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Query: UMLS:C0233794 (memory impairment)
 7,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The active compound in herbal cannabis, Delta(9)-tetrahydrocannabinol, exerts all of its known central effects through the CB(1) cannabinoid receptor. Research on cannabinoid mechanisms has been facilitated by the availability of selective antagonists acting at CB(1) receptors and the generation of CB(1) receptor knockout mice. Particularly important classes of neurons that express high levels of CB(1) receptors are GABAergic interneurons in hippocampus, amygdala and cerebral cortex, which also contain the neuropeptides cholecystokinin. Activation of CB(1) receptors leads to inhibition of the release of amino acid and monoamine neurotransmitters. The lipid derivatives anandamide and 2-arachidonylglycerol act as endogenous ligands for CB(1) receptors (endocannabinoids). They may act as retrograde synaptic mediators of the phenomena of depolarization-induced suppression of inhibition or excitation in hippocampus and cerebellum. Central effects of cannabinoids include disruption of psychomotor behaviour, short-term memory impairment, intoxication, stimulation of appetite, antinociceptive actions (particularly against pain of neuropathic origin) and anti-emetic effects. Although there are signs of mild cognitive impairment in chronic cannabis users there is little evidence that such impairments are irreversible, or that they are accompanied by drug-induced neuropathology. A proportion of regular users of cannabis develop tolerance and dependence on the drug. Some studies have linked chronic use of cannabis with an increased risk of psychiatric illness, but there is little evidence for any causal link. The potential medical applications of cannabis in the treatment of painful muscle spasms and other symptoms of multiple sclerosis are currently being tested in clinical trials. Medicines based on drugs that enhance the function of endocannabinoids may offer novel therapeutic approaches in the future.
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PMID:Cannabis and the brain. 1276 49

Memory functioning and emotional changes were evaluated in 26 early phase multiple sclerosis (MS) patients, as compared with 24 healthy controls. There were no significant differences between the groups with respect to age, education, verbal intelligence, or general visual information processing abilities. The MS group performed significantly below controls on the recognition of nonsense visual stimuli. On most verbal memory test indicators, the MS group did not perform deficiently, but there emerged a between-group difference at trend level on a measure reflecting sensitivity to proactive inhibition. The MS patients reported emotional changes and increased levels of psychological symptoms in several areas. Memory task performance was not significantly correlated with subjective complaints of memory impairment, depressive symptoms, or degree of physical disability. However, subjective complaints of memory impairment were related to depression.
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PMID:Memory functioning and emotional changes in early phase multiple sclerosis. 1459 May 66

Patients with neurodegenerative diseases that cause mainly subcortical pathology often exhibit impairment when required to recall lists of unrelated words, but their memories are supposedly improved by test procedures that promote retrieval such as recognition or improve the organization of the to-be-remembered materials. Difficulties with floor effects on free recall and ceiling effects on recognition and other methodological concerns raise doubts about the validity of existing studies that tested these ideas. Using the verbal memory subtests of the RBANS, we [Arch. Clin. Neuropsychol. 18 (2003) 509] expressed each patient's performances on Story Memory, List Learning, Story Recall, List Recall, and List Recognition as Z scores relative to his or her age group. Then, the Z scores were subtracted pairwise to test hypotheses about the nature of memory in Parkinson's disease (PD). Contrary to expectation, patients with PD did not show better immediate or delayed recall of stories relative to lists and they did not show better recognition than recall. In the present investigation, the same methodology was used to study verbal memory in multiple sclerosis, a disease that primarily affects subcortical structures. In contrast to previous results for patients with PD, the patients with MS exhibited better recall of stories than of lists and better List Recognition than Recall. Differences in the pathology of entorhinal regions in PD and MS may contribute to the differing patterns of memory impairment of these patients. The results emphasize that most patients with MS with memory impairments have deficits that are relatively mild and potentially remediable.
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PMID:RBANS analysis of verbal memory in multiple sclerosis. 1528 35

The cannabinoid signaling system is composed of cannabinoid (CB) receptors, their endogenous ligands, the endocannabinoids, and the enzymes that produce and inactivate them. It is well known that neurons communicate between each other through this signaling system. Delta 9-tetrahydrocannabinol, the main psychoactive compound of marijuana, interacts with CB receptors, impinging on this communication and inducing profound behavioral effects such as memory impairment and analgesia. Recent evidence suggests that glial cells also express components of the cannabinoid signaling system and marijuana-derived compounds act at CB receptors expressed by glial cells, affecting their functions. This review summarizes this evidence, discusses how glial cells might use the cannabinoid signaling system to communicate with neighboring cells, and argues that nonpsychotropic cannabinoids, both marijuana-derived and synthetic, likely constitute lead compounds for therapy aimed at reducing acute and chronic neuroinflammation, such as occurs in multiple sclerosis.
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PMID:Cannabinoid signaling in glial cells. 1539 Jan 10

We report a 52-year-old woman with primary progressive multiple sclerosis (PPMS) presenting with chronic progressive memory impairment. From a couple of years prior to admission, she had developed impairment of her short-term memory. For example, she forgot her nephew's name, and spoke the same phrases again and again. She also sometimes forgot to turn off her gas stove and forgot things she bought in shops. Moreover, her mental activity gradually decreased and she became apathetic. However, she did not note her memory impairment, and had no hallucinations. She was admitted to our hospital on 20 May, 2003 because donepezil had been ineffective for treating her memory impairment. Neurologically, she showed bilateral horizontal gaze nystagmus, mild limb ataxia on the left and mildly ataxic gait. Neuropsychological examinations showed mildly impaired cognitive function, e.g., MMSE 25/30, WAIS-R full IQ 69 and especially in verbal short memory, which may represent temporal lobe dysfunction. Moreover, Benton's visual memory test revealed marked visual short-term memory impairment, while impaired performance on a Kana picking up test suggested mild to moderate attention impairment, which could have represented frontal lobe dysfunction. Brain MRI showed multiple T2-high plaque lesions close to the bilateral lateral ventricles, and bilateral optic nerve lesions enhanced by gadolinium. Also, spinal cord MRI showed a gadolinium enhanced lesion at Th5 on the left. Cerebral spinal fluid (CSF) examination showed normal cell count and protein level, and undetectable oligoclonal bands (OCB), but an elevated IgG index (1.1, normal < 0.85). Visual evoked potentials (VEPs) showed prolonged P100 latency bilaterally, indicating subclinical optic nerve lesions. She was thus diagnosed as having PPMS according to McDonald's diagnostic criteria for MS. 99mTc Single photon emission computed tomography (SPECT) showed a decreased cerebral blood flow (CBF) in the bilateral frontal and temporal lobes, which was consistent with her clinical features. PPMS patients generally present with chronic progressive spastic paraparesis and/or cerebellar ataxia. Cognitive impairments observed in PPMS are generally thought to be due to white matter lesions, i.e., subcortical dementia. However, some recent reports have shown MS patients with short-term memory impairment (antegrade amnesia) similar to cortical dementias such as Alzheimer's disease (AD). In such MS cases, visual short-term memory impairment seems characteristic of their cognitive impairment compared to AD cases. As well, the present case showed visual memory impairment as evaluated by Benton's memory test. Parietal and frontal lobes are reported to be important for verbal and visual working memory, respectively. Thus, in the present case, decreased CBF in the frontal and temporal lobes, which could have been due to a disconnection between cortices and subcortices caused by the white matter lesions, is consistent with the type of her cognitive dysfunction, i.e., notable visual memory impairment. PPMS may thus be an important disease as a differential diagnosis for chronic progressive dementia. Further neuropsychological and functional imaging studies will be necessary to achieve a better understanding of the mechanisms of cognitive impairment in PPMS.
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PMID:[A case of primary progressive multiple sclerosis with onset of memory impairment]. 1596 Jan 71

Memory impairment is among the most common cognitive deficits in people with multiple sclerosis (MS). To remediate this problem, recent research has evaluated the benefits of self-generated encoding. These nascent investigations reveal that people with MS who have mild memory impairment demonstrate a significant memory benefit from self-generated encoding compared with didactic learning. To extend prior research, the present experiment included MS patients with moderate-severe, rather than just mild, memory impairment. Additionally, the experiment evaluated whether self-generated encoding improves memory for activities of daily living instead of abstract words. Specifically, the experiment determined whether self-generated encoding enhanced memory for names, appointments, and object locations. In agreement with and extending prior research, MS patients remembered more information if it was self-generated rather than didactically presented, and this finding occurred despite moderate-severe memory impairment. Furthermore, compared with didactic encoding, self-generation enhanced recall of activities of daily living. Implications of these findings for cognitive rehabilitation and the nature of memory impairment in MS are discussed.
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PMID:Self-generated learning in people with multiple sclerosis. 1696 45

Previous papers have mainly demonstrated the presence of cognitive impairment in patients with multiple sclerosis (MS), these changes have been traditionally associated with the later stages of the disease. In the current study, a comprehensive neuropsychological battery was administered to 216 relapsing-remitting MS patients with mild clinical disability (EDSS<or=3.5) and to 35 healty controls. The results show the presence of significant memory impairment: learning rate of list of words; reproduction visual memory; and long term verbal memory of texts, and information processing speed. We also observed greeter incidence of depressive symptoms in patients. And a little relation of the cognitive deficits with the clinical variables in these phase of the disease.
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PMID:[Neuropsychology of mildly disabled patients with relapsing-remitting multiple sclerosis]. 1729 14

Working memory impairment is frequently observed in patients with early multiple sclerosis (MS). MRI and functional MRI studies have shown that working memory impairment is mostly due to diffuse white matter (WM) damage affecting the connectivity between distant cortical areas. However, working memory deficits in early MS patients can be either completely or partly masked by compensatory functional plasticity. It seems likely that concomitantly with the WM bundle injury resulting from pathological processes, the functional plasticity present in early MS patients may be accompanied by reactive structural WM plasticity. This structural plasticity may effectively compensate for connectivity disturbances and/or contribute to functional brain reorganization. The diffusion characteristics of WM bundles involved in working memory were assessed here by performing quantitative diffusion tensor imaging (DTI) tractography on 24 patients with early relapsing-remitting MS and 15 healthy control subjects. The DTI tractography findings showed that WM connections constituting the executive system of working memory were structurally impaired (the fractional anisotropy was lower than normal and the mean diffusivity, higher than normal). A significantly larger number of connections between the left and right thalami was concurrently observed in the MS patients than in the control subjects, which suggests that the WM is endowed with reactive structural plasticity.
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PMID:Structure of WM bundles constituting the working memory system in early multiple sclerosis: a quantitative DTI tractography study. 1751 34

Sildenafil is a phosphodiesterase-5 (PDE5) inhibitor and is predominantly used in the treatment of erectile dysfunction. While maintaining an excellent safety and tolerability profile in the management of erectile dysfunction, sildenafil also provides a prolonged benefit in various other diseases. Sildenafil has been shown to have a potential therapeutic efficacy for disorders related to the central nervous system and pulmonary system. In the central nervous system, it exerts its neuroprotective effects in multiple sclerosis and has a significant memory enhancing action. Sildenafil also significantly enhances neurogenesis. Several lines of evidence indicate that targeting PDE5 with sildenafil offers novel strategies in the treatment of age-related memory impairment. Guanylate cyclase/cGMP/protein kinase G pathway or glutamate/nitric oxide/cGMP pathway appears to mediate memory enhancing effects. Some of the positive cognitive features of sildenafil therapy are likely attributable to the mechanisms reviewed here. Sildenafil has been shown to reduce pulmonary hypertension and alleviate pain in animals and humans. The present review primarily focuses on the various pharmacological effects of sildenafil with regard to its influence on the nervous and pulmonary system.
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PMID:Versatile effects of sildenafil: recent pharmacological applications. 1755 93

Memory impairment is especially prominent within the spectrum of cognitive deficits in multiple sclerosis (MS), and a crucial role for hippocampal pathology may therefore be expected in this disease. This study is the first to systematically assess hippocampal demyelination in MS. Hippocampal tissue samples of 19 chronic MS cases and 7 controls with non-neurologic disease were stained immunohistochemically for myelin proteolipid protein. Subsequently, number, location, and size of demyelinated lesions were assessed. Furthermore, the specimens were stained for HLA-DR to investigate microglia/macrophage activity. An unexpectedly high number of lesions (n = 37) was found in 15 of the 19 MS cases. Mixed intrahippocampal-perihippocampal lesions, which were more often found in cases with cognitive decline, were large and did not respect anatomical borders. Moderate microglial activation was frequently observed at the edges of these mixed lesions. Isolated intrahippocampal lesions were also frequently found. These were smaller than the mixed lesions and had a specific anatomical predilection: the cornu ammonis 2 subregion and the hilus of the dentate gyrus were consistently spared. Microglial activation was rare in isolated intrahippocampal lesions. Our results indicate that hippocampal demyelination is frequent and extensive in MS and that anatomical localization, size, and inflammatory activity vary for different lesion types.
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PMID:Extensive hippocampal demyelination in multiple sclerosis. 1780 12


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