible for controlling the impulse to eat. Electrical storms in other regions of the brain evidently cause equally strange yet completely different results.

I once saw a bull terrier that was literally frightened of its own shadow. It was afraid of water as well, and would balk at crossing thresholds, refuse to play with the other dogs and jump a foot in the air if you dropped a manila file on the desk. Sure enough, the neurologist who read the EEG I performed on the dog identified a brainwave pattern associated with complex partial seizures. I suspect that the affected area was the amygdala, a brain center that controls fear. Days after beginning treatment with phenobarbital, the dog improved.

Seizures might also strike parts of the brain that govern predation, and it seems that when they do, they set off yet another variety of unusual behavior. Certain German shepherds circle like whirling dervishes in an attempt to catch their tail, the ultimate prey that rushes away as they chase it. Sadly, some succeed and bite down hard enough to cause injury (I know of one shepherd that bled to death). But the dogs sometimes respond dramatically to treatment with anticonvulsants. So do similarly afflicted bull terriers. Not surprisingly, EEGs that have been done on the terriers reveal weird electrical patterns.

Complex partial seizures are often not recognized as such, but when they are, medical treatment usually brings most symptoms under control. And this holds true even in alarming cases, like that of the maniacal glass-chomping Chesapeake Bay retriever. The EEG suggested that its rage stemmed from seizures in a brain center concerned with affective aggression. Anticonvulsants produced considerable improvement. A dog that might otherwise have been unsuitable as a pet went on to enjoy a peaceful life with its owner.

This article was first published in the Fall 2009 issue of Tufts Magazine.

Professor Nicholas Dodman directs the Animal Behavior Program at the Cummings School of Veterinary Medicine. His latest book is The Well-Adjusted Dog: Dr. Dodman’s Seven Steps to Lifelong Health and Happiness for Your Best Friend (Houghton Mifflin).

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