Sensation and Perceptions in Alzheimer’s
Name of the Student
Alzheimer’s disease is defined as a chronic neurodegenerative disease which leads to progressive loss of short term memory and eventually long term memory. Individuals with Alzheimer’s cannot recollect recent events or learning. The perceptions of individuals include rapid swing in moods, loss of motivation, impaired speech and cognitive disorientation. Alzheimer’s disease occurs mainly in the age group between 40 years and 60 years. The most accepted hypothesis neurodegeneration is the “Beta Amyloidal Hypothesis”. The memory pathway includes connections of neurons. These neurons act as relay centers for learned events. Accumulation of beta-amyloidal proteins causes degeneration of these neurons, leading to an inability of forming short term memory. The perceptions and sensations of individuals related to Alzheimer’s depend upon the stage of Alzheimer’s. Alzheimer’s is divided into four stages. The first stage is called the pre-Alzheimer’s period. It’s marked by ageing effects on memory, but there are no neurodegenerative episodes. The sensations include occasional forgetfulness. The second stage is called the early stage of Alzheimer’s. It is marked by non-remembrance of episodes of forgetfulness. During this stage, the individual often forgets names of family members and close friends. The next stage is known as the middle stage of Alzheimer’s. The individual is challenged with greater difficulty in remembering learned responses, even through facilitation. The final stage is referred as the late stage of Alzheimer’s. In this condition the individual is unable to think and cannot construct thoughts. This leads to disoriented and abusive speech and inculcates a repetitive behavior. Daily living activities are fully compromised and the person relies on caregiving only.
Keywords: Sensation, Perception, Alzheimer’s
Sensation and Perceptions in Alzheimer’s
Alzheimer’s disease is defined as a chronic neurodegenerative disease which leads to momentary loss of memory. 60% to 70% of all cases of dementia are believed to be caused by Alzheimer’s. The disease progresses over time and worsens. The major problem in persons suffering from this disease is the loss of short term memory. Individuals with Alzheimer’s cannot recollect recent events or learning. The perceptions of individuals include rapid swing in moods, loss of motivation, impaired speech and cognitive disorientation. Dementia indicates a loss of memory formation due to age-related factors (Querfurth & LaFerla, 2010).
However, although Alzheimer’s present with the same type of symptoms it can initiate at any age and the most vulnerable age group is from 40 years to 60 years. Since, an individual cannot form short-term memory, his or her interactions with the society and the immediate environment deteriorate. These individual withdraw themselves from societal relations. The physiological functions gradually deteriorate which may lead to death, during the middle ages. Alzheimer’s may be caused due to a variety of factors. These may include genetic factors or biochemical factors. The most accepted hypothesis for Alzheimer is the “Beta Amyloidal Hypothesis” (Ballard, Gauthier & Corbet, 2011).
To understand the perception of individuals with Alzheimer’s, the organic cause should be understood. A person suffering from Alzheimer’s cannot recollect recently learned events. This means these individuals are unable to form short-term memory. Memory is a process of retrieving learned events, thoughts or incidences. There are two types of memories; Short term and long term memory. Short-term memory involves recollection of recent events, while long-term memory involves recollecting past events which were learned or presented to the individual. For forming new memories, the short term memory must become potentiated (long-term potentiation). At least the events should reach the prefrontal cortex through the hippocampus (Ballard et al., 2011).
However, in Alzheimer’s the neuronal pathway to the memory forming centers are damaged and hence, recent events are not learnt and hence cannot be retrieved. The memory pathway includes connections of neurons which are relayed through the hypothalamus, hippocampus and pre-frontal cortex. The specific damage occurs in the Nucleus Basalis of Meynert. These neurons act as relay centers of learned incidences to hippocampus for the formation of memory. However, there are beta-amyloidal proteins which are secreted from these neurons and entangle them. This causes degeneration of these neurons, leading to the inability of forming short term memory. The neurons are cholinergic, which means they secrete acetylcholine as a neurotransmitter for passing information to CA1 region of the hippocampus (Querfurth & Laferla, 2010).
Thus, the neurophysiology of memory loss and perception of forgetfulness is justified. However, there are other symptoms which are exhibited by individuals with Alzheimer’s. These symptoms and perceptions are also related to the organic cause of the disease. The perceptions and sensations of individuals related to Alzheimer’s depend upon the stage of Alzheimer’s. Alzheimer’s is divided into four stages. The first stage is called the pre-Alzheimer’s period. It’s marked by ageing effects on memory, but there are no neurodegenerative episodes related to Alzheimer’s (Ballard et al., 2011). The sensations related to this stage includes occasional forgetfulness, cannot recollect actions or deeds (for example, misplacing things), minor loss of short term memory (since, short term memory may be revived by facilitator cues), however the exact recollection of events are lacking and sporadic association between the sequential happening of an event could be narrated by the individual (Querfurth & Laferla, 2010).
The second stage is called the early stage of Alzheimer’s. It is actually the phase where a person becomes confirmed of Alzheimer’s disease. This phase is marked by non-remembrance of episodes of forgetfulness (which means facilitator cues are unable to trigger the response of STM). In this stage, the individual often forgets names of family members and close friends. The next stage is known as the middle stage of Alzheimer’s. The individual is challenged with greater difficulty in remembering learned responses, even through facilitation. Thus, in this stage the individual has real problems in forming recent memories (recently earned events). Individuals are often confused, and suffer from lack of sleep or insomnia (Mendez, 2012).
The final stage is referred as the late stage of Alzheimer’s. In this condition the individual is unable to think and cannot construct thoughts. This leads to disoriented speech and inculcates a repetitive behavior. Since, he or she cannot recollect events; they perceive others also cannot remember thoughts. Thus the repetitive behavior exhibited them towards others, is actually a self-reflection and self-feedback on owns disability. The individual uses abusive languages, becomes anxious and even erratic. The mood swings are very drastic. The perceptions and sensations discussed above pivots around the memory pathway (Mendez, 2012).
Since, the memory pathway consists of various structures related to the limbic system; it is possible to incur such emotional outbursts and body language. The most important structure is the hippocampus and amygdala. Hence, when neurodegenerative changes occur, the circuits to these structures are also expected to be compromised. This leads to abusive episodes or periods of sleep disturbances. Moreover, the cognition functions are also compromised, as a result of such changes (Mendez, 2012).
Possible Explanations for Sensations and Perceptions
Individuals who are suffering from different grades of Alzheimer tend to suffer from a disorientation of speech. Speech is a process which starts with active learning skills. Therefore, any visual or auditory cue must be perceived by the speech centers and oriented with previous memory traces, for an effective and meaningful articulation. Although, such individuals can understand the communication of other persons, but cannot orient his or her communication (articulation), as he or she cannot trace back the reaction of a communication which must have happened in the immediate past. Both oral and written language becomes compromised because the individual is unable to frame any feedback (immediate learning) from such actions. This is coupled with a cognitive deficiency of execution which further aggravates the communication problems. Often such actions lead to abusive actions, which he or she, must not have voluntarily inflicted (Querfurth & Laferla, 2010).
During the stage of pre-Alzheimer, the person is marked by a lack of apathy. This is because he is unable to frame emotional feelings instantly. This is because emotion is also a learned process and unless the emotional cues do not reach the hippocampus region, the reaction (memory) towards an emotional incidence would be lacking. As it is seen during the Pre and Early stages of Alzheimer’s, there is a marked compromise, with daily living activities. The individuals have the poor and altered the perception of smell and taste. Further, the execution and motor functions start to depreciate. Attentiveness, alertness, planning functions and flexibility in day to day activities starts to decrease. This is because all the execution functions require learning to be consulted with long-term memory stores, which starts to decrease due to damage to the neuronal pathways. Mild cognitive impairment is associated with individuals in the pre and early stage of dementia (Mendez, 2012).
The major reason for a loss in cognitive functions is due to the loss of implicit memory. Implicit memory is the memory associated with non-declarative learning. Therefore, the body reflexes or habits which were an integral part of an individual become challenged, due to the loss in memory pathways. Individuals often seek assistance in they’re daily living to aid them in their execution functions and a better understanding of their thoughts, rather than their executed actions. During the advanced stages of Alzheimer, the person becomes prone to falls and cannot recollect close relatives. This is due to the greater progression of neuronal damage and neither can they relate place or persons. At this stage, the long-term memory starts to become damaged (Mendez, 2012).
In the advanced stages, an individual’s behavioral and neuropsychiatric actions impose challenges, not only on the individual, but also for his or her family members. The behavioral manifestations are irritation in actions, outbursts and aggressions without any specific cause and increased resistance to care giving. Hence, this stage is marked by a lack of control on one’s own behavior. Illusions and delusions are common in this phase of the disease. Urinary incontinence occurs, because there is a loss of voluntary control over urination. Symptoms presented by individuals during the advanced stages of the disease, inflict huge stress upon their family members. In the final stages of the disease, the individual has to rely completely upon the caregiver. Apart from the psychological constraints, the physical constraints of exhaustion and fatigue become more pronounced (Querfurth & Laferla, 2010).
The individuals are confined to bed most of the time. This happens due to fatigue and care provisions to help the individual, for avoiding the risk of injuries. Severe depression is also pronounced during the final stages of Alzheimer. This is because the restriction in daily activities, a marked loss of communication with other members of the family, avoidance by closes relatives, due to fear of retaliation and confined to bed make the individuals prone to major depressive disorders. The symptoms of depression are easily visible through repetitive behavior, prolonged phases of wakefulness and increased sleep, overeating or under eating and non-reflection of happiness or smile in an individual. The expressions are limited to short phrases of communication, which are often indistinct and unrecognizable. The body language of the individual is also diminished to understand his or her healthcare needs. Care giving completely depends upon the instinct and evidence based knowledge of the care provider (Mendez, 2012).
Apart from the psychological constraints during the later stages the individual becomes crippled with physical ailments. As the individual becomes confined to bed, chances of development of pressure ulcers (bed sores) become increased. Since, the individual cannot express himself or herself properly such infections becomes aggravated to cause septicemia (infection of the blood), which becomes detrimental to the life of the individual (Mendez, 2012). Hence, the care providers and family members must understand the living needs of these compromised individuals and exhibit empathy and adequate care, to sustain their daily living activities.
Ballard C, Gauthier S, & Corbett, A. (2011). “Alzheimer’s disease.”. Lancet 377 (9770),
Mendez, M. (2012). “Early-onset Alzheimer’s disease: nonamnestic subtypes and type 2
AD”. Archives of Medical Research 43 (8),677–85
Querfurth, H & LaFerla, F (2010). “Alzheimer’s disease”. The New England Journal of
Medicine 362 (4), 329–44