AD

  In 1907, Dr. Alois Alzheimer  described the brain of his former patients who died with dementia at age 56.  He found plaques and tangles in her brain tissue.  Alzheimer's disease(A D) is the most common cause of dementia in individuals age 65 and over and affects over 5.4 million people in the United States and sure to increase with the rapidly aging baby boomer population.  This disease is the seventh leading cause of death.  The United States  has an annual cost of $72 billion , involving 10.9 million unpaid caregivers.  A D is the focus of this essay.

The adult weight of a  brain is about 3 pounds; the size of a medium cauliflower; with about 100 billion neurons and about 100 trillion synapses.  From a neurological point of view, A D.  Is progressive, complex and affects many functioning components in the human brain.  Briefly, the pathophysiology of A.  D is found in the "Archaic Brain.;" -  The Limbic System  in which functions of the hippocampus or memory formation,,spatial memory and navigation  are destroyed and  in The Cortex  where white matter connective tracts  are destroyed and produce cognitive impairment .

Specifically, neurons are brain cells that coordinate movement ,perception, sensation, language and thinking . Neurons have three parts-dendrites , cell body and axons.  Dendrites take in  information and axons send out information.  Neurons can have as many 20,000 dendrites and axons  and do one of two things: conduct an electrical charge or don't conduct an electrical charge.  Whether neurons are able to cause each other to excite or inhibit surrounding neurons depends on chemicals that pass between them,that are called neurotransmitters. Acetylcholine is an important chemical messenger that passes between the axon of one neuron and the dendrite of another.  This chemical messenger signals the transmission from nerves to muscles, memory formation  and is notably affected in the condition of A D.

The importance of the Limbic System is well noted.  It is involved in survival oriented mammalian characteristics like homeostatic body mechanisms , sex , drives, emotions, moods, emotional memories, encoding and consolidation of long term factual memories  .It is damaged by  dementia of A. D producing memory and emotional deficits.  Within the Limbic System is found, the Hippocampus.  This encodes and consolidates new short-term declarative or factual memories into long-term memories.  With most people the left hippocampus is involved in verbal language oriented memories while the right hippocampus is involved in nonverbal memories.  A. D damage causes amnestic deficits in encoding, recalling new factual memories producing early memory deficits.

The cortex is the most complex object in the universe.  Within the cerebral cortex , the frontal lobes are enlarged in humans compared to other animals . The frontal lobe is involved in planning ,initiation ,control and feedback changes in all actions; regulates attention and inhibits emotions and impulses; is responsible for integrating facts and emotions to make judgments and decisions including ethical and moral decisions and is the center for abstract conceptual thinking and problem solving . It is the site of short-term memory and the storage site for long-term procedural memories . The frontal lobes are impaired first in dementia and last-in A.D.

There is Short-Term Memory which encodes information into the cortex to hold onto for approximately 30 seconds.  There is also Long-Term Memory which consolidates information into long-term storage so that information can be retrieved at a later time.   The Hippocampus of the limbic system is heavily involved in storing long-term memories and becomes impaired in long-term memory storage and retrieval ( amnesia) and  can become a permanent deficit.

There are two types of long-term declarative memory -  remembering facts and events  held over a long period of time as in telephone numbers, names of people)  The first is Episodic declarative memory  which is for personally experienced events such as what you ate for dinner last night. They are time-based life events in one's autobiographical memory  and  become most disrupted by dementia.  The second is Semantic declarative memory for facts which are not tied to one particular time.  Memories would include your name, kind of car you drive, words of  a language, phone number, arithmetic operations.  It’s a general fund of knowledge . Another type of memory is called Procedural memory and it's the ability to retain and to engage in motor activities such as making coffee, driving a car, playing a sport, sometimes called muscle memory. It's memories that become habits and automatically triggered. There can be  disruptive declarative memory without disrupted procedural memories.  This type of memory impairment is seen in moderate to severe AD.

With this brief overview of A D are a number of symptoms that become progressively worse over time: 1.  Progressive memory impairment-recent facts and remote facts and procedures  2, Time , space, and spatial disorientation 3 Receptive language impairment-aphasia with visual and  auditory comprehension deficits.  4.Anomia or poor object naming, especially parts of objects.  5.  Decreased word finding 6.  Vague statements and impaired abstract and conceptual thinking 7.Acalculia which is impaired arithmetic calculations 8  Visual Agnosia which is impaired object , or facial recognition 9.Apraxia difficulty performing purposeful movements, especially using  household utensils 10. Apractagnosia, which is the inability to use objects correctly.  11.  Personality changes in and out of passivity,withdrawal, hostility, anger 12.  Progressive decreased emotional expression.  13.  Delusions and hallucinations.  14.  Depression or anxiety.

Within this irreversible progressive disorder , the brain cells, the neurons deteriorate with 4 different stages. A brief statement regarding the 4 stages follows . Stage  1.  Mild Confusion State. Independent living becomes gradually affected, requiring  minimal assistance .  Stage 2 .  Mild to Moderate Impairment.  The person is  self-aware and recognizes increasing deficits with the possibility of developing depression and anxiety.  Stage 3 . Moderate Impairment.  The person cannot live independently and requires moderate assistance, such as dressing, housekeeping , cooking . Able to remember  basic identity and family information.  Stage 4 .Severe Impairment  . The person is unaware of present and recent experiences . Memory of personal history impaired.  The person usually knows the names and faces of family members  Stage 5. Very Severe Impairment . Person requires 24 maximum assistance.  Often the person is bedridden and unable to move about independently.  Seizures are possible , general organ system failure, health deterioration with immune suppression, and more infections .

For many Homo sapiens, having a future is extremely important for a wellbeing mental health. A future provides for the potential of hope, achievement, joy, happiness and creativity .  In fact, the film The Bucket List with Jack Nicholson and Morgan Freeman comes to mind.  For others, their future is associated with doom, gloom, despair ,pain and extreme unhappiness.  The devastation  or the absence of hope is not limited to diseases of  Alzheimer’s, ALS, Parkinson's and juvenile diabetes . However, they are examples linked to an untreatable , progressive deterioration of mind and /or body.  For instance, ALS and Parkinson's are similar with loss of muscle control, postural instability, gait problems,and slowness of movement, ;juvenile diabetes with vision impairment, poor circulation, and the severing of  limbs; and A.D. is related  with loss , amnesia, of identity,self , and others in their lifespace  .  This  unconscionable  devastating state also has consequences for loved ones, significant others, and caretakers.  It's not  surprising when individuals in a diseased condition intend to give up  and even take their life.  

References

PS

A hospice nurse was quoted in the October 29, 2023 edition of The New York Times.: "I've never met someone 100 or older who still wants to be alive." However, my good friend Jonathan, in his 60s ,went out one day for a run with his son Atticus.  On that run.  Jonathan trailed behind.  Atticus  headed back on the trail and found his dad sitting on the ground being propped up by the tree without  movement. 

Brain Injury: Alzheimer's, Stroke And Head Trauma.  Institute for Natural Resources.

Understanding Dementia.  Institute for Natural Resources.