Chronic treatment of parkinsonism with levodopa or levodopa/carbidopa is associated with problems that include dyskinesia, on-off phenomena, hallucinosis, and possible loss of therapeutic efficacy. We studied the effects of a period of transient drug withdrawal (drug holiday) in 16 patients who manifested these complications of chronic levodopa therapy. Patients were evaluated daily before, during, and after the period of drug withdrawal. Eleven of the 16 patients exhibited enhanced motor responsiveness after the holiday and required only half of the initial daily dose for improved motor performance. Most levodopa-induced side effects decreased after the holiday. Hallucinosis was ameliorated in all cases. The frequency of on-off phenomena and myoclonus also diminished. Sensitivity to levodopa-induced dyskinesia was not affected by the drug holiday. Because most patients required lower dosage after the holiday, dyskinesias were no longer present. These observations suggest that parkinsonian patients who suffer complications of chronic levodopa therapy may benefit from a period of drug withdrawal.
We studied 55 cases of cerebellar atrophy identified by computerized tomography. Atrophy was determined by subjective assessment and objective measurements (superior cerebellar cistern, fourth ventricle, and brainstem). Different patterns of cerebellar atrophy were related to clinical diagnoses. A high incidence of vermal atrophy was observed in primary cerebellar degeneration and chronic alcoholism. More than half the patients with alcoholism had hemispheral atrophy. Vermal atrophy and enlargement of superior cerebellar cisterns (but not hemispheral atrophy) were associated with carcinomatous cerebellar degeneration. Atrophy caused by chronic phenytoin usage showed a specific pattern of enlargement of the cisterna magna, cerebellopontine angle, and superior cerebellar cisterns. Supratentorial atrophy was increased significantly only in the alcoholics. In general, limb ataxia, dysarthria, and nystagmus were related to hemispheral but not to vermal atrophy.
This review summarizes research techniques that have been applied to the early diagnosis and presymptomatic detection of Huntington's disease. Presently, no one test definitively discriminates between nonaffected persons and carriers.
Quantitative measurements of delta activity were made in 10 healthy elderly controls and 31 subjects with Alzheimer's disease. Delta activity did not discriminate between the healthy elderly controls and the early mild Alzheimer's disease subjects. However, delta activity was a significantly greater percentage of total EEG power in the moderate-to-advanced Alzheimer's subjects when compared to either the healthy controls or mild Alzheimer subjects. In the T3 and T4 electrodes, delta activity in the moderate-to-advanced Alzheimer subjects was 78.3% and 47.6% higher, respectively, than in control subjects. Furthermore, delta activity was an excellent predictor of dementia severity within the 31 subjects with Alzheimer's disease.
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