LECT 6 MEMORY DISODERS.pptx. .

Memory diseases

1. MEMORY DISODERS

2. Age appropriate Memory Impairment Organic Amnesias: Dementia Psychogenic Amnesias Memory Impairment

3. This demonstrable loss of memory with increasing age has been termed Age-associated memory impairment (AAMI). It is not uncommon for older adults to complain of declining memory: Forgetting names and appointments and misplacing everyday items, such as keys Age-Associated Memory Impairment

4. Studies comparing the objective memory performance in people between the ages of 35 and 44 years and those between the ages of 70 and 74 years has shown: Younger age group had scores up to 50% higher than those in the older group. Memory for non-verbal material seems to be more affected by aging than memory for verbal material, and Delayed recall is affected more than immediate recall. Age-Associated Memory Impairment

5. Perception by the subject of memory loss (e.g. misplacing articles such as keys, spectacles, etc.). Objective evidence of impairment of memory on standardized tests of delayed recall for verbal information. A score of one standard deviation below that of a young adult on tests of memory. Absence of other conditions that may affect memory, including depression and dementia. Criteria for age associated memory impairment

6. Approximately 40% of individuals aged 65 and over show AAMI. A common bedside test is to give a list of 20 words to the subject to study and then ask him or her to recall as many as possible 20 minutes later (delayed recall). The score is compared with standardized scores for the given age. There is considerable individual variation and a subgroup of elderly individuals have memory and cognitive functions are well preserved. Other features of aami

7. The term dementia has been used in two different ways. It has been used to describe a symptom, the gradual, and usually progressive, decline in memory. In the second usage the term dementia is employed to describe a clinical syndrome (as defined in DSM-IV and ICD-10) Dementia is characterized by: marked loss of memory, deterioration in adaptive functioning and, at least one other additional sign of major cognitive deficit (aphasia, agnosia or loss of executive functions). Dementia

8. Dementia consists of a collection of symptoms that imply widespread cerebral damage. The most common cause of this syndrome in individuals over 65 is Alzheimer’s disease (AD), which accounts for approximately two-thirds of all cases of dementia. dementia

9. Agnosia : Inability to understand the importance or significance of sensory stimuli; Aphasia : Any disturbance in the comprehension or expression of language caused by a brain lesion Executive functions: definitions

10. Episodic memory refers to a long term memory which is specific, personally experienced events or episodes from the individuals' past. Procedural memory is a type of implicit memory for sequences/procedures (cycling, skating etc.). Implicit memory is a behavioral, emotional, and perceptual form of memory devoid of the subjective internal experience of recalling, of self, or of past. Semantic memory refers to retrieval of facts from the organized knowledge about the world. Echoic memory refers to sensory auditory memory lasting 3-4 seconds. definitions

11. The earliest sign of AD is loss of memory and the major memory system affected is episodic memory. Storage of information regarding our past experiences, is known as episodic memory. The impairment of episodic memory is evident early in the course of AD and is best demonstrated by tests of delayed recall such as remembering a name and address after 5 to 10 minutes. Loss of remote memory becomes evident next. It begins with difficulties in recall of recent events and proceeds, according to Ribot’s law, to extend to more distant memories. Alzheimer's dementia

12. Semantic memory deals with organized knowledge about the world Shows deterioration early in the course of AD but may not be apparent to the subject or the clinician unless specific tests are carried out. In comparison with marked deficits in LTM, working memory remains remarkably intact even in the later stages of the disease; implicit memory is spared until very late stages of the disease. Alzheimer's dementia

13. In addition to AD, various other disorders can give rise to the syndrome of dementia, most notably vascular and other degenerative pathologies.   The mini-mental state examination (MMSE) is a popular screening and rating tool for dementia. In addition to memory it assesses orientation, praxis and other functions. The Cambridge cognitive function examination (CAMCOG) is a well-established research instrument for the assessment of dementia in elderly people. It assesses a wider range of cognitive functions than memory (attention, abstraction, language, and so on). It is part of a standardized psychiatric assessment sched Alzheimer's dementia

14. The amnesic syndrome has been defined as ‘an abnormal mental state in which memory and learning are affected whereas all other cognitive functions are intact. Cause: herpes encephalitis, severe cerebral hypoxia and thiamine deficiency Amnesic Syndromes

15. Intact short term memory Anterograde amnesia Retrograde amnesia Preserved global intellectual abilities Preserved implicit memory Clinical features

16. Intact short-term memory . Immediate memory is unimpaired. Thus performances on digit span test and other measures of primary memory (requiring the recall of information within a few seconds) are remarkably intact and within normal range. However, performances on these short-term memory tests are sensitive to proactive interference. If, for example, patients are given a second distractive exercise (such as repeating three digits backwards) before recalling the test items, the patients are unable to recall the original items. Clinical features

17. Anterograde amnesia (AA). This refers to the inability to acquire new information. The classical pattern of Anterograde amnesia consists of normal immediate recall as indicated above (e.g. digit span) and impaired delayed recall (e.g. recall three items or an address after five minutes. Because of the inability to learn and retain new information, most patients experience difficulties in remembering recent events such as the ingredients of their last meal, the name of the hospital or, even, the date. Anterograde amnesia

18. Retrograde amnesia (RA). Retrograde amnesia is the inability to retrieve information that had been stored prior to the onset of amnesia. While in amnesic syndrome AA is typical and characteristic and invariably present, RA shows considerable variability both in extent and severity. The degree of RA depends to a large extent on the locus of damage and the past events are better remembered than more recent events ( Ribot’s law). Retrograde amnesia

19. This is a specific form of the amnesic syndrome resulting from nutritional depletion, notably thiamine deficiency. The most common cause of the syndrome is alcohol abuse. The pattern of memory deficit in Korsakoff’s syndrome involves a severe impairment of new learning (Anterograde amnesia) and extensive retrograde loss. Korsakoff’s syndrome.

20. This retrograde memory loss extends back at least 25 to 30 years and includes loss of memory for remote information and autobiographic memory for incidents or events from the patient’s past. These aspects of retrograde memory show a temporal gradient, with relative sparing of the most distant memories Working memory, priming and procedural memory are well preserved. Korsakoff’s syndrome

21. Immediately following head injury many patients (after recovering consciousness) show an impairment of memory for events that occurred previously. The amnesic gap is known as post-traumatic amnesia (PTA) or post-concussion amnesia. PTA is the time between the injury and recovery of normal continuous memory. The length of PTA is considered to be more accurate than the length of coma in predicting recovery of function. The longer the period of PTA the more severe the brain damage and poorer the prognosis for the recovery of functions. Memory Loss in Head Injuries

22. A typical PTA grading system is as follows: PTA less than 1 hour – mild head injury PTA from 1 to 24 hours – moderate head injury PTA longer than 24 hours – severe injury Pta grading system

23. Retrograde amnesia is also common after head injury. RA is the loss of memory for events occurring before the time of injury. Amnesia extends backward in time for a variable period. As memory is regained, RA shows shrinkage and the most remote memories return first. In most cases the amnesic gap is very short, usually lasting one minute or less. It is not a good indicator of prognosis. Retrograde amnesia

24. A specific syndrome termed transient global amnesia (TGA) describes a condition occurring in middle-aged or elderly men in whom there is profound but temporary failure of memory lasting several hours. During the attack the subject is unable to acquire new lasting memories (AA) and, therefore, continues to have a permanent memory gap for the period of attack. Transient Organic Amnesias

25. Psychogenic amnesia are thought to be caused by psychological factors, especially traumatic events, which are unacceptable to the person. There is no actual brain damage and the amnesia recovers over a period of time. Psychogenic Amnesias

26. In clinical practice two types of psychogenic amnesia have been recognized: ‘global’ and ‘situation-specific ’. In Global Amnesia, sometimes known as fugue state, there is sudden loss of all autobiographical memories and knowledge of self and personal identity. This is usually associated with wandering, for which there is an amnesic gap upon recovery. Psychogenic amnesia

27. Global amnesia usually follows exposure to some form of psychological trauma. Often such patients report having made trips over a period of hours but do not recall what happened during that time. Psychogenic amnesia

28. Patients are usually unaware of the memory disturbance. Usually memory recovery is complete after few hours or days. Situation-specific amnesia may arise in states of extreme arousal including committing an offence, being the victim of an offence or of child sexual abuse. It may also occur in post-traumatic disorder. Psychogenic amnesia

29. Immediate or STM is tested by recall of information seconds after its presentation. Digit span is the commonest test of auditory, verbal short-term or working memory. In clinical practice, both the forward digit span and the backward digit span are measured. TESTS OF MEMORY  

30. The subject is given a string of digits beginning with two digits and asked to repeat it immediately. The score is the longest series correctly repeated. For reverse digit span, exactly the same method is used except that the subject is asked to repeat the digits in the reverse order. The normal range of digits forwards is 6 ± 1 and for reverse digit span it is 5 ± 1. An example is as follows: 4-9, 6-3-2, 6-4-3-9, 7-2-6-8, 4-2-7-3-1, 7-5-8-3-6, 6-1-9-4-7-3, 5-9-1-7-4-2-3, 5-8-1-9-2-6-4-7-8. Digit span test

31. Recent memory can be tested informally by asking patients to recall very recent events such as: how they came to the clinic or hospital, their last meal, or events that may have happened that day. Tests of Recent Memory

32. Recall of three items and progressing on to more complex material. These are tests of Anterograde amnesia and new learning. The three word learning test, where the subject is read out (and shown) three items (e.g. watch, pen, desk) and asked to recall them five minutes later, is used with patients with severe memory loss. Tests of recent memory

33. The commonest test of recent memory is the name and address recall test. This consists of seven items such as “Joseph Phiri, L2021, Paseli Road, Northmead. Here the subject is read a short story from the Wechsler memory scale (WMS) containing 25 elements and both immediate and delayed recall (after an interval of 30 minutes) is tested. Tests of recent memory

34. Non-verbal memory: M ay be tested by the getting subjects to reproduce a geometric shape. One such test is the Rey- Osterrieth complex figure test. This consists of complex geometric figure that the subject is first asked to copy and then to draw from memory after an interval of 30 minutes. Tests of non-verbal memory

35. Recall is impaired in patients with amnesic syndrome, selective and those with mild AD. Remote or retrograde memory may be assessed from questioning the person about a variety of past events from the preceding months, years or decades. Ask about public events, news items and famous events from various past eras. Tests of remote memory

36. Human immunodeficiency virus (HIV) enters the central nervous system (CNS) early in the course of the infection and causes several important CNS conditions over the course of the disease, such as HIV encephalopathy and AIDS dementia complex Aids-dementia complex

37. In 1986, the term AIDS dementia complex (ADC) was introduced to describe a unique constellation of neurobehavioral findings. Prior to the advent of highly active antiretroviral therapy (HAART), dementia was a common source of morbidity and mortality in HIV-infected patients. It was usually observed in the late stages of acquired immunodeficiency syndrome (AIDS), when CD4 + lymphocyte counts fall below 200 cells/ mL , and was seen in up to 50% of patients prior to their deaths history

38. ADC, also known as HIV-associated dementia complex (HAD) , is considered a single entity with a broad and varied spectrum of clinical manifestations and severit . ADC is characterized by cognitive, motor, and behavioral features in adults, usually those with advanced AIDS. With the advent of HAART, a less severe dysfunction, minor cognitive motor disorder (MCMD), has become more common than ADC. history

39.  The risk of severe neurocognitive disorders in patients with HIV is 1 in 1000; patients who are not receiving highly active antiretroviral therapy (HAART) and who have a low CD4 + lymphocyte count are at particular risk. In 4-15% of AIDS dementia complex (ADC) patients, ADC is the presenting clinical manifestation of HIV disease epidemiology

40. The annual incidence of HIV dementia in the Western world prior to HAART was 7%, with a cumulative risk of 5-20%. With HAART, the incidence of HIV dementia started declining, but it has begun to increase again incidence

41. In a study of patients with HIV in a Ugandan clinic, the prevalence of ADC was 31%. If extrapolated to sub-Saharan Africa (26 million people with HIV out of 40.3 million people infected worldwide), ADC would be the most important cause of dementia in persons younger than 40 years. The incidence of AIDS dementia is low when access to health care is good; risk factors include non-use of HAART and low CD4 + counts. [28] Incidence in sub saharan africa

42. AIDS dementia complex (ADC) has a variable progression. Without treatment, the disease typically has a rapid progression over a few months, with a mean survival rate of 3-6 months for patients with AIDS who have untreated ADC. As a result of HAART, however, the survival rate increased from 5 months in 1993-94 to 38.5 months in the 1996-2000 period. Cognitive improvement is observed in patients with ADC after the initiation of HAART prognosis

43. Lower educational levels Older age Lower CD4 + counts and higher HIV RNA levels Decreased hemoglobin level Reduced platelet count Thrush Low body mass index More constitutional symptoms Hepatitis C virus co-infection Poorer prognosis

44. Educate the patient at an early stage, and discuss future medicolegal implications of dementia. The patient should be strongly encouraged to prepare a living will or to assign power of attorney. Educate patients and families about the persistent dangers of the transmission of HIV management

45. HIV dementia is a multifaceted problem, and caregivers should know about the complications, including psychiatric complications. Often, friends and family need counseling and support to deal with this chronic and difficult condition management

46. Currently, highly active antiretroviral therapy (HAART) is the cornerstone of treatment for HIV-related cognitive disorders. Aggressive early treatment of patients with HIV disease with antiviral medications and early suppression of viral replication prevents most of the devastating consequences of HIV dementia Early and aggressive treatment of HIV infection decreases the rate of dementia from greater than 50% to 10% management

47. Multiple studies have shown that patients on HAART show partial reversals of neuropsychological deficits and significant improvement, which is sustained, whereas patients not on HAART steadily decline. HAART protects against and induces remission and decreases the incidence of AIDS dementia complex (ADC) and HIV-associated progressive encephalopathy (HPE). Early and continuous viral suppression with HAART is associated with improved performance on neuropsychological testing. management