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Chapter 19 Delirium, Dementia, and Amnestic and Other Cognitive Disorders (Neurocognitive Disorders)

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Presentation on theme: "Chapter 19 Delirium, Dementia, and Amnestic and Other Cognitive Disorders (Neurocognitive Disorders)"— Presentation transcript:

1 Chapter 19 Delirium, Dementia, and Amnestic and Other Cognitive Disorders (Neurocognitive Disorders)

2 Scientific Course of Neurological Disorders Developments in treatment and cures for neurological disorders have been very slow Understanding concussions and persistent postconcussive syndrome DSM-5 changes to terminology and classification of disorders Technological advances contributing to advances in neuropsychology

3 Changing Views of Brain Function and Dysfunction How the brain mediates behaviors – Major methodologies used in this research: Examination of brain function through lesion generation or brain stimulation in animals Studies of patients with localized brain damage Shifting emphasis from points to pathways – Uniting localization and pathways— Luria Key concepts in neuropsychology: Contralateral control, cerebral dominance, equipotentiality versus pluripotentiality, neurotransmitters

4 Description of the Disorder: Neuropathological Considerations Outcomes of brain damage influenced by age, sociocultural status, personality, and most importantly by type of brain damage Accurate assessment of brain damage requires use of appropriate scan (CT versus MRI) Type of brain disorder – Degenerative versus static, reversible versus irreversible, slow versus rapid progression, morbidity

5 Description of the Disorder: Sources of Brain Damage Head trauma – Aftereffects may be temporary (most concussions) or permanent (closed or open head injury) – Nature of the symptoms varies on an individual basis; some make full recovery, but others are limited – Trauma patients may be at greater risk for developing Alzheimer’s disease Brain tumors – Symptoms dependent on tumor classification (malignant versus nonmalignant, glioma versus meningioma) – Symptoms dependent on brain region affected

6 Description of the Disorder: Sources of Brain Damage cont. Brain malformations and early-life brain damage – There is a difference between destruction of function already acquired and destruction of the brain mechanisms needed to acquire that function before it has been developed – Concept of plasticity – Pre- and perinatal influences on brain development

7 Description of the Disorder: Sources of Brain Damage cont. Diseases of the circulatory system – Cerebral arteriosclerosis – Vascular dementia – Aneurysm Degenerative and demyelinating diseases – Common factors: attack the CNS, slowly progressive and incurable, stem from unknown defect in physiology – Alzheimer’s disease Lewy body dementia and Parkinson’s disease – Huntington’s chorea – Multiple sclerosis – Creutzfeldt-Jakob disease

8 Description of the Disorder: Sources of Brain Damage cont. Alcoholism – Development of alcoholism – Wernicke-Korsakoff syndrome Toxic, infectious, and metabolic illnesses – Carbon monoxide poisoning – Phenylketonuria (PKU) – Tay-Sachs disease – Bacterial infections (e.g., encephalitis, meningitis, neurosyphylis) – Viruses

9 Description of the Disorder: Sources of Brain Damage cont. Epilepsy – Characterized by seizures (sudden, abrupt alteration of brain function produced by an excessive, disorganized discharge of neurons) – Generalized seizures Grand mal and petit mal seizures – Partial seizures – Higher probability of significant intellectual deficit when the disorder involves generalized seizures and appears early in life

10 Some Common Syndromes The communicative disorders – Fluent (Wernicke’s) aphasia Speech is fluent, but generally incomprehensible; tendency to substitute incorrect words for correct ones (verbal paraphasia) Primary disturbance involves profoundly impaired auditory comprehension Lesion is generally in the superior gyrus of the left temporal lobe – Nonfluent (Broca’s) aphasia Comprehension is better, but speech is very difficulty and limited. Lesion is in the lower, posterior portion of the left frontal lobe – Lost abilities: alexia (reading), agraphia (writing), and acalculia (difficulties with numbers)

11 Some Common Syndromes cont. Disorders of perception and motility – Agnosias: Difficulty recognizing some class of external objects Classified with regard to modality and verbal or nonverbal content – Neglect: Most dramatic is vision, where the patient may neglect the entire right or left side of the visual world – Apraxias: Basic deficit involves impairment of purposive movement occurring in the absence of paralysis, weakness, or unsteadiness

12 Some Common Syndromes cont. Dementia (Major and Mild Neurocognitive Disorders) – Several types but all involve usually slowly progressive deterioration of intellectual function Deterioration is frequently patterned, typically beginning with loss of memory, and other abilities deteriorating at later stages of the illness Different from intellectual disability because it involves deterioration from a previous higher intellectual level

13 Some Common Syndromes cont. Most common dementia is Alzheimer’s disease – New method to specifically diagnose Alzheimer’s disease in a living patient; previously could only be diagnosed postmortem by examining plaques in the brain – Generally begins with signs of impairment of memory for recent events, followed by deficits in judgment, visual-spatial skills, and language Language difficulty does not resemble aphasia, but involves word-finding difficulties and progressive inability to produce extended and comprehensible narrative speech

14 Some Common Syndromes cont. Vascular dementia – Associated with hypertension and a series of strokes, with the end result being substantial deterioration (not uniform, but stepwise and patchy deterioration) Frontotemporal dementia – Characterized by executive dysfunction; have greater impairment of executive function but relatively better memory and visuoconstructional abilities than Alzheimer’s patients

15 Some Common Syndromes cont. Amnesia – Memory loss is clearly the most outstanding deficit (i.e., dementia patients are often amnesic, but their memory disturbance is embedded in significant generalized impairment of intellectual and communicative abilities) – Brain structures particularly important for memory: limbic system (hippocampus) and certain brainstem structures (mammillary bodies and dorsomedial nucleus of the thalamus)

16 Some Common Syndromes Amnesia – Anterograde versus retrograde Anterograde amnesia is the inability to form new memories from the time of the onset of the illness, whereas retrograde amnesia is the inability to recall events that took place before the onset of the illness Individuals with Korsakoff’s syndrome demonstrate severe retrograde amnesia

17 Alternative Descriptive Systems Not all clinicians or researchers have adopted the neuropsychologically oriented syndrome approach Alternative method is a dimensional approach in which patients are measured on a variety of neuropsychologically relevant dimensions, such as intellectual function, language ability, and memory – Involves profiling the patient along several continuous dimensions and relating that profile to underlying brain mechanisms

18 Epidemiology Depends on the disorder MS: the further from the equator, the greater the prevalence Head injuries occur more frequently in males – Also in individuals of lower SES Huntington’s disease: marker for the gene located on chromosome 4; prevalence: 5 to 7/100,000 Alzheimer’s disease and general health habits

19 Course and Prognosis Vary across disorders Acceleration stages (rate of progression of the disorder) – Steady state, slow, moderate, and rapid Developmental stage (age of onset): perinatal period, early childhood, late childhood and adolescence, early adulthood, middle age, and old age

20 Course and Prognosis cont. Strokes – Onset in middle age; initially rapid progression that slows. – Recovery is common Malignant brain tumors – Those that appear in middle age tend to progress rapidly unless removed Progressive dementias – Generally appear during middle or old age and accelerate moderately or slowly Head trauma – May occur at any age – Rehabilitation aids recovery

21 Familial and Genetic Patterns Huntington’s disease and Down syndrome are genetic disorders Suspected genetic component to Alzheimer’s, though not well understood Cardiovascular health has associated familial factors, as does alcoholism Tay-Sachs disease occurs almost exclusively in Eastern European Jews

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