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Intelligence and Neurological Conditions

April 29th, 2013 No comments

Intelligence is an interesting concept. We have tests that measure what we call intelligence but such tests are limited and culture-centric (not that that is necessarily a negative thing). However, for the sake of discussion I will operationally define aptitude (i.e., intelligence) as Intelligence Quotient so as to have a standard metric as foundation for this post.

I spend time assessing people’s memory and thinking abilities. I almost always try to get some measure of baseline aptitude either by estimating it (e.g., years of education, vocabulary knowledge, word reading ability) or by formally measuring via an intelligence test. Granted, this has limitations but it allows me to estimate how well an individual’s brain should function across multiple domains of thinking (e.g., problem-solving, reasoning, memory, language, and so forth). In other words, the higher a person’s general aptitude (abilities), the better he generally will do across most cognitive domains barring brain insult. This is certainly not a rule codified in stone and in triplicate but it serves as a rubric to follow.

Intelligence as measured by IQ is generally quite stable across the lifespan but can improve modestly with  diligence in informal or formal education. Intelligence as denoted by IQ can also decrease modestly if people are intellectually inactive, although such declines are slight. What can happen though is as brains age or if damaged by a pathological process or an injury, components of IQ can decrease. My primary clinical and research focus is in understanding how brains and cognition change in old age – both naturally and in the presence of neurological (brain) insult. Remarkably, the measures we use for intelligence tend to be rather insensitive to aging and even neurological insult, at least some of the components of intelligence are generally insensitive to brain insult. However, this leads to one area where our conceptualization of intelligence as IQ starts to break down.

As they age, the brains of people almost universally slow down. Wear and tear on the brain over decades of life affects how well and quickly we can think. Blood, which is essential for life and for the functioning of the brain, happens to be toxic to brain cells. Sometimes the protections in the brain that keep blood far enough from brain cells (neurons) to protect them but near enough to feed and maintain brain cells start to break down over time. This can injure the brain and start to reduce how well the brain works, even lowering IQ. Now, does that mean that a person’s intelligence decreases? If IQ = intelligence, then yes, it does. Contrary to how I operationalized intelligence earlier, intelligence is not synonymous with IQ. IQ can be a useful concept but it is far from perfect, particularly if by using it one argues that someone is less intelligent simply because his head was injured in an accident or because she developed dementia or suffered a stroke.

This is an area that demonstrates the limitations of our current research and clinical conceptualizations of intelligence. However, understanding how IQ changes over time and how it is affected by neurological conditions is important information to have, as it can help localize areas of pathology.

Mad Cow And Alzheimer’s Have Surprising Link : NPR

February 26th, 2009 No comments

Mad Cow And Alzheimer’s Have Surprising Link : NPR. If this research showing a link between prion proteins and the deleterious effects of beta-amyloid plaques in rat brains holds true in humans, it has huge implications for finding a cure for Alzheimer’s disease. That would be as big as the polio vaccine or eradicating small pox. This is some research that is worth watching closely.

Volunteering as Therapy for Individuals with Dementia of the Alzheimer’s Type

July 16th, 2007 1 comment

The following post is a lengthy exposition on a possible link between volunteering and Alzheimer’s disease. This post is more social psychology then neuroscience (actually, it has very little to do with neuroscience). I am not asserting that volunteering can be a useful therapy for someone with Alzheimer’s disease, rather I am making the case that there is enough evidence for research to be conducted along those lines. In other words, I see a need for someone to research whether or not volunteering is beneficial for people with Alzheimer’s disease.

Alzheimer’s disease (AD) is a serious condition that affects an estimated four million people in the United States. Most of these people are over the age 65, since the risk of developing AD increases with age. It is also estimated that there are currently over 400 thousand new cases of AD each year in the United States alone (Rodgers, 2002). The prevalence rate of Dementia of the Alzheimer’s Type (DAT), according to the Diagnostic and statistical manual of mental disorders–fourth edition (DSM-IV) is “between 2% and 4% of the population over the age 65 years…[and] the prevalence increases with increasing age, particularly after age 75 years” (American Psychological Association [APA], 1994). (In this post, the terms AD and DAT are used as interchange terms, even though DAT is the Axis I code and AD is the Axis III code in the DSM–IV. This is done because most articles about Alzheimer’s use the term “AD” in lieu of “DAT”). For this post, I will first give the DSM-IV diagnostic criteria for DAT. Then, I will discuss the effects of that volunteering has on older people. I will also provide some background theories about why volunteering has the effects that it does. Next, I will make the connection between AD and voluntarism.

DSM-IV Criteria for DAT

There are six main criteria associated with DAT as found in the DSM-IV. The first is:

“The development of multiple cognitive deficits manifested by both (1) memory impairment (impaired ability to learn new information or to recall previously learned information) [and] (2) one (or more) of the following cognitive disturbances: (a) aphasia (language disturbance), (b) apraxia (impaired ability to carry out motor activities despite intact motor function), (c) agnosia (failure to recognize or identify objects despite intact sensory function), (d) disturbance in executive functioning (i.e., planning, organizing, sequencing, abstracting)” (APA, 1994, p. 142).

Read more…

By 2050, worldwide Alzheimer’s cases may quadruple

June 12th, 2007 No comments

From a recent AP news article: “More than 26 million people worldwide have Alzheimer’s disease, and a new forecast says the number will quadruple by 2050. At that rate, one in 85 people will have the brain-destroying disease in 40 years, researchers from Johns Hopkins University conclude.”

It’s had to imagine the costs on society that this will have – 100 million people in the world with Alzheimer’s! It could be devastating both emotionally and financially.Old Man

Alzheimer’s disease (AD) has an estimated yearly associated cost in the United States of $100 million (US). This cost results from direct care, lost wages of care takers, and so forth. AD is turning into quite an epidemic; hopefully researchers can find a cure for this debilitating disease. One book that I’ve enjoyed tremendously about AD is Learning to Speak Alzheimer’s by Joanne Coste (available from Amazon for around $10 US). It is easy to read and written with great compassion by someone who truly does understand Alzheimer’s disease.

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War-related traumatic brain injuries

June 9th, 2007 No comments

An article in the most recent Monitor on Psychology (published by the American Psychological Association) [here's a link to the article that is accessible for free online: Link) reminded me of something one of my professors in graduate school told our class a couple years ago. He is a clinical neuropsychologist who occasionally does some consulting for the military. After he returned from a consultation with the military he told us that between the war in Afghanistan and the Iraq war there had been 18,000 central nervous system (brain and spinal cord) injuries of soldiers and contract employees serving in those two countries. The majority of the injuries were minor and many were not combat related but there are still thousands of people with moderate to severe CNS injuries that were acquired in war zones. Quoting from the Monitor article:

"Psychologists, particularly neuropsychologists, are stepping in to assess the damage, help patients learn new strategies to compensate while their brains recover, and raise public awareness of the increasing number of servicemen and women with TBIs. In fact, 1,977 service members were treated for them at Defense and Veterans Brain Injury Center (DVBIC) sites from January 2003 to February 2007."Soldier Helmet

One reason for high rates of traumatic brain injury in the Iraq (and Afghanistan) war(s) is the improved (compared to previous wars) body armor and other life-saving devices. The downside to fewer fatalities is that there are higher rates of people with severe injuries who survive. The mild TBI rates are shown to be: "between 10 and 20 percent [in some surveys] of soldiers returning from deployments” (Source). It’s great to have fewer fatalities but TBIs can have profound effects on people. Clinical neuropsychologists can help people with TBIs learn how to best cope with their injuries as well as understand how their lives might be different and what they can do to compensate for any difficulties. Most people with mild to moderate TBIs seem to have complete or nearly complete recoveries; however, those with moderate to severe TBIs may have deficits, many very severe, that last the rest of their lives.

There can be myriad short-term problems associated with TBIs (e.g., mental slowing, memory problems, personality changes, concentration and attentional difficulties, etc.) but there are also long-term ones. Research has shown that a person with a history of multiple TBIs is more likely to get Alzheimer’s Disease in old age (well, the research actually shows that there is an over-representation of people with multiple TBIs in the Alzheimer’s population). There is a great need for clinical neuropsychologists currently and in the future to work with and help all of our war veterans who have acquired brain injuries.

Recent alcohol research

May 28th, 2007 No comments

drinking_woman.jpg

There was an interesting recent news story from Reuters. Researchers at the University of Missouri-Columbia found that, “Young adults who binge drink frequently are more likely to show disadvantageous decision-making patterns than their peers who don’t drink as heavily” (from the news article). You can’t assume that just because drinking and poor decision making are correlated that the drinking causes the poor decisions (because people who are poorer at decision making in general may drink more) but as I like to say, “Correlation does not imply causation but neither does does it deny causation.”

On the other hand, there is some evidence that drinking alcohol might slow down the progression and/or onset of dementia (e.g., Alzheimer’s Disease): Alcohol and dementia article. Again, the study is correlational so firm causations should not be inferred.

These two articles demonstrate that there is still a lot of  uncertainty about the long-term effects of alcohol consumption.

Anosognosia and Dementia

May 7th, 2007 No comments

Anosognosia is a word that means unawareness of functional deficit. It is a common condition in people with Alzheimer’s Disease (AD) – they are not fully aware of their deficits. We can’t state that people with AD never have awareness of their deficits because there is a fair amount of evidence that in the earlier stages of AD there is at least some awareness of memory problems and slowed cognition. The relative anosognosia in AD patients can be contrasted with Parkinson’s patients who are all too aware of their deficits. Theirs is mainly a motoric disorder, which is brought about by neuronal death in the substantia nigra, an area of the brain that produces dopamine (a neurotransmitter). The resting tremors and slowed movements can been extremely frustrating to people with Parkinson’s disease because they are completely aware of their problems.

On Alzheimer’s Disease and other dementias

May 7th, 2007 No comments

There are two general classes of dementias: cortical and subcortical. A cortical dementia is one like Alzheimer’s Disease (AD) where the outer layer (the “bark”) of the brain is first affected. AD typically affects the ventromedial frontal and dorsomedial temporal lobes first. The medial portions of the temporal lobes (e.g., hippocampus and parahippocampal gyrus) are heavily involved in memory processes. So typically with AD we first see atrophy (or volume loss) in those regions; the gray matter (bodies of neurons) die off and the brain shrinks. We are still not entirely sure what causes AD – we know genetics plays a part as do environmental factors such as exercise, nutrition, and education but we don’t know the specific pathology of the disease. AD also is related to swelling to some degree; so an adult who is approaching old age can likely reduce the chances of getting AD simply by taking a “baby aspirin” daily. At the very least it will likely delay the onset and slow down the progression of the disease.

There are also subcortical dementias. These can occur as a result of stroke, Huntington’s disease, or Parkinson’s disease. These types of dementias can occur and worsen rapidly (in the case of strokes) or can be fairly mild initially (as in Parkinson’s-type dementias). Subcortical dementias will over time and in the latest stages of the disease become indistinguishable from AD. Another type of subcortical dementia is Dementia with Lewy Bodies (DLB, or Lewy-body dementia). This is a disease that appears to combine aspects of Parkinson’s, Alzheimer’s, and schizophrenia. People with DLB often have vivid visual hallucinations and other psychoses. It is a terrible disease for the person with it as well as caretakers and family.

Categories: aging, Alzheimer's disease, dementia Tags: