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Biomedical subjects

L Findley

Publications and source records attributed to L Findley.

16 recordsLinked to original sources
PubMed1995

Vigilance and automobile accidents in patients with sleep apnea or narcolepsy.

Patients with obstructive sleep apnea or narcolepsy report difficulty remaining alert and attentive. To detect impaired vigilance, we designed Steer Clear, a computer program simulating a long and monotonous highway drive that presents 780 obstacles in 30 min. Sixty-two patients with sleep apnea hit a higher percentage of obstacles (4.3 +/- 0.6% [SEM]) than 12 age- and sex-matched subjects without sleep apnea (1.4 +/- 0.3%; p < 0.05) and 10 age- and sex-matched volunteers (1.2 +/- 0.3%; p < 0.05). Ten patients with untreated narcolepsy hit a higher percentage of obstacles while performing on Steer Clear (7.7 +/- 3.2%) than 10 age- and sex-matched subjects without narcolepsy (1.2 +/- 0.3%; p < 0.05). Poor performance on Steer Clear was associated with a higher auto accident rate in the patients with sleep apnea or narcolepsy (p < 0.01). Twenty-one patients who performed normally on Steer Clear had 1 accident in 5 years (0.05 accident/driver/5 yr), and in none of these accidents were they at fault as drivers. Twenty-five patients who performed poorly on Steer Clear had 5 auto accidents in 5 years (0.20 accident/driver/5 yr), and in 20% of these accidents they were at fault as drivers. Twenty-one patients who performed very poorly on Steer Clear had 8 auto accidents in 5 years (0.38 accident/driver/5 yr), and in 38% of these accidents they were at fault as drivers. These 21 patients who performed very poorly on Steer Clear (hitting > 4.5% of obstacles) had a significantly higher auto accident rate than the patients who performed normally (hitting < 1.8%). We conclude: (1) Patients with sleep apnea or narcolepsy performed more poorly on a test of vigilance, Steer Clear, than did control subjects; (2) Impaired vigilance as measured by Steer Clear is associated with a high automobile accident rate in patients with either sleep apnea or narcolepsy.

Accidents, Traffic↗
PubMed1992

Essential tremor.

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Data Collection↗
PubMed1991

Propranolol in the treatment of acute migraine attacks.

The efficacy of the beta-adrenoceptor antagonist propranolol in the acute treatment of patients in attacks of either classical (migraine with aura) or common migraine (migraine without aura) headache was assessed in a double-blind placebo-controlled crossover trial with fixed doses. The trial was carried out on 25 patients. The treatment period was set at eight weeks, with the provision of shortening or lengthening it if necessary with a maximum period of seventeen weeks. A minimum of three migraine attacks were treated during each treatment period. Patients were assessed according to: the mean duration and mean severity per treatment period of migraine attacks. The secondary efficacy assessment was made on the basis of the percentage of attacks requiring escape medication per treatment period. The study, based on the t-distribution statistical model with a confidence level of 95%, showed that propranolol had no significant effect in aborting acute attacks of migraine when compared with placebo.

Acute Disease↗
PubMed1991

Dopaminergic induced changes in cognitive and motor processing in Parkinson's disease: an electrophysiological investigation.

Event-related potentials and reaction time measures to auditory discrimination tasks of graded difficulty were used to separate cognitive from motor processing time in 27 patients with newly diagnosed, previously untreated Parkinson's disease and later on optimal levodopa treatment. Before treatment event-related potential P3 and task performance were normal but the reaction time was prolonged compared with age matched controls. After treatment P3 latency was significantly prolonged and the reaction time reduced suggesting a dopamine induced dissociation between cognitive and motor processing. In early Parkinson's disease cognitive processing time remains normal but the motor processing time is prolonged. Dopamine replacement is followed by significantly reduced motor processing time despite increased cognitive processing time. Motor processing may reflect the dopamine status of the putamen whereas dopaminergic over-stimulation of other regions may adversely affect cognitive processing in patients treated with levodopa.

Adult↗
PubMed1990

Sensory and cognitive event-related potentials in myalgic encephalomyelitis.

Myalgic Encephalomyelitis (ME) is a form of post viral fatigue syndrome resulting in myalgia and fluctuating fatiguability. Symptoms reflecting central nervous system dysfunction are common and include muscle weakness, headache, sensory disturbances, poor short term memory and impairment of concentration. In view of the fact that sensory and cognitive disturbances are experienced by many patients objective evidence was sought with multi-modality sensory evoked potentials and auditory event-related cognitive potentials in a group of ME patients both with and without the enteroviral antigen, VP1 test positive. The auditory brainstem, median nerve somatosensory and pattern reversal checkerboard visual potentials were normal for all 37 patients tested. In contrast to the sensory potentials significant differences in the mean latencies of the cognitive potential N2 and P3 were found. Reaction times were also significantly prolonged but the performance in terms of error was not significantly affected. No significant difference emerged in any of the parameters for the VP1 test. P3 was abnormal in latency or amplitude in 36% of the VP1 positive patients for the frequency discrimination task and 48% for the more difficult duration discrimination task. The abnormalities indicate attentional deficits in some patients and slower speed of information processing in others. The prolonged latencies observed in these patients have not been observed in patients with depression in many other studies.

Adolescent↗
PubMed1989

Neurology.

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Cerebrovascular Disorders↗
PubMed1989

Post-traumatic tremor.

We present seven cases of tremor caused by mild head injury without loss of consciousness. The interval between head trauma to onset of symptoms was 1 to 4 weeks. A posture and kinetic tremor of the hands and head occurred unassociated with other neurologic signs. Myoclonic-like jerking was frequently present. Neuroimaging studies were normal. Clonazepam administration resulted in tremor reduction in three patients and propranolol decreased tremor in one patient. A tremor, similar to essential tremor, can be a rare complication of head trauma.

Adult↗
PubMed1989

Psychogenic tremors.

We diagnosed 24 patients, 9 men and 15 women ranging in age from 15 to 78 years, with clinically established or documented psychogenic tremors. Clinical presentations were unique, with complex tremors (often resting, postural, and kinetic), unusual temporal profiles (abrupt onset with a variable course), absence of other neurologic signs, inconsistent and incongruous symptomatology, selective disability with ability to perform some functions despite severe tremors, distractibility that lessens or abolishes tremor, atypical tremorgraphic recordings with changing amplitude and frequency, unusual handwriting and drawing specimens, presence of multiple undiagnosed somatizations, unresponsiveness to all treatments, absence of documented disease by laboratory or radiographic tests, presence of psychiatric disease, spontaneous remissions, or recovery with psychotherapy. We present criteria for the diagnosis of psychogenic tremor.

Adolescent↗
PubMed1988

Is there a central nervous withdrawal syndrome associated with discontinuing long-term treatment with propranolol?

Thirty healthy volunteers were treated with beta-adrenoceptor blocking doses of long-acting propranolol for at least 28 days before being randomized to continue propranolol treatment, receive identical placebo under double-blind conditions, or discontinue all treatment. No evidence of a central nervous withdrawal syndrome occurred during the next 28 days as assessed by changes in psychomotor tests, rating scales, visual analogue scales, tremor recordings and melatonin excretion. Three subjects in the placebo withdrawal group but none in the propranolol group complained of insomnia for up to 14 days of the withdrawal period.

Adult↗
PubMed1987

Frequency/amplitude characteristics of postural tremor of the hands in a population of patients with bilateral essential tremor: implications for the classification and mechanism of essential tremor.

Amplitude/frequency characteristics of postural hand tremor in 59 patients with bilateral essential tremor of various degrees of severity were assessed using accelerometric recordings and spectral analysis. Intra-subject comparisons of tremor characteristics between the more and less affected hands were used to control for variability of tremor due to age factors and intersubject differences in amplitude and frequency. Statistical analysis distinguished three different patient groups. Some patients had low amplitude (less than 0.1-0.015 cm) tremor in the less affected limb (which tended to be 7 Hz or more in frequency in the young) and a larger amplitude tremor in the more affected hand which was 1 Hz or more lower in frequency. Other subjects had either bilaterally small or bilaterally large amplitude tremors of similar frequencies. These findings imply that there is a downwards step in frequency between symptomatic tremors of small and large amplitude. The amplitude and frequency of the small amplitude tremors were unrelated but frequency declined with age. The frequency of the large amplitude tremor was generally determined by amplitude but a wide range of amplitudes were compatible with similar frequencies. The frequency of large amplitude tremor also declined with age. It was concluded that there are two types of essential tremor, the smaller amplitude tremor probably derives from an exaggeration of some or all of the mechanisms of normal physiological tremor whereas the larger amplitude tremor probably arises from a separate "pathological" central nervous mechanism. It is not known if or how one may transform into, or be replaced by, the other during progression of the disease.

Adolescent↗
PubMed1979

Chromosome deletion [46,XX,del(20)(q11)] in agnogenic myeloid metaplasia.

A woman in the fourth year of agnogenic myeloid metaplasia was found to have partial deletion of the long arm of chromosome 20 [46,XX,del(20)(q11)] in mitoses of presumably immature myeloid cells from unstimulated cultures of peripheral blood and bone marrow. Cytogenetic studies of peripheral blood lymphocytes showed a normal female karyotype.

Blood Transfusion↗