Lost in thought: When cognition changes

Physical abilities aren’t all that’s affected by MS. Thinking, remembering and reasoning can take a hit, too.

by Leslie E. Silverman

Jeffrey Gingold was a litigation attorney in Milwaukee in 1996 when he began experiencing overwhelming fatigue—not just physically, but mentally as well. Diagnosed that year with multiple sclerosis, he began to have trouble concentrating, remembering details and making decisions. “One day in court I turned to look at my client, and suddenly I didn’t know who she was or why I was there,” Gingold, now 53, recalls. “I didn’t want to make mistakes that damaged my partners or clients. When I left my practice in 2001, I walked out the door physically, but cognitively I still had a real problem.”

While Gingold’s experience represents the more severe end of the cognitive dysfunction spectrum, challenges with concentration, memory, organization, planning, reasoning and judgment are common in MS. Nicholas LaRocca, PhD, vice president of Health Care Delivery and Policy Research at the National MS Society, estimates that up to 60 percent of people living with MS experience some degree of cognitive deficits, or “cog fog,” as those who live with the problem sometimes call it.

Cognitive difficulties can occur at any time in the course of the disease, or not at all, Dr. LaRocca says, and they can affect seemingly simple tasks, such as remembering the grocery list, as well as complex activities like organizing a project at work.
MS-related cognitive difficulties fall into three categories:

1. Attention. Staying focused on the task at hand can become difficult. Multitasking and dividing attention are even more problematic.
2. Memory. People have trouble remembering names, recent conversations, appointments and sequential information, like driving directions. But long-term memory is typically not affected, Dr. LaRocca says.
3. Executive functioning. A healthy brain enables people to plan, organize, solve problems and make strong decisions. With MS-related cognitive dysfunction, these processes become especially challenging, particularly when considering multiple sources of data. Driving, for example, requires you to be aware of traffic signals, other cars, pedestrians, weather conditions, etc., and to use the information to make ongoing, rapid-fire decisions.

MS and cognition
Neuropsychologist John DeLuca, PhD, vice president for research at the Kessler Foundation Research Center, says an overall slowing of processing speed caused by MS is one mechanism that can lead to cognitive dysfunction. “If you’re accustomed to processing everything quickly, like a state-of-the-art computer, and now your speed becomes more like an old 286 processor, it’s going to take a lot longer to get the same answer.”

Dr. DeLuca emphasizes that cognitive dysfunction in people with MS does not necessarily translate into impaired intelligence. In fact, cognitive changes may go unnoticed by others. “If you’re used to functioning highly, even subtle cognitive deficits can have a big effect on you,” says Steve Rao, PhD, a neuropsychologist studying cognitive dysfunction at the Mellen Center for Multiple Sclerosis at the Cleveland Clinic.

Facing depression
Cognitive symptoms are sometimes masked or worsened by co-existing problems, such as depression and chronic pain, explains Pavle Repovic, PhD, a neurologist at the Multiple Sclerosis Center of the Swedish Neuroscience Institute in Seattle.

In fact, some people with MS may initially attribute cognitive difficulties to depression, but a good multidisciplinary team can tease out what’s causing them, Dr. LaRocca says. “Depression can be accompanied by slowed thinking, difficulty concentrating and memory lapses. However, these are likely to resolve if and when the depression lifts. Cognitive changes that are a result of neurological changes are likely to progress in severity. Cognition can improve in some cases if the cognitive changes are a result of inflammatory changes associated with an exacerbation.”

Medications used to treat pain in MS can also cause cognitive dysfunction. “Some studies of patients undergoing long-term opioid treatment for chronic pain have shown adverse effects on attention, speed of information processing, working memory and short-term memory,” says Dr. LaRocca. Dr. Repovic adds that some medications commonly prescribed for bladder dysfunction (Ditropan, Detrol, Vesicare and Enablex) can contribute to memory loss, somnolence and confusion, although these effects typically occur more suddenly than when they are MS-related.