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This Month in Archives of Neurology
Arch Neurol. 1998;55:285-286.
Brain Biochemical Changes in Myotonic Dystrophy
Cognitive loss in myotonic dystrophy remains to be explained at the biochemical level. Chang et al (SEE ARTICLE) measured specific biochemical changes in the brain using proton magnetic resonance spectroscopy and correlated these changes with the severity of the genetic defect as measured by the number of trinucleotide repeats. Patients with myotonic dystrophy had elevated brain levels of myoinositol, total creatine, and choline-containing compounds compared with findings in control subjects. These biochemical changes directly correlated with the increased number of CTG repeats from leukocytes. Thus, cognitive loss seen in some patients may be correlated with these important new findings.
Suppressing Multiple Sclerosis
Qu et al (SEE ARTICLE) have studied patients with progressive multiple sclerosis by assaying interferon gamma–secreting cells, T suppressor cell function, and lymphocyte proliferative responses using peripheral blood mononuclear cells from patients with multiple sclerosis and control subjects. The authors studied these responses under controlled conditions and also in the presence of interferon beta-1b, all-trans retinoic acid (RA), and the 2 agents together. The use of interferon beta-1b partially restored defective T suppressor cell function and this potentially beneficial action was synergistically potentiated by RA in the cells of multiple sclerosis patients. These studies provide a basis for a trial of interferon beta-1b combined with RA.
The Genetics of Epilepsy
It is not clear whether the genetic influences for generalized and localization-related epilepsies are separate and distinct. Ottman et al (SEE ARTICLE) studied generalized and localization-related epilepsy in first-degree relatives of probands with epilepsy. In parents and siblings, they found that the risk for all types of epilepsy examined was greater if the proband's epilepsy was generalized than if it was localization-related. The final expression of genetic influences on some forms of epilepsy is complex and relates to polygenetic and multifactorial influences.
MRI Scans and Epilepsy
The findings on magnetic resonance imaging (MRI) scans performed outside of epilepsy centers were compared with the observations found on MRI scans interpreted by epilepsy center physicians. McBride et al (SEE ARTICLE) report that conventional neuroimaging studies were poor for diagnosing hippocampal abnormalities in patients with intractable temporal lobe epilepsy. However, using specific temporal lobe protocol MRIs, they found in 32 of 34 outside MRI scans with normal reports that abnormalities were present. Thus, MRI scans need to be read by physicians experienced with the findings common in temporal lobe epilepsy.
Finding Dementia in 7 Minutes
A rapidly administered neurocognitive test appears to be highly sensitive for diagnosing Alzheimer disease, as reported by Solomon et al (SEE ARTICLE) . It provides distinction between patients experiencing cognitive changes of normal aging and those with Alzheimer disease.
Dementia Questionnaire
Nonclinician interviewers administered the dementia questionnaire by telephone to informants familiar with patients who died with either Alzheimer disease, another dementing disorder, other neurologic diseases, or no neurologic disorder. A comparison by Ellis et al (SEE ARTICLE) was made regarding the cognitive function of these individuals with the diagnosis based on neuropathological assessment. The dementia questionnaire was sensitive to the presence of dementia, detected most cases of mild dementia, and was able to discriminate dementia from other neurologic disorders causing functional impairment. The dementia questionnaire was also able to differentiate Alzheimer disease from other dementing disorders. Thus, it appears useful as a clinical research tool.
Cognitive Loss in Parkinsonian Syndromes
Cognitive impairment of a significant degree was found in some patients with progressive supranuclear palsy, multiple system atrophy, and Parkinson disease. The tests that best identified the patient groups compared with normal controls included the sequential tapping test and the ideomotor apraxia tests, which require motor planning and sequence production. As reported by Monza et al (SEE ARTICLE) , cognitive loss in these patients is not well known and these studies provide important new approaches of assessment.
Mental Development in Tuberous Sclerosis
Jozwiak et al (SEE ARTICLE) found that infantile spasms as the presenting type of seizure is a significant risk factor for impaired mental development in patients with tuberous sclerosis complex. This observation provides additional clarification on a complex subject.
Dementia Following Ischemic Stroke
The findings of Desmond et al (SEE ARTICLE) suggest that dementia is associated with early patient attrition, potentially resulting in the underestimation of its frequency and underrecognition of its importance as an outcome of ischemic stroke.
Cognitive Function in Healthy Elders
A stable cognitive performance is present as measured in a series of elderly subjects and can be disinguished clearly in a subset of individuals who subsequently develop a dementing illness, such as Alzheimer disease. As reported by Rubin et al (SEE ARTICLE) , a significant decline in performance is observed in this group of individuals developing dementia, clearly separating them from those experiencing a normal aging process.
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