Steven J. Huber

Magnetic Resonance Imaging and Clinical Correlates of Intellectual Impairment in Myotonic Dystrophy

Although intellectual impairment is common in patients with myotonic dystrophy, this aspect of the disease has received relatively little research attention. We examined 41 patients with myotonic dystrophy using objective neuropsychological procedures and magnetic resonance imaging. Ten patients (24%) had severe and generalized intellectual dysfunction, while lesser or no cognitive impairment characterized the remaining patients. Degree of intellectual impairment was not related to neuromuscular status or sex. Patients with severe intellectual disturbance had significantly earlier onset of both myotonia and weakness and were more likely to inherit the disease from their mother. Magnetic resonance imaging findings indicated that while degree of cerebral atrophy was not related to severity of intellectual impairment, skull thickness, focal white matter lesions, and anterior temporal lobe abnormalities were significantly more common in patients with severely disturbed intellect. This study reports a number of previously unreported cerebral magnetic resonance imaging findings associated with intellectual impairment in myotonic dystrophy, but the etiology of these changes awaits neuropathologic examination.

The naming disorder of dementia of Alzheimer type

We studied the characteristics of the naming disorder of dementia of the Alzheimer type (DAT) in 20 patients, who were divided on the basis of Mini-Mental State scores into a mild and a moderate-severe group. Our results confirmed the presence of a progressive anomia which was sensitive both to word frequency and to image quality. Although DAT patients as a group made a similar proportion of perceptual-recognition and aphasic errors as did our age and education-matched controls, evidence was obtained that suggested that variations in the character of the anomia exist among individual DAT patients.

Efficacy of alprazolam for essential tremor

The effect of alprazolam on essential tremor was examined by a double-blind, placebo-controlled parallel study of 24 patients. Results indicated that patients treated with alprazolam had significant improvement in tremor. Transient mild fatigue or sedation in 50% of patients was the primary side effect. Alprazolam may provide therapeutic benefit, especially in patients who require only intermittent therapy.

Fluctuations in plasma dopamine level impair memory in Parkinson's disease

We found a causal relationship between variation in plasma dopamine level and memory impairment in Parkinsons disease. If the level of dopamine was changed between the time of original learning and a later time of attempted memory retrieval, memory performance was impaired when compared with a maintenance of similar dopamine levels on both occasions. The absolute level of dopamine did not influence memory performance. Side-effects of levodopa-carbidopa therapy include variation in dopamine level, parkinsonian symptoms, and possibly “sate-dependent” impairment of memory.

Dose‐dependent memory impairment in Parkinson's disease

Variation in plasma dopamine level between the time of original learning and subsequent memory retrieval causes a state-dependent memory impairment in Parkinsons disease. The occurrence of this phenomenon is not related to either progression of disease or duration of therapy, but is more likely to occur with high-dosage levels of levodopa-carbidopa.

Magnetic resonance imaging and clinical correlations in multiple sclerosis

We examined the relationship between magnetic resonance imaging (MRI) cerebral findings and clinical evaluations in 66 patients with clinically definite multiple sclerosis (MS). MRI observations included total number and location of lesions visualized, degree of periventricular involvement, degree of degeneration of the corpus callosum, and extent of generalized parenchymal atrophy. Overall physical disability was evaluated by the Kurtzke Expanded Disability Status Scale (EDSS) and individual symptoms were rated according to the Kurtzke Functional Systems (FS) scale. Our results suggest that MRI brain abnormalities are significantly related to the overall severity of disease, but MRI is not particularly useful to predict the presence or absence of individual symptoms. These findings do suggest that the MRI may provide useful information to monitor clinical progression of patients with MS, but the lesions visualized need not always be symptomatic nor are we sure that all symptomatic lesions, particularly in the spinal cord and optic nerves, will be visualized.

Neuropsychological Similarities in Lateralized Parkinsonism

Parkinsons disease (PD) patients who have left or right predominance of motor symptoms may exhibit cognitive differences. Previous research found greater neuropsychological impairment in patients with both right and left motor predominance, and some found no differences. Variability in overall severity of disease among the patients studied makes evaluation of these reports difficult. We examined the possibility that neuropsychological differences may occur in different stages of disease by comparing patients with mild unilateral disease (Exp. 1) and advanced disease (Exp. 2). Results indicated that while overall cognitive impairment increased with advancing disease, the pattern of neuropsychological impairments were not different with respect to laterality of motor symptoms in either experiment.

Neuropsychological Impairments Associated With Severity of Parkinson's Disease

Intellectual impairment and disease severity tend to parallel one another in patients with Parkinsons disease (PD), but the pattern of development of the neuropsychological impairments contributing to the overall intellectual decline is unknown. This problem was addressed by comparing neuropsychological performance in the early and later stages of PD. Impairment of recent memory, impairment of cognition, and somatic features of depression were seen early and worsened with more advanced disease. Impairment of visuospatial skills, remote memory, language, and mood were observed only in the later stages of PD. These findings suggest that neuropsychological impairments do not develop in a uniform manner with progression of PD.

The picture absurdities test in the evaluation of dementia

Recognition of picture absurdities was found to be significantly impaired in a group of patients with dementia of Alzheimer type compared to patients with dementia syndrome of depression and cerebrovascular dementia, even when matched for age, education, and dementia severity. None of the other neuropsychological measures investigated, including visual recent memory, Ravens progressive matrices, geographic orientation, and copying of geometric figures, resulted in a similar pattern. Although uncertainty remains as to what the picture absurdities test measures, normal performance likely depends on the integrity of many independently assessable variables, in addition to cognition and judgment utilizing visual data.

Electroencephalographic effects of antiepileptic drug therapy

Abstract We investigated the effects of therapeutic levels of antiepileptic drug (AED) monotherapy on computed measures of EEG frequency in seizure patients with normal interictal EEGs. Fourteen patients were taking phenobarbital, 14 were taking phenytoin, 13 were taking carbamazepine, and 12 were taking valproate. One-minute EEG spectra were recorded from Oz-A1 + A2. We measured the predominant alpha band frequency (modal alpha frequency—MAF), fastest alpha band frequency (maximal alpha frequency—MxAF), and highest prominent frequency between 13 and 30 Hz (spectral edge frequency—SEF). Patients taking phenobarbital or valproate had significantly lower MAF than those taking carbamazepine or phenytoin. MxAF did not differ significantly among the four patient groups. SEF was significantly lower in patients on valproate and carbamazepine than in those on other AEDs. Phenobarbital slowed background activity in the interictal EEG, whereas phenytoin and carbamazepine at therapeutic levels did not have such an effect. Valproate produced alpha and beta frequency decrease in the otherwise normal interictal EEG.