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Cognitive Impairment in MS (PART 1: overview, affected processes)
While there are no treatment options yet for cognitive issues in multiple sclerosis, research suggests that exercise (particularly aerobic) and consistent "brain training" are two ways to combat the dreaded cog fog. This is a detailed article, broken down in four parts. - Dave
Posting of the following article has been approved by Dana Organization. www.dana.org
Cognitive Impairment in Multiple Sclerosis
A Forgotten Disability Remembered
By Kristen Rahn, Ph.D., Barbara Slusher, M.B.A., Ph.D., and Adam Kaplin, M.D., Ph.D.
November 30, 2012
Editor’s note: Physicians first noted the presence of cognitive impairment in patients with multiple sclerosis (MS) more than 160 years ago, yet it took clinicians until 2001 to codify a standard test to measure cognitive function. We now know that cognitive impairment occurs in up to 65 percent of people with MS and usually lessens their ability to remember previously learned information. So far, trials of drugs formulated to treat cognitive impairment have failed, but the authors remain optimistic that new approaches to diagnosis and drug development could lead to effective therapies in the future.
Multiple sclerosis (MS) is a disease of the central nervous system (CNS) in which the immune system, normally charged with fighting off invading organisms, attacks the body’s myelin sheaths, the protective insulation that envelops neurons and facilitates high-speed neuronal communication. Without myelin to assist and protect neurons, the brain and spinal cord signals that permit us to interact with our environment malfunction. Neurons in the brain can be compared to the electrical wires of a house. Both are wrapped in protective insulation—neurons in myelin and electrical wires in rubber—to protect the integrity of their structures. In a way similar to how lights flicker when there is erratic signaling or fail to turn on when their wires rust and break, MS patients often experience weakness, loss of coordination, and neuropathic pain due to erratic neural signaling. They may also experience paralysis when their neurons and myelin sheaths are damaged beyond repair.
Depending on the extent and location of damage in the CNS, patients with MS may experience a wide variety of symptoms. The most commonly reported symptoms at the time of diagnosis are blurred vision, tingling and/or numbness, and loss of coordination. As the disease progresses, usually with a series of acute immune attacks and a late-stage steady march of function loss, patients with MS commonly experience fatigue, spasticity, difficulty walking, and cognitive impairment. Before 1993 there were no approved treatments of MS. Today, eight of the nine FDA-approved disease-modifying treatments are designed to reduce the frequency of clinical exacerbations in MS, and one is approved to improve walking ability. None, however, target the cognitive impairment often seen in people who have MS.
Cognitive Impairment in MS: An Overview
Although Jean-Martin Charcot is credited with providing a comprehensive description of MS, reports of both MS and comorbid cognitive impairment precede Charcot’s 1868 lectures. Dr. Friedrich von Frerichs first cited MS-related cognitive impairment in 1849, 25 years after the disease’s initial clinical description. Despite multiple early accounts of MS as a disease affecting cognition, reports on the incidence of cognitive impairment in patients with MS were mixed over the following century. While some late 19th and early 20th century physicians recognized deterioration of cognitive faculties in more than half of their MS patients, others reported that only two percent of their patients with MS experienced blunted intellectual function.[1]1 Discrepancies in these figures are probably due to the fact that the majority of neurologists did not ask patients with MS about their cognitive function, and those neurologists who did inquire had inconsistent means of measuring cognitive function.
The Minimal Assessment of Cognitive Function in Multiple Sclerosis (MACFIMS) battery—a seven-test, 90-minute assessment of word fluency, visuospatial ability, learning, memory, processing, and executive function (cognitive skills required to unite learning and memory with behavior)—was not established until 2001. The recent development of improved diagnostic tests for cognitive function has allowed researchers to reach a general consensus: Cognitive impairment is a debilitating and widespread comorbidity of MS. Today physicians recognize that MS affects more than 600,000 people in the United States and more than 2 million people worldwide, and 40 to 65 percent of these patients experience some degree of cognitive impairment.2, 3
Cognitive impairment substantially impacts the lives of patients with MS and their families. Half to three-quarters of people with MS are unemployed within 10 years of diagnosis.4 Cognitive impairment is the leading predictor of occupational disability, while physical disability, age, sex, and education contribute less than 15 percent to the likelihood of being employed.5 Patients with impaired cognition participate in social activities less frequently. Cognitive impairment due to MS may also place significant additional strain on the patient’s caregiver, who must help the patient combat intellectual, social, and occupational disabilities.
The Affected Cognitive Processes
Overt dementia in MS is rare. Most cases of cognitive impairment in MS are relatively less severe than those observed in classically dementing neurological disorders, such as Alzheimer’s disease, in which the patient loses memory of previous experiences and is unable to respond properly to environmental stimuli. However, cognitive impairment in MS can be extremely debilitating, with substantial negative impacts on daily living.
While some researchers conclude that patients with MS have trouble initially committing information to memory, the majority find that most patients have some difficulty remembering information learned in the past. In a study of 426 patients with MS, 66 percent of patients had deficits in at least one recall task, while only 14 percent had encoding impairments (difficulties making new memories).6 The encoding difficulties could be due to decreased processing speed or the inability to make sense of incoming information, both of which are very difficult to measure without an extensive battery of neurocognitive tests.
People with MS also frequently experience compromised attention, and performance on tasks requiring sustained attention can reveal deficits in patients with mild to moderate cognitive impairment. Additionally, it might be difficult for a person with MS to remember information required to complete a task if other distractions are present—a considerable impairment in our multitasking society.
Because the amount of CNS damage and the locations of lesions in the brain vary among patients, cognitive impairment is a somewhat heterogeneous comorbidity of MS. However, studying the cognitive facilities most commonly affected in patients with MS can help us gain insight into effective coping strategies and reveal areas of the brain and signaling pathways that might be logical therapeutic targets. This has important implications for managing and compensating for the daily problems that cognitive impairment causes.
PART 2: http://activemsers.wssnoc.net/showthread.php?t=1164
PART 3: http://activemsers.wssnoc.net/showthread.php?t=1165
PART 4: http://activemsers.wssnoc.net/showthread.php?t=1166
Posting of the following article has been approved by Dana Organization. www.dana.org
Cognitive Impairment in Multiple Sclerosis
A Forgotten Disability Remembered
By Kristen Rahn, Ph.D., Barbara Slusher, M.B.A., Ph.D., and Adam Kaplin, M.D., Ph.D.
November 30, 2012
Editor’s note: Physicians first noted the presence of cognitive impairment in patients with multiple sclerosis (MS) more than 160 years ago, yet it took clinicians until 2001 to codify a standard test to measure cognitive function. We now know that cognitive impairment occurs in up to 65 percent of people with MS and usually lessens their ability to remember previously learned information. So far, trials of drugs formulated to treat cognitive impairment have failed, but the authors remain optimistic that new approaches to diagnosis and drug development could lead to effective therapies in the future.
Multiple sclerosis (MS) is a disease of the central nervous system (CNS) in which the immune system, normally charged with fighting off invading organisms, attacks the body’s myelin sheaths, the protective insulation that envelops neurons and facilitates high-speed neuronal communication. Without myelin to assist and protect neurons, the brain and spinal cord signals that permit us to interact with our environment malfunction. Neurons in the brain can be compared to the electrical wires of a house. Both are wrapped in protective insulation—neurons in myelin and electrical wires in rubber—to protect the integrity of their structures. In a way similar to how lights flicker when there is erratic signaling or fail to turn on when their wires rust and break, MS patients often experience weakness, loss of coordination, and neuropathic pain due to erratic neural signaling. They may also experience paralysis when their neurons and myelin sheaths are damaged beyond repair.
Depending on the extent and location of damage in the CNS, patients with MS may experience a wide variety of symptoms. The most commonly reported symptoms at the time of diagnosis are blurred vision, tingling and/or numbness, and loss of coordination. As the disease progresses, usually with a series of acute immune attacks and a late-stage steady march of function loss, patients with MS commonly experience fatigue, spasticity, difficulty walking, and cognitive impairment. Before 1993 there were no approved treatments of MS. Today, eight of the nine FDA-approved disease-modifying treatments are designed to reduce the frequency of clinical exacerbations in MS, and one is approved to improve walking ability. None, however, target the cognitive impairment often seen in people who have MS.
Cognitive Impairment in MS: An Overview
Although Jean-Martin Charcot is credited with providing a comprehensive description of MS, reports of both MS and comorbid cognitive impairment precede Charcot’s 1868 lectures. Dr. Friedrich von Frerichs first cited MS-related cognitive impairment in 1849, 25 years after the disease’s initial clinical description. Despite multiple early accounts of MS as a disease affecting cognition, reports on the incidence of cognitive impairment in patients with MS were mixed over the following century. While some late 19th and early 20th century physicians recognized deterioration of cognitive faculties in more than half of their MS patients, others reported that only two percent of their patients with MS experienced blunted intellectual function.[1]1 Discrepancies in these figures are probably due to the fact that the majority of neurologists did not ask patients with MS about their cognitive function, and those neurologists who did inquire had inconsistent means of measuring cognitive function.
The Minimal Assessment of Cognitive Function in Multiple Sclerosis (MACFIMS) battery—a seven-test, 90-minute assessment of word fluency, visuospatial ability, learning, memory, processing, and executive function (cognitive skills required to unite learning and memory with behavior)—was not established until 2001. The recent development of improved diagnostic tests for cognitive function has allowed researchers to reach a general consensus: Cognitive impairment is a debilitating and widespread comorbidity of MS. Today physicians recognize that MS affects more than 600,000 people in the United States and more than 2 million people worldwide, and 40 to 65 percent of these patients experience some degree of cognitive impairment.2, 3
Cognitive impairment substantially impacts the lives of patients with MS and their families. Half to three-quarters of people with MS are unemployed within 10 years of diagnosis.4 Cognitive impairment is the leading predictor of occupational disability, while physical disability, age, sex, and education contribute less than 15 percent to the likelihood of being employed.5 Patients with impaired cognition participate in social activities less frequently. Cognitive impairment due to MS may also place significant additional strain on the patient’s caregiver, who must help the patient combat intellectual, social, and occupational disabilities.
The Affected Cognitive Processes
Overt dementia in MS is rare. Most cases of cognitive impairment in MS are relatively less severe than those observed in classically dementing neurological disorders, such as Alzheimer’s disease, in which the patient loses memory of previous experiences and is unable to respond properly to environmental stimuli. However, cognitive impairment in MS can be extremely debilitating, with substantial negative impacts on daily living.
While some researchers conclude that patients with MS have trouble initially committing information to memory, the majority find that most patients have some difficulty remembering information learned in the past. In a study of 426 patients with MS, 66 percent of patients had deficits in at least one recall task, while only 14 percent had encoding impairments (difficulties making new memories).6 The encoding difficulties could be due to decreased processing speed or the inability to make sense of incoming information, both of which are very difficult to measure without an extensive battery of neurocognitive tests.
People with MS also frequently experience compromised attention, and performance on tasks requiring sustained attention can reveal deficits in patients with mild to moderate cognitive impairment. Additionally, it might be difficult for a person with MS to remember information required to complete a task if other distractions are present—a considerable impairment in our multitasking society.
Because the amount of CNS damage and the locations of lesions in the brain vary among patients, cognitive impairment is a somewhat heterogeneous comorbidity of MS. However, studying the cognitive facilities most commonly affected in patients with MS can help us gain insight into effective coping strategies and reveal areas of the brain and signaling pathways that might be logical therapeutic targets. This has important implications for managing and compensating for the daily problems that cognitive impairment causes.
PART 2: http://activemsers.wssnoc.net/showthread.php?t=1164
PART 3: http://activemsers.wssnoc.net/showthread.php?t=1165
PART 4: http://activemsers.wssnoc.net/showthread.php?t=1166
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