Dissociations between skill learning and verbal recognition in amnesia and dementia.

Patients with Huntington's disease (HD), patients with alcoholic Korsakoff's syndrome, and normal control subjects were compared on tests of skill learning (mirror reading) and verbal recognition. Like previously reported results, the patients with Korsakoff's syndrome acquired the mirror-reading skill at a normal rate but were severely impaired in their recognition of the words used on the mirror-reading task. In contrast to the amnesic patients, the demented patients with HD were retarded in their ability to acquire this skill but showed normal verbal recognition. Besides emphasizing substantial differences in the anterograde substantial differences in the anterograde memory disorders of these two patient populations, the results suggest that the memory disorder of patients with HD may appear much more severe when recall rather than recognition test paradigms are employed. This failure of recall by the patients with HD may be due to an inability to generate strategies necessary to search their short- and long-term memories.

Factors associated with slow progression in Huntington's disease.

The rate of disease progression was assessed for 42 persons affected by Huntington's disease who had been neurologically examined at least six times and followed up for at least 3 years. Disease progression was assessed by a disability rating scale administered at each examination. Slow progression was associated with older age at onset of disease and with heavier weight (body mass index) at the first examination. Men tended to have a slower disease progression than did women, and this was particularly evident among men inheriting Huntington's disease from affected mothers. Neither the butyrophenone haloperidol nor the tricyclic antidepressant imipramine were related to rate of progression. Assessments of depression, hostility, and tobacco use were also unrelated to rate of progression. Clinical trials in Huntington's disease should consider these factors when designing therapeutic studies.

Phenotypic variation in 2 Huntington's disease families with linkage to chromosome 4.

Variability of expression of the Huntington's disease (HD) gene is illustrated in 2 families with linkage of DNA restriction fragment length polymorphism to the short arm of chromosome 4. In 1 family, affected persons from 3 generations show 50-year variation of onset age. The member with the latest onset age (67) died at 91 with autopsy-confirmed HD. The next generation had hypotonic chorea beginning in the 4th decade with death in the 5th. In the 3rd generation, a rigid patient, inheriting the illness from an affected father, had a much earlier onset at 16, while her siblings had chorea beginning in the 3rd decade. In the 2nd family, several members had cerebellar signs, chorea, and dementia. MRI and CT revealed olivoponto-cerebellar and striatal atrophy. These phenotypes may be the result of different allelic genes at the HD locus or unlinked autosomal modifying loci influencing the expression of the HD gene.

Peripheral neuropathy in arsenic smelter workers.

We conducted a double-blind controlled study of individuals exposed to arsenic trioxide in a copper-smelting factory. Subjects fell into three categories of peripheral neuropathy: none, subclinical, and clinical. The subclinical group had no symptoms or signs of numbness or reduced reflexes, but did have reduced nerve conduction velocity and amplitude measurements. Clinical neuropathy groups had signs and symptoms of neuropathy and electrophysiologic abnormalities. The clinical and subclinical groups correlated with increased content of arsenic in urine, hair and nails. The incidence of subclinical and clinical neuropathy was greater in arsenic workers than in unexposed controls.

Motor planning in Parkinson patients.

This study was designed to determine if Parkinsonian patients exhibited a deficit in motor planning. Thirty adult males, 15 with Parkinson's disease and 15 normal controls, were given a gestural test which had two components. The first component required the symbolic representation of implement usage on verbal command and on imitation (representational items) and the second component required the imitation of non-symbolic hand positions (non-representational items). The results indicated that Parkinsonian patients performed at a significantly lower gestural level on the representational tasks and made significantly more spatial errors on non-representational tasks than the normal controls.

The effect of verbal mediators on the pictorial memory of brain-damaged patients.

Patients with alcoholic Korskoff's syndrome, Huntington's Disease, Alzheimer's Disease or right-hemisphere damage were administered a picture recognition task in which they attempted to associate specific human and animal figures with particular scenic backgrounds. Under one condition (no-story), no explicit verbal cues were provided to help the patients associate the figures with the scenes; in a second condition, stories, stories linking the figures to the background scenes were read to the patients during the study period. Although all four patient groups were impaired in picture-context recognition under the no-story condition, the groups differed significantly in their ability to use the stories to improve their pictorial memory. The Huntington and right-hemisphere patients' picture recognition showed significant improvement when stories were provided, whereas the Korsakoff and Alzheimer patients failed to use this verbal material in a productive manner. The groups also differed in their tendency to make intrusion (i.e., perseverative) errors on the picture-context recognition task. These group differences may be related to the combination of language, cognitive and motivational deficits associated with each disease.

Arterial blood gases and pH during sleep in chronic obstructive pulmonary disease.

Arterial blood gases were measured during 7 hours of sleep in 15 patients with severe stable chronic obstructive pulmonary discrease (COPD); 6 awake patients with COPD studies in recumbency for an average of 5 hours served as controls. Mean maximal decrease in arterial oxygen partial pressure (PaO2) (plus or minus SD) was 13.5 plus or minus 3.9 mm Hg for sleeping patients (p less than 0.005) and 5.5 plus or minus 1.7 mm Hg for controls (p less than 0.1), respectively. Changes in pH during sleep were of the magnitude expected with acute changes in arterial carbon dioxide partial pressure (PaCO2) in patients with chronic hypercapnia. Consistent changes in heart rate, respiratory frequency or cardiac rhythm were not observed during sleep. Nocturnal worsening of hypoxemia could be explained by alveolar hypoventilation in six sleeping patients and in five controls; in nine sleeping patients, further impariment of ventilation-perfusion mismatch also contributed to worsening of hypoxemia. There was no relationship between the decrease in PaO2 during sleep and the degree of airways obstruction or the PaO2 level when awake. Because of low PaO2, when awake, a fall in PaO2 during sleep brings values into the steep part of the oxyhemoglobin dissociation curve where slight changes in PaO2 result in marked changes in oxygen content. All patients with COPD whose waking PaO2 was below 60 mm Hg had PaO2 below 50 mm Hg during sleep; nocturnal oxygen therapy should be considered in such patients, particularly in the presence of polycythemia or troublesome right-sided heart failure.

Lack of hepatotoxicity with naltrexone treatment.

Naltrexone, a specific opiate receptor antagonist, is used clinically in the treatment of heroin addiction and more recently, for the treatment of dyskinesia associated with Huntington's disease (HD). Naltrexone may act as a potential hepatotoxin, as reflected in the elevation of transaminase levels. However, one study concluded that, for a brief treatment period of 12 weeks, there is no contraindication to naltrexone treatment based solely on increased hepatic enzyme values. This study monitored liver transaminase levels, in ten HD patients receiving daily doses, between 50 mg/day and 300 mg/day, of naltrexone for periods of 10 to 36 months. Serum glutamic oxalacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT) levels were obtained before treatment and at intervals of 1 to 4 months during treatment. Only one of the ten patients treated with naltrexone had increased levels of both SGOT and SGPT, whereas one other patient showed elevated levels of SGPT. These elevations, which initially appeared dose related decreased to normal limits with continued treatment. Because many of the patients were receiving other medications, a combination of drugs with naltrexone may contribute to the increased transaminase levels seen in two of the patients. In summary, chronic administration of naltrexone in doses up to 300 mg/day for periods up to 36 months does not significantly change hepatic function, as measured by SGOT and SGPT levels.

Retrograde amnesia in Parkinson's disease.

Retrograde amnesia was assessed in demented and non-demented Parkinson's patients using a test of remote memory spanning the years from 1920-1979. Results indicated that the demented patients 1) scored significantly below normal controls and 2) had equal impairment for all time periods. This pattern was like that seen in other dementing illnesses (i.e., Huntington's and Alzheimer's diseases), but different from that in amnesic disorders, such as Korsakoff's syndrome. The data, therefore, suggest qualitative differences in pattern of remote memory loss between the dementias and amnesic syndromes.

Cyclic alterations of blink reflexes: an EEG and EMG study during wakefulness and sleep.

Studies of the blink reflex were undertaken in twelve normal subjects during wakefulness and different sleep stages. The early R1 and the late R2 components of the reflex were analyzed. R1 was present in only one subject during stage I sleep and subsequently disappeared in stage II to IV. In all subjects, R2 was gradually diminished and totally disappeared during stage IV. During the REM stage, R1 was seen in only four-out-of-twelve subjects but all R2 returned. Alterations of R1 and R2 of the blink reflex during different sleep stages suggest that the underlying mechanism includes both supranuclear and infranuclear activities. Our finding strengthens further the notion of dual hyponogenic mechanisms for sleep.

Omental transposition for cerebral infarction: a 13-year follow-up study.

BACKGROUND: During the past decade there has been increasing use of omental transposition to the brain of patients who experienced neurologic sequelae after a cerebral infarction. This paper reports the long-term neurologic effects seen in a patient who underwent omental transposition 31 months after a stroke. Her postoperative follow-up period has been 13 years. CASE DESCRIPTION: The patient had an expressive aphasia, a right hemiparesis and the inability to read which occurred immediately after her stroke. After surgery she demonstrated subjective and objective improvement in her speech and mobility. She also regained her ability to read shortly after surgery. CONCLUSION: The patient demonstrated that omental transposition to the brain can improve neurologic function in the presence of a long-standing cerebral infarction and that the clinical improvement can be maintained over an extended period.

Neurologic evaluation of a population exposed to arsenic in Alaskan well water.

One hundred forty-seven persons exposed to arsenic from well water were evaluated by neurologic examination and nerve conduction studies. Total arsenic concentrations in well water ranged from 1 to 4781 micrograms/L and from 6 to 4964 micrograms/L in urine; a calculated index of arsenic ingestion ranged from 1 to 4521 micrograms/day. No dose-response relationship existed between arsenic ingestion and symptoms or physical findings compatible with peripheral neuropathy. Five of six persons with symptoms or physical findings suggestive of sensory neuropathy had normal nerve conduction velocities. Thirteen persons with elevated arsenic ingestion but no signs or symptoms of neuropathy had one or more abnormal nerve conduction velocities. No dose-response relationship, however, existed between arsenic ingestion and nerve conduction velocities. The authors concluded that arsenic ingestion from well water at the concentrations found in this Alaskan community did not result in clinical or subclinical neuropathy.