Manifestations of Mild Cognitive Impairment: Memory

Memory is central to the entire function of the brain. Memory problems typically occur when the brain processing speed become slower than usual. Slower brain speed is directly linked to a loss of the brain chemical acetylcholine which regulates sensory input and long term memory retrieval. Very few people have naturally high acetylcholine levels which promotes creativity. People with high acetylcholine not only have distinct creative flair but also are intuitive and empathetic as well as with intelligence, strong immediate memory. The trait of intuitiveness is to embrace the intangible part of life through spirituality, literature, art, science, imagination and empathy. Intuitiveness requires a vision of life that’s beyond the sensory type (only be influenced by sensory perceptions. Without acetylcholine, this transformation in reasoning can not happen.

Besides governing brain processing speed, acetylcholine is also the building block for myelin (the substance surrounds neurons to insulate the nervous system similar to coatings of electrical wires). Myelin thickens with use. As myelin increases, it builds neuron connections that make the thinking process faster. The decay of myelin leads to cognitive and memory decline when the messages that brain chemicals carry get disrupted. Without the proper amount of myelin and acetylcholine, the brain can short-circuit.

Levels of acetylcholine naturally decrease with age. Slower brain speed causes fewer memories to be transferred from short-term working memory to long-term storage. The result is that memory traces get lost in the process. The typical symptoms associated with a slowed brain is the general absentmindedness such as can not remember where anything is. Other signs are: unable to visualize once-familiar objects, people, or places, “blank out” when trying to remember, even midway through a sentence or a task. This type of forgetfulness is not equivalent to “memory loss” because as we age, memory is still stored in the brain. The problem resides in the increasing difficulty in retrieving past experience efficiently and accurately. New memory creation is not totally blocked.

Memory loss does progress beyond forgetfulness. The rate of memory deterioration differs among different individuals. Before age of 60, the frequency of unable to recognize places usually is not more than once every few months. If the brain ages faster by additional factors (see post “Causes of Mild cognitive impairment”) than the rest of the body, overall memory decline could occur at earlier ages. As discussed in post “Manifestations of MCI: personality and mood”), Memory loss can worsen those of symptoms associated with early MCI: anxiety, insomnia, and depression. Brain speed peaks at age of 30s. Brain speed loss can begin as early as 30s if the brain is not maintained in a healthy way. Brain speed loses 7-10 milliseconds for each decade. At 50s and beyond, slight brain speed change start to produce noticeable memory deterioration. Severe brain speed loss may lead to dementia.

Memory creation involves four stages – acquisition, consolidation, storage, and retrieval. see post “How Do We Remember: Memory Acquisition, Consolidation And Retrieval” for detail. Different aspects of memory are ruled by one of the each brain chemical systems. Memory deterioration occurs in the order of: verbal memory issue, visual memory problem, immediate memory loss, and working memory impairment. The temporal lobes which are regulated by GABA, store verbally presented information. Deficits in verbal memory (forget what is heard shortly) increased the risk of progression to Alzheimer’s disease. The occipital lobe store visual perceptions (faces, colors, shapes, designs, surroundings, pictures, symbols). If immediate memory (verbal and visual memory lasting only about 30 seconds before being transferred to long term memory) falters, new information can not be absorbed. Immediate memory (or short term memory) are briefly stored in the parietal lobes which are regulated by acetylcholine. Working memory is the most important form of memory (see post “What Is Working Memory? The Effect of Aging”). This is the memory process that retain new information as well as connect it to information already learned. It determines thinking, abstract reasoning, problem solving and complex cognitive capacity. The frontal lobes which are regulated by dopamine, handles working memory which is critical to executive function. Long term memory correlates working memory. Working memory is the last to deteriorate, making it undetected while other domains of memory starting to show problems.

Memory deterioration of MCI begins with problems in understanding visual images and spatial relationships. This is shown by the changes in vision – difficulty determining color and contrast, difficulty judging distance, difficulty reading, inability to recognize faces in photographs. When four or more of the symptoms occurs an ophthalmologist should be seen immediately and the “A 7- Step Action Plan For Preventing And Treating Memory Loss” may be followed. Day to day activities also start to show signs of memory problems associated with MCI. These symptoms include:

  • consistent problems recalling recent events
  • constantly ask for information to be repeated
  • difficulty completing tasks used to be done effortlessly (household tasks, financial tasks)
  • difficulty remembering short list of items, appointments, birthdays
  • difficulty getting form one place to another, finding familiar streets or location previously been to
  • excessive use of reminder notes or to do lists
  • forgetting month, years
  • forgetting recently learned information
  • misplacing common items daily
  • reduced interest in hobbies/activities
  • trouble learning how to use a new tool, appliance or electronic machine

Memory is influenced by perception, feeling and experience. Different people being exposed to the same event, may describe the event detail differently. As we age, events of long ago could be retrieved (remembered) differently. The answer could vary significantly if a person is being asked to recall an earlier year event at 50s and 70s. This post provides the general rules for enhancing memory “How To Improve Memory – General Principles“.  Memory loss is reversible. “A 7- Step Action Plan For Preventing And Treating Memory Loss” is the protocol for overall brain health and for how to maintain a 30 year-old-brain for the rest of the life. All components of memory can be enhanced. Memory is not the only cognitive problems associated with MCI. A closely related memory issue is attention. (see next post “Manifestations of Mild Cognitive Impairment Attention” ).

Reference: book by Eric R. Braverman, MD.

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