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F W Bylsma

Publications and source records attributed to F W Bylsma.

At least 37 records · Page 2Linked to original sources
PubMed1994

EEG power spectra in Huntington's disease: clinical and neuropsychological correlates.

Quantitative power spectral analysis (PSA) was applied to frontal (F3, F4, F7, F8), temporal (T5, T6), and occipital (O1, O2) EEGs of 16 Huntington's disease (HD) patients and eight healthy control subjects. PSA revealed HD patients' EEGs to be abnormal: (i) raw and percent Alpha power were reduced; (ii) raw and percent Theta power were reduced at F3 and F4; (iii) percent Delta and percent Beta power were increased; (iii) Theta frequency was reduced by approximately 1.0 Hz. Frontal and temporal EEG power measures and decreased EEG amplitude correlated with severity of neurological and cognitive impairment.

Adult↗
PubMed1994

Assessing patient dependence in Alzheimer's disease.

BACKGROUND: While cognitive and functional deficits are the hallmark of Alzheimer's disease (AD), loss of social function (and the dependence this implies) is also critical, especially in early stages of disease. Little attention has been directed to this facet of dementing disease. We describe a scale for assessing dependency in AD and present a baseline profile of dependency in a cohort of AD patients. METHODS: In a study of the predictors of the course of AD, 233 patients in early stages of disease (modified MMS > or = 30) were assessed. Psychometric properties of the dependence scale were established. To validate the scale, dependence scores at baseline were correlated with a series of measures assessing cognition and function. The course of dependency over 18 months of follow-up was also analyzed. RESULTS: The scale shows adequate reliability (test-retest, intraclass correlation). Dependence stage was related to other measures of disease severity. Scalogram analysis shows that the dependence scale is consistent with the course of functional loss established for dementing disease. Prospective data indicate sensitivity of the scale to disease progression. CONCLUSION: Dependency is a distinct, measurable component of dementing disease and should be considered an important outcome in studies of AD.

Activities of Daily Living↗
PubMed1994

The effects of Alzheimer disease on driving-related abilities.

Ten Alzheimer disease (AD) patients and 12 healthy elderly controls were evaluated on two tests of driving-related abilities: the Driver Performance Test (DPT) and the Driving Advisement System (DAS). Subjects were administered a battery of neuropsychological tests to determine if severity of dementia in AD correlates with driving performance. On the DPT, the AD patients scored in the average range in two of five skill areas (predicting the effects of a hazard, deciding how to avoid it); below average in two areas (searching for a hazard, executing evasive actions); and poorly in one area (identifying hazards). The elderly controls scored at an average level in all five skill areas. On the DAS, AD patients were significantly slower than the elderly controls on simple, two-choice, and conditional reaction time tests and were much slower than drivers in general. The AD patients' performances on two cognitive tests, the Mini-Mental State Examination (MMSE) and the Category Fluency Test, correlated significantly with aspects of performance on the DPT and the DAS. Although these are preliminary results from a pilot investigation, they suggest that AD patients' driving-related abilities are adversely affected by the disease and that driving-related performance tests and neuropsychological tests may be useful in assessing the impact of AD on driving.

Aged↗
PubMed1993

Assessment of adaptive functioning in Huntington's disease.

The Huntington's Disease Activities of Daily Living (HD-ADL) scale is a 17-item informant-completed instrument for rating adaptive functioning in Huntington's disease (HD) patients. To assess the reliability and clinical correlates of the HD-ADL, it was administered along with the Mini-Mental State Exam (MMSE) and Quantified Neurological Exam (QNE) to 93 HD patients. The HD-ADL has high internal consistency (coefficient alpha = 0.91). Principal components factor analysis of the HD-ADL revealed four factors (General Functioning, Domestic Activities, Home Upkeep, and Family Relationships) accounting for 72% of the total variance. MMSE score, motor impairment score, and duration of disease were the best predictors of HD-ADL score. Similar results were obtained in an independent replication sample of patients. The HD-ADL scores correlate with Shoulson and Fahn's total functional capacity (TFC) index (r = -0.89). The HD-ADL scale is a reliable and valid instrument for assessing adaptive function in HD patients.

Activities of Daily Living↗
PubMed1993

Cognitive and motor correlates of everyday functioning in early Huntington's disease.

The present study documents the prevalence of deficits in the ability to carry out a variety of activities of daily living in early Huntington's disease (HD), along with the associated neuropsychological and motor deficits. Eighty patients with HD were assessed with the Huntington's Disease-Activities of Daily Living Questionnaire (HD-ADL). Sixty-seven patients also completed a comprehensive assessment of cognitive and voluntary motor functioning and chorea. The latter measures were correlated with HD-ADL total score and with most HD-ADL items, but not with those items dealing with marital and family relationship adjustment. Findings suggest that psychomotor speed and the ability to regulate attention may be particularly important determinants of everyday functioning in mild HD. Consistent with previously reported observations, this appears to be true even after accounting for individual differences in the severity of chorea and voluntary motor impairment.

Activities of Daily Living↗
PubMed1992

Personal and extrapersonal orientation in Huntington's disease patients and those at risk.

Two aspects of spatial cognition, personal and extrapersonal orientation, were studied in 21 patients with Huntington's disease, 49 individuals at risk for the disease, and 41 healthy control subjects. Personal orientation was assessed using the Standardized Road Map Test of Directional Sense. Extrapersonal orientation was measured using a route-walking task under two conditions--with and without turning the body while traversing the routes. Relative to normal controls, HD patients performed more slowly on the personal orientation test, and less accurately on the extrapersonal orientation task in the TURN, but not the NO-TURN condition. At-risk individuals performed like the normal control subjects on all measures. The results suggest a deficit in personal but not extrapersonal orientation in HD. It is suggested that disruption of fronto-striatal pathways mediates this deficit.

Adult↗
PubMed1992

Oculomotor performance in obsessive-compulsive disorder.

OBJECTIVE: Neuroimaging studies have shown abnormalities of the frontal cortex and basal ganglia in persons with obsessive-compulsive disorder. Since lesions in the frontal cortex and basal ganglia areas affect performance on goal-guided saccadic eye movements, this study investigated the relation between the diagnosis of obsessive-compulsive disorder and oculomotor performance. METHOD: Eleven patients with the clinical diagnosis of obsessive-compulsive disorder and 14 normal subjects were assessed with respect to their performance on both visual-guided and goal-guided oculomotor tasks. Fixation performance was also measured. RESULTS: The group with obsessive-compulsive disorder had a very significantly greater error rate and a significantly greater rate of inaccurate saccades on the goal-guided antisaccade task, whereas they were not different from the normal group in reaction time, saccadic velocity, and accuracy on the visual-guided saccade task. The distribution of error rates for the patients with obsessive-compulsive disorder was broad, with more than one-half outside the range of the normal group. Most of the abnormal findings were among male patients. CONCLUSIONS: The results support the hypothesis of a relationship between impaired performance on goal-guided saccadic eye movement tasks and the diagnosis of obsessive-compulsive disorder, but they also suggest a gender-related subgroup within the group with obsessive-compulsive disorder.

Basal Ganglia↗
PubMed1991

Long-term retention of implicit learning in Huntington's disease.

Implicit learning was examined in 15 Huntington's disease (HD) patients and 15 control subjects (NC) using a semantic decision-making task. HD patients demonstrated only slightly reduced priming; like NC subjects, their decision times decreased over repeated presentations, though to a somewhat lesser degree. On explicit recognition testing, the HD group made significantly more false positive errors than did the control group, suggesting an impairment of effortful retrieval. The groups displayed equivalent retention of implicitly learned material after 6 months. The striatal neuronal loss of early Huntington's disease does not markedly affect priming or retention of primed stimuli, but may alter explicit memory judgements.

Adult↗
PubMed1991

Benzodiazepine-induced and anticholinergic-induced delirium in the elderly.

Encompassing the range from subtle cognitive impairments to frank delirium, toxicity due to benzodiazepines and to anticholinergic-containing compounds is reviewed. For benzodiazepines, an extensive literature suggests that they impair immediate and delayed memory, psychomotor performance, and subjective complaints of station. This, in several studies, results in increased patient morbidity (e.g., increasing risk of hip fractures). Anticholinergic compounds are widely utilized in managing elderly patients, particularly nursing home residents. Toxicity from anticholinergic compounds, detected by anticholinergic drug levels, is significantly correlated with the presence and severity of delirium in a number of settings including postoperative patients and elderly nursing home residents. Possible means of identifying the syndrome by prediction of dose and type of medication, as well as by quantitative EEG, are reviewed.

Aged↗
PubMed1991

Psychosis and physical aggression in probable Alzheimer's disease.

OBJECTIVE: The purpose of this study was to determine the frequency and type of psychotic symptoms in patients with probable Alzheimer's disease and to test whether there is a relationship between specific psychotic symptoms and episodes of physical aggression. METHOD: From 209 patients with possible or probable Alzheimer's disease who had been assessed in a research clinic every 6 months for up to 4.5 years, 181 subjects with probable Alzheimer's disease were selected for study. On the basis of the summary note for each visit in the patients' charts, the presence of delusions, hallucinations, misidentifications, and episodes of physical aggression was determined. Data regarding psychotic symptoms and aggression were available for 170 and 169 subjects, respectively. RESULTS: Delusions had been reported for 74 (43.5%) of the patients and were the most frequent psychotic symptom; persecutory delusions were the most common type. Physical aggression had been noted for 50 (29.6%) of the patients. Delusions and misidentifications frequently preceded and were significantly associated with episodes of physical aggression. The presence of delusions was a significant predictor of physical aggression but accounted for only 3.5% of the variance. CONCLUSIONS: This study suggests that delusions are a risk factor for physical aggression in patients with probable Alzheimer's disease who have moderate to severe cognitive impairment. As delusions accounted for only a small percentage of the variance, further research is needed to identify other variables that may be significant predictors of physical aggression in this population.

Aged↗
PubMed1990

Aspects of procedural memory are differentially impaired in Huntington's disease.

Procedural memory encompasses several phenomena, including motor and perceptual learning, cognitive rule learning and priming. These subclasses are differentially affected by differing neuropathologies, suggesting their functional independence and reliance upon different neural substrates. To test this hypothesis, performance on a maze learning task was compared in 15 Huntington's disease (HD) patients and 15 normal controls (NC) to assess specific route learning, cognitive skill learning and the effects of route predictability on performance. Results revealed that the HD group: (1) showed normal learning curves for a specific maze route; (2) are deficient in generalizing the cognitive skills across mazes; and, (3) fail to improve performance on a maze with a predictable route relative to mazes with unpredictable routes. These results are interpreted as supporting the independence of procedural memory subclasses. The basal ganglia are suggested as important structures in mediating the ability to generalize skills and appreciate patterned organization in to-be-acted-upon stimuli.

Journal Article↗
PubMed1989

The effects of background illumination and stimulant medication on smooth pursuit eye movements of hyperactive children.

Problems with visual information processing have been reported in children with the diagnosis of attention deficit disorder with hyperactivity (ADD H), and deficits in oculomotor control have been posited as an important factor in this phenomenon. To assess aspects of oculomotor performance, smooth pursuit eye movements (PEMs) were recorded electrooculographically in 20 ADD H and 20 age-matched control children and computer-analyzed for discrete (velocity arrests) and global (root mean square error) disruptions. The effects of stimulant medication (methylphenidate), together with manipulations designed to influence behavioral (attention) and physiological (cerebellar) processes involved in PEM performance, were examined. The tracking patterns of nonmedicated ADD H children contained significantly more discrete aberrations on baseline conditions. Although no single experimental manipulation significantly improved tracking performance in ADD H children, combining all experimental conditions did normalize PEMs in these subjects. Slight improvements in PEM performance in association with medication correlated positively with dose of medication and with medication-related improvements in behavior. In light of these data, arguments are presented in support of (a) hypoarousal as a contributing factor underlying oculomotor difficulties in ADD H children, and (b) subcortical involvement in PEM dysfunction.

Attention↗
PubMed1988

Dark condition normalization of smooth pursuit tracking: evidence of cerebellar dysfunction in psychosis.

Smooth pursuit tracking performance was evaluated in psychotic (n = 20) and normal control subjects (n = 20) during light and dark testing conditions using computer-based analyses of electrographically recorded tracking patterns. Previously reported impaired tracking in psychotics tested under light conditions was reaffirmed. However, the tracking patterns of patients during the dark condition not only resembled those of controls under similar conditions, but were no longer significantly different from controls' light condition performance. Among several possible bases for these results which are considered, the involvement of cerebellar dysfunction in these patients is emphasized.

Adult↗
PubMed1987

Variations in nuchal muscle tonus following paradoxical sleep deprivation in the rabbit.

Although tonic inhibition of nuchal or facial musculature is considered an intrinsic component of paradoxical sleep (PS) in mammals, this inhibition is either absent or greatly attenuated in the rabbit. To further explore the characteristics of this phenomenon in this species, variations in quantified nuchal muscle activity were examined before, during and following 24 h of PS deprivation. It was postulated that if the substrate for PS-associated tonic electromyogram (EMG) inhibition is present, this procedure--which is known to affect both tonic and phasic components of PS--might enhance such inhibition. For these investigations chronically implanted rabbits (electroencephalographic, eye movement and nuchal muscle placements) were recorded continuously for 5 consecutive days (two day baseline, one day deprivation, two day recovery). Muscle activity was quantified by resetting integration techniques and comparisons made of activity levels before, during and after PS episodes across conditions. The deprivation procedure significantly reduced the amount of PS relative to baseline values, and a significant PS increase (rebound) occurred during postdeprivation recordings. Across-condition EMG-related effects included the corroboration of previous reports of an absence of nuchal atonia during PS, a significant diurnal variation in EMG activity--with greater activity occurring during the dark portion of the light-dark cycle, and enhanced activity immediately following PS episodes relative to either pre-PS or PS levels. Deprivation-related changes in quantified EMG activity included a pre-PS decrease during both the last 12 h of deprivation and the initial 12 h of recovery sleep, and an enhancement of EMG activity during PS.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

The effects of dark adaptation on pursuit tracking dysfunction in psychotics with impaired vestibular suppression.

Smooth pursuit eye tracking performance, evaluated by electronic processing and subjective ratings, was assessed in actively psychotic psychiatric patients and normal controls under conditions of light and dark adaptation and was related to subjects' ability to suppress vestibular nystagmus induced by caloric irrigation. Patients' tracking performance was significantly inferior during the light-adapted condition on all tracking measures. Dark-adaptation eliminated group differences based on electronic analyses, but subjective ratings--which showed a variable relationship to the other tracking measures--did not reflect this improvement. Vestibular nystagmus suppression was significantly impaired in patients relative to controls and this impairment, coupled with smooth pursuit dysfunction and marked improvement in tracking performance during dark-adaptation, suggests that cerebellar dysfunction contributes significantly to tracking dysfunction in psychotic patients.

Adult↗
PubMed1986

Effects of paradoxical sleep deprivation in the rabbit.

The effects of nonpharmacologically-induced deprivation of paradoxical sleep for a 24 hour period were studied in rabbits. Response characteristics commonly associated with the deprivation procedure in other species were observed, as well as features apparently peculiar to the rabbit. Like other mammals, rabbits: (1) show increased attempts to experience PS during the deprivation procedure relative to the baseline occurrence of PS; (2) become increasingly difficult to arouse from PS as the deprivation period progresses; (3) show increased amounts of PS (rebound) in post-deprivation recordings relative to baseline; and (4) compensate for only one-third of the PS deficit incurred during deprivation. Rabbits' response to PS deprivation differs from other mammals in the following ways: (1) the deprivation procedure is truly selective, significantly affecting only amounts of PS and not total sleep time or other sleep stages; (2) the rebound response is restricted to the light phase of the light-dark cycle on the first recovery day; and (3) as indexed by eye movement density, phasic activity during PS is not enhanced during the recovery period. Given that the crucial factor in the PS deprivation-compensation phenomenon is thought to be the deprivation and subsequent enhanced occurrence of phasic events, and considering that events within the oculomotor system have been emphasized in this regard, the results of this investigation suggest the existence of species differences regarding the nature and form of the compensatory response to PS deprivation.

Animals↗