Archive for the ‘Alzheimer's’ Category

Memory issues Part 1: Is it Alzheimer disease or something else?

Saturday, March 9th, 2013

'Alzheimer's disease', under 'Alzheimer's'A while back I read an article in the Wall Street Journal with the intriguing  title, "Detective Work: The False Alzheimer's Diagnosis." The story was that of a man who developed problems in the memory and movement arena, was treated for Parkinson's and eventually found to have normal pressure hydrocephalus (NPH), a buildup of the cerebrospinal fluid (CSF) that surrounds and helps protect the brain and spinal cord.

Hydrocephalus, sometimes called "water on the brain," can occur at any age, but is more commonly seen in infants and seniors. When it is present in the very young, often due to a birth defect in which the spinal column doesn't close properly, it puts pressure on the brain and skull usually resulting in an abnormally large head and a bulging of the fontanel, the soft area on the top of the baby's head. It's treated, in many cases, by insertion of a shunt, a tube placed in one of the brain's ventricles (these are a communicating set of cavities filled with CSF). The tube has a one-way valve and is tunneled under the skin of the patient and usually empties into the abdomen.

The other age group in which hydrocephalus is seen more commonly is the over 60 age group. But it can certainly happen to younger adults as well.

One morning in 1990, when I was forty-nine, my wife noted I was having considerable difficulty with a particular kind of memory; the ability to recall something that was just told me was impaired. I turned out to have a benign mass in the center of my head (the technical term is a colloid cyst of the third ventricle) and had it removed by a neurosurgeon. Although the pathologist said it was benign, its location in that crucial area could have resulted in major brain damage or even sudden death.

If that were to happen today, it could be removed via endoscopic neurosurgery (an endoscope is a tube, usually flexible, for visualizing the insides of a hollow organ; it typically has one or more channels to enable passage of forceps or scissors). That procedure takes 45 minutes to an hour, is done via a one-inch incision and the patient goes home in one or two days.But, as you can see by clicking this link and then the photos in the article, colloid cysts have fairly large draining veins and they need to be most carefully attended to.

An MRI can guide the neurosurgeon's path

An MRI can guide the neurosurgeon's path

In my case, prior to the advent of the neurosurgical endoscope, the mass was removed the typical old-fashioned way by making several round holes in my skull and then the cyst itself. One of the veins leaked and I had a major seizure in the recovery room. That left me with a good-sized scar; on an MRI it's more of a cavity in the front part of my brain.

The scar impaired my short-term memory. I've managed to compensate, writing reminders and keeping a calendar, but I developed an interest in Alzheimer Disease and related memory issues, many of which are age-related and some of which are reversible.

The article on "False Alzheimers," notes that >100 medical conditions can present with memory loss, confusion and personality changes. Medications, or drug-drug interactions should be high on the list of things to rule out. An April 2012 article on autopsy studies of over 900 patients thought to have Alzheimer disease found over a sixth had been misdiagnosed.

The prevailing opinion is that NPH is the cause of five or six percent of all patient felt to have dementia. Adult-onset hydrocephalus is different in many respects from that which happens in the very young. It results from a gradual blockage of the conduits that normally drain CSF. It's not uncommon for the person with NPH to think that their symptoms are typical for the aging process.

But difficulties in focusing your eyes, an unusual series of headaches, personality changes, seizures, leg weakness and/or sudden falls should be investigated; it's wise to see your physician if  any of these occur, especially if there are associated memory problems.

Then there are, as Dr. Daniel Schacter, the former Chair of Harvard's Psychology  Department calls them, "The Seven Sins of Memory ," age-related memory issues that we all will likely encounter as we grow older. Being absent-minded, blocking the retrieval of a piece of information (It's on the tip of my tongue), or not remembering a complex chemical formula you learned for a college freshman course fifty years ago all can be totally normal. His book on the subject book revolves around the theory that "the seven sins of memory" are similar to the proverbial "seven deadly sins," and that if you try to avoid committing these sins, it will help to improve your ability to remember. Schacter, on the other hand, argues that these features of human memory are not necessarily bad, and that they actually serve a useful purpose in memory.

My comment over the years has been, "Whenever I put a fact in the front of my mind, one falls out the back."

So don't assume the worst if you forget something; on the other hand, don't ignore memory problems if they are persistent.

 

 

 

 

Thanks for the Memory: part 2: Dementias

Tuesday, June 19th, 2012

It's on the tip of my tongue

In 1990 I needed neurosurgery. The mass which was removed turned out to be benign, but I had a major post-op bleed and was left with a considerable scar on my right frontal cortex. Up to that point I'd had, as I often said, "the fourth best memory in the family."

Afterwards my brain worked well enough. But I had considerable problems moving information from short-term to long-term memory. So when I bought the Harvard Medical School booklet mentioned in my last post, I was intrigued by the research that has been done on the subject and how it applied to me and to others, especially as we age.

Most of us worry about dementia; the Aging, Demographics and Memory Study figures, published in 2007 looking at people 71 or older, estimated there were 3.9 million people with dementia in the US in 2002. Of that group, 2.4 million had Alzheimer's disease. The crucial factor, I thought, was the prevalence, the total number living with a disease, went up with age from 5% of people in the 71 to 79 year old group to 37.4% in those 90 and above. And there are lots more of us living to that age than before.

It's become clear that having a stroke, what used to be termed a "cerebrovascular accident" (CVA), is another major route for developing dementia. A 2010 study in the journal Stroke describes dementia associated with "first-ever stroke" in a French city of 150,000 inhabitants over a 24-year period. Out of nearly 4,000 patents suffering a CVA, 20.4% had dementia. Risk factors for the outcome included age, diabetes, prior heart attack, and atrial fibrillation (an irregular heart rhythm associated with a risk of emboli, blood clots that can be dislodged, travel to the brain and clog an artery).

These figures clearly included those with new-onset dementia, but, because of the study's design, didn't exclude those who may have had the problem prior to their stroke. Nonetheless a history of stroke nearly doubles the prevalence of dementia in people over 65.

Another group with an increased incidence of neurocognitive (thinking/memory) issues includes the roughly 40 million infected with HIV. At least 30% of that group have associated brain function impairment ranging from minor or mild symptoms to full-fledged dementia. With the newer anti-retroviral drug treatments, the incidence (new cases) of HIV-associated dementia (HAD) has markedly decreased, although with people living longer with the virus, overall there are more HAD patients.

There is a roadblock between the circulation and the brain itself, the blood-brain barrier (BBB), which serves, in usual circumstances, to prevent microbes from invading the central nervous system. The human immunodeficiency virus can penetrate the BBB in several ways: one of which is by hitching a ride inside one kind of immune cells called monocytes. This is termed a "Trojan Horse" method.

Another disease, affecting 1.3 million Americans, is termed Lewy Body Dementia (LBD). It's closely associated with the dementia seen in Parkinson's disease. Both have deposits of an abnormal protein that causes difficulties in brain function. In LBD these proteins are found in several areas of the brain; with Parkinson's they are more localized.

Let's get the right pill to help, not hinder

So why is it important to know what kind of dementia a person has?

Some types respond poorly to medications that may help other forms, at least to a limited extent. And LBD patients may be helped by meds that offer less benefit to Alzheimer patients.

It's not always easy, but an experienced neurologist can often sort out which person has which disease.