Sensation And Perception Slideshare

[Lien Kocurek]

Thedocument is a presentation on sensation and perception in psychology. It defines sensation as the simple experience received through the senses, while perception involves higher-level cognitive processing to interpret sensations and derive meaning. It discusses the different types of sensations based on the senses, as well as factors that influence perception like similarity, proximity, and mental sets. The document also distinguishes between illusions, which involve mistaken perceptions but are still related to a real stimulus, and hallucinations, which involve perceiving something without an external stimulus being present.Read less

This document discusses sensation, perception, and extrasensory perception (ESP). It defines sensation as the body's detection of external or internal stimuli, and perception as the interpretation of sensory information. It describes the five traditional senses and their corresponding sense organs and receptors. It also discusses concepts like absolute threshold and pareidolia. The document then explores various forms of ESP like telepathy, precognition, retrocognition, psychokinesis, and mediumship. It provides examples of famous cases of ESP and individuals who demonstrated purported psychic abilities. Finally, it notes criticisms of ESP research, including the lack of replication and reliable methodology.Read less

Sensory-perceptual alteration can be defined as when there is a change in the pattern of sensory stimuli, followed by an abnormal response to such stimuli. Such perceptions could be increased, decreased, or distorted with the patient's hearing, vision, touch sensation, smell, or kinesthetic responses to stimuli. This activity reviews the evaluation and management of sensory-perceptual alterations and highlights the role of the interprofessional team in managing patients with this condition.

Objectives:Identify the etiology of sensory-perceptual alterations.Outline the presentation of a patient with sensory-perceptual alterations.Describe the management considerations for patients with sensory-perceptual alterations.Summarize the importance of collaboration and communication amongst the interprofessional team to enhance the care of patients with sensory-perceptual alterations.Access free multiple choice questions on this topic.

Any alteration in a patient's normal environment can result in stress especially if such alteration is involuntary. Sensory overload occurs when an individual experiences a stimulus that they are unable to manage and process. Usually, the second stimulus is filtered out by selective perception or coping behavior. However, in certain environmental conditions such as the emergency department, or due to specific underlying illnesses such as dementia, sensory overload can occur due to inadequate filtering of stimuli.[2]

Sensory deprivation occurs when an individual receives a stimulus that is reduced or below the threshold of normal. Risk factors to such alterations can be broadly due to acute illnesses, patient factors related to chronic medical conditions, aging, or due to environmental or iatrogenic causes.[3] This typically occurs when the patient is placed in isolation, such as changes in the environment due to hospital admission or admission to isolated wards. While in isolation, there can be a reduction in the quantity and quality of stimuli and restriction of social interaction. Other risk factors that can lead to increased or decreased alteration in the processing of stimuli can be due to hearing impairment, loss of vision, loss of smell or taste, aging, trauma, electrolyte imbalance, seizure disorder, mental health problems, and genetic causes.

Autism spectrum disorder (ASD): Alterations in sensory-dedicated neural circuits, including neuro-molecular and anatomical changes in primary sensory regions of the brain, are responsible for autism-associated sensory symptoms. GABAergic (gamma-aminobutyric acid) signaling is often affected and responsible for these alterations.[4]

Attention deficit hyperactivity disorder (ADHD): The inability to inhibit irrelevant sensory extraneous stimuli leads to sensory overload in ADHD. This occurs due to impaired information processing and faulty perceptual capacity. Individuals with ADHD have a reduced ability to filter intrusive sensory, motor, and/or cognitive information.[5]

Schizophrenia: Altered sensory processing and perceptual inference are responsible for the positive symptoms of schizophrenia.[6][7] Aberrant neurotransmitter signaling in the sensory pathway and abnormal cortical plasticity mechanisms are implicated in the pathology of schizophrenia.[8] One of the core features of both schizophrenia and ASD are dysfunctional face emotion recognition and motion processing.[9]

Sensory processing disorder (SPD): SPD is a neurological condition in children when the brain is unable to process incoming information in an accurate and organized manner resulting in inaccurate processing and judgment of sensory information. Children can experience difficulty with regulating emotions, problems in attention, and adapting responses.[10]

Altered sleep or sleep deprivation can cause delirium leading to sensory and perceptual alterations. The decrease in rapid eye movement (REM) sleep has been ascertained as a possible factor that can cause delirium.[11]

Critically ill patients in the intensive care unit (ICU) are at increased risk of developing delirium. Sensory and altered perceptions can occur due to host factors, acute illness, and environmental factors. Environmental and iatrogenic factors include sleep deprivation, sensory deprivation, immobilization, and social isolation.[3] Lack of quality and adequate sleep are important risk factors for the development of delirium in patients admitted to the ICU. Such changes negatively affect the quality of care provided to the patients.[12]

In certain circumstances (for example infection control), it may become necessary to isolate patients. Contact isolation will have a negative impact on a patient's mood, increasing the risk of depression, anxiety, hostility, and fear. Due to the uncertainty of the situation, the patient may feel that they are losing control within social isolation, thus influencing their mood.[15] Elderly patients with neurocognitive disorders under physical isolation are more prone to develop delirium.[16]

Several of the neurological disorders and syndromes can present with changes in behavior and cognitive function due to altered brain function.[17] These can be due to acute changes related to trauma, metabolic and electrolyte imbalance, medication, infections, or vascular changes. Furthermore, such changes can happen in a slow and insidious fashion due to inherited disorders, neurodegenerative diseases, malignancies, or structural disorders.[17]

Alzheimer's disease: Due to cortical disturbances, sensory visual impairments are a common finding in Alzheimer's disease. This occurs due to the accumulation of neurofibrillary tangles and neuritic plaques in the visual cortical areas leading to cortical degeneration and atrophy. Higher visual abilities are commonly compromised. These include simultanagnosia, problems with visual attention, visual memory, perceiving structure from emotion, object and face perception, visual learning, and reading. Impairment of visual perception in these patients decreases their quality of life and complicates the evaluation of other cognitive deficits.[18][19][20]

Parkinson's disease: The progressive loss of dopaminergic cells in the retina and other areas of the visual system leads to visuoperceptual deficits in patients with Parkinson's disease. This dopamine deficiency in the retina leads to selective spatial-temporal abnormalities in the retinal ganglion cell function. Patients who develop visuoperceptual deficits are at a higher risk for the development of dementia.[18][21]

Seizure disorder: Patients with epilepsy can have perceptual functions with all five senses affected. This results in impaired or occasionally supranormal sensibility. Ictal perceptual experiences are common but interictal function may also be affected. Since epilepsy is a network disease, it can affect neural circuits distant from the seizure focus. This may account for the correlation between sensory modality affected and the underlying epilepsy syndrome. People with temporal lobe epilepsy often experience impairment in olfaction, such as odor discrimination, identification, and recall. Such altered sensation is due to the close association of the olfactory system with the limbic system (which is often implicated in mesial temporal lobe epilepsy). Visual information processing may also be disturbed in occipital lobe epilepsy.[22]

These dysfunctions lead to impairment in visual acuity, contrast sensitivity, color discrimination, motion perception, peripheral visual field sensitivity, temporal sensitivity, and visual speed processing.[18]

Liver failure, renal failure, and acquired immunodeficiency syndrome (AIDS) can cause sensory-perception alterations. Other causes can include hospitalized elderly patients, ventilation-perfusion mismatch, polypharmacy, patients with a terminal illness, post-surgical status, or patients with a high fever.[27]

The prevalence of delirium can range from 3% to 42% during hospital admission.[28] Delirium can be high as 80% in critically ill patients.[29] Such variations depend upon the cause and the host factors. The prevalence of hallucination in the general population has been reported to be as high as 12% and has a significant impact on functional impairment.[30]

The mechanism by which sensory and perceptual alteration can occur can be due to a direct insult to the brain or due to aberrant stress responses.[31] Biochemical derangement, due to an increase in dopamine, cortisol, glutamate, and norepinephrine release, along with decreased cholinergic functions, may cause such changes. Also, changes in increased or decreased serotonin or gamma-aminobutyric acid activity may manifest as different clinical presentations. Age-related changes in neurotransmission and intracellular signaling may also occur and cause alterations. Aberrant stress responses such as acute changes in the environment, trauma, severe illness, and surgery can cause abnormalities and can alter neurotransmitter release leading to sensory and perceptual alterations. Decreased cerebral oxidative metabolism can cause the abnormal release of neurotransmitters leading to cerebral dysfunction. The cellular signaling hypothesis speculates that intraneuronal signal transduction is affected, causing a change in the neurotransmitter production and release leading to altered sensation.

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