Biomedical subjects

G Ratcliff

Publications and source records attributed to G Ratcliff.

At least 19 recordsLinked to original sources

PubMed2006

Prediction of long-term occupational performance outcomes for adults after moderate to severe traumatic brain injury.

PURPOSE: To examine predictors of long-term occupational performance outcomes for adults after moderate to severe traumatic brain injury (TBI). METHOD: This study involved analysis of data from a retrospective cohort of adults (N = 306) with moderate to severe TBI discharged from a Pennsylvania rehabilitation treatment facility. Extensive pre-injury sociodemographic, injury-severity, post-injury personal (cognitive, physical, affective), post-injury environmental (social, institutional, physical), and post-injury occupational performance (participation in self-care, productivity, leisure activities) data were gathered from hospital records and using in-person interviews. Interviews occurred at a mean time of 14 (range, 7-24) years post-injury. Hierarchical multiple regression analysis was used to investigate determinants of long-term occupational performance outcomes. RESULTS: Pre-injury behavioural problems, male gender, post-injury cognitive and physical deficits, and lack of access to transportation were significant independent predictors of worse occupational performance outcomes. CONCLUSIONS: The study supports the use of a comprehensive model for long-term outcomes after TBI where pre-injury characteristics and post-injury cognitive and physical characteristics account for the greatest proportion of explained variance.

Adolescent↗

PubMed2004

Preclinical Alzheimer disease: neuropsychological test performance 1.5 to 8 years prior to onset.

OBJECTIVE: To determine if individuals ultimately diagnosed with Alzheimer disease (AD) exhibited evidence of cognitive impairment on neuropsychological tests administered between 1.5 years and 8.1 years before dementia onset. METHODS: A total of 693 community-dwelling individuals, part of the Cardiovascular Health Study, completed a neuropsychological test battery in 1991/92. Subjects were followed annually over the next 8 years (median follow-up = 7.4 years). Seventy-two individuals were ultimately diagnosed with AD (median follow-up = 4.5 years): 24 with AD onset 1.5 to 3.4 years after baseline neuropsychological testing, 20 with AD onset 3.5 to 5.0 years after testing, and 28 with onset 5.1 to 8.1 years after testing. A total of 621 individuals remained nondemented throughout the 8 years of follow-up (median follow-up = 7.5 years). RESULTS: Subjects ultimately diagnosed with AD had poorer scores on baseline neuropsychological measures than subjects who remained nondemented. Although individuals closest to AD onset (i.e., 1.5 to 3.4 years) performed the most poorly, cognitive impairment was detected in individuals who did not develop AD until 5 to 8 years later. CONCLUSIONS: Cognitive changes can be detected well before onset of Alzheimer disease.

Age of Onset↗

PubMed2004

Long-term outcomes after moderate to severe traumatic brain injury.

OBJECTIVE: This research examined the long-term outcomes of rehabilitation patients with moderate to severe traumatic brain injury (TBI). DESIGN: Retrospective cohort study. SETTING AND SUBJECTS: We examined consecutive records of persons with moderate to severe traumatic brain injury who were discharged from a large rehabilitation hospital in Pennsylvania from 1973 to 1989. We interviewed consenting participants (n = 306) up to 24 years post-injury. MAIN OUTCOME MEASURES: Self-rated health, activity limitations, employment, living arrangements, marital status, Community Integration Questionnaire, and use of rehabilitation services. RESULTS: Participants were most limited in activities such as managing money and shopping. Twenty-nine per cent of our participants were working full time. There were significant relationships between activity limitations and residual cognitive impairment at follow-up. Self-rated health was correlated with most instrumental activities of daily living. CONCLUSION: Our findings document health and function in a large post acute TBI population and implications for rehabilitation are discussed.

Activities of Daily Living↗

PubMed2004

Aging with traumatic brain injury: long-term health conditions.

Although traumatic brain injury (TBI) is a leading cause of death and disability in young adults, older adults over the age of 75 are also at high risk for TBI. As even mild injury can lead to disabling consequences, the long-term consequences of TBI need to be better understood, especially as the survival rate has increased dramatically in the last few decades. This research examined the prevalence of long-term health conditions after TBI. Using a retrospective cohort design, we examined consecutive records of adults with moderate to severe TBI discharged from a large rehabilitation hospital in Pennsylvania from 1974 to 1989. Baseline clinical information was abstracted from medical records. We interviewed consenting participants up to 24 years after injury. Our findings show a higher than expected prevalence of self-reported arthritis in the middle-aged population. There was also a high prevalence of problems with sleep and nerves many years post-injury. Some of the health conditions documented in this study could potentially be addressed early in rehabilitation; this study supports the screening of more physical health conditions in persons aging with TBI.

Adult↗

PubMed2001

Patterns of cognitive decline in presymptomatic Alzheimer disease: a prospective community study.

BACKGROUND: Specific patterns of decline over time were evaluated across a spectrum of cognitive measures in presymptomatic Alzheimer disease (AD) within a community sample. METHODS: A total of 551 individuals completed a battery of standard cognitive tests 3.5 and 1.5 years before outcome (clinical onset of AD vs continued nondemented status) within a prospective community-based study of AD. Test score changes in 68 cases (who subsequently developed symptomatic AD) and 483 controls (who remained nondemented) on each of 15 cognitive measures were transformed into z scores adjusted for age, sex, and education. A case-control rate ratio of the proportions of individuals who showed "cognitive decline" on each test was calculated, representing the relative magnitude of cognitive decline on each test in presymptomatic AD compared with normal aging. RESULTS: Declines in Trail-Making Tests A and B and Word List delayed recognition of originals and third immediate learning trial had the highest rate ratios, larger than 3.0 (P<.01). These were followed by Word List delayed recognition of foils and delayed recall, Consortium to Establish a Registry for Alzheimer's Disease Praxis, Clock Drawing, the Boston Naming Test, and Orientation, with rate ratios between 1.7 and 3.0 (P<.05). CONCLUSIONS: Memory and executive dysfunction showed the greatest decline over time in individuals who would clinically manifest AD 1.5 years later. These findings might help us understand the underlying evolution of the early neurodegenerative process. They highlight the importance of executive dysfunction early in the disease process and might facilitate early detection of AD.

Aged↗

PubMed2001

Factors associated with perceived quality of life many years after traumatic brain injury.

OBJECTIVES: To explore factors associated with perceived quality of life (QOL) 8 to 24 years after traumatic brain injury (TBI). DESIGN: Retrospective cohort study. PARTICIPANTS: Two hundred seventy-five individuals who sustained moderate to severe TBI who were discharged from a rehabilitation hospital participated in this study. We interviewed consenting participants up to 24 years after injury. OUTCOME MEASURES: Self-rated Quality of Life Scale. RESULTS: Multivariate linear regression analyses revealed that perceived mental health, self-rated health, gender (women rating QOL higher), participation in work and leisure, and the availability of emotional support were significantly associated with QOL (P <.05). CONCLUSION: The importance of designing ongoing support programs to further reintegrate TBI survivors several years after injury is discussed.

Adolescent↗

PubMed2001

Cognitive correlates of human brain aging: a quantitative magnetic resonance imaging investigation.

The relations between age-related changes in brain structure and neuropsychological test performance in 320 elderly nonclinical volunteers (ages 66-90) were examined by using quantitative MRI data and measures of attention, information processing speed, language, memory, and visuospatial ability. Final path analyses revealed significant brain-behavior relationships for two of the six cognitive measures: the Trail Making Test part B and visual delayed memory. Poorer performance on Trails B was associated with smaller cerebral hemisphere volumes and larger volumes of peripheral CSF, lateral ventricles, and third ventricle. Poorer recall on visual delayed memory was associated with larger volumes of the lateral ventricles and third ventricle. The findings demonstrate a relationship between age-related changes in brain structure and an age-related decline in attention, psychomotor speed, and visual delayed memory. The neurobiological basis for this relationship requires further investigation.

Aged↗

PubMed2001

Speed and capacity of language processing test: normative data from an older American community-dwelling sample.

This study presents normative data for the Speed and Capacity of Language Processing (SCOLP) testfrom an older American sample. The SCOLP comprises 2 subtests: Spot-the-Word, a lexical decision task, providing an estimate of premorbid intelligence, and Speed of Comprehension, providing a measure of information processing speed. Slowed performance may resultfrom normal aging, brain damage (e.g., head injury), or dementing disorders or may represent the intact performance of someone who always performed at the low end of normal. The SCOLP enables the clinician to differentiate between these possibilities. Adequate age-appropriate norms to differentiate dementia from normal aging do not exist. We present data from 424 older community-dwelling Americans (75-94 years old). The results confirm that information processing speed slows with increasing age. By contrast, increasing age has little effect on lexical decision. Thus, our data suggest that the SCOLP shows promise as a tool to help distinguish between normal aging and the early stages of dementia.

Age Factors↗

PubMed2000

Cognitive tests that best discriminate between presymptomatic AD and those who remain nondemented.

OBJECTIVE: To identify the most accurate cognitive measures in discriminating between individuals with presymptomatic AD and individuals who remained nondemented. METHODS: During a 10-year prospective community study, 120 nondemented subjects completed a battery of standard cognitive tests and clinically manifested AD 1.5 years later. Performance on each of 16 cognitive tests was compared between these 120 presymptomatic cases and 483 controls who remained nondemented over the 10-year follow-up period. The area under the receiver operating characteristic (AUC) curve for each test was used to measure its accuracy of discrimination between cases and controls. RESULTS: Among the 16 neuropsychological tests, Word List Delayed Recall discriminated best between cases and controls (AUC = 0.806), followed by the Word List 3rd Learning Trial (0.787), Word List 1st Learning Trial (0.774), and Trail-making Test B (0.773), compared to the Mini-Mental State Examination (MMSE) (0.726). Both Word List Delayed Recall and Word List 3rd Learning Trial were significantly more accurate than the MMSE. The combination of Word List Delayed Recall and Trail-making Test B comprised the optimal set of cognitive measures, with the highest AUC (0.852). CONCLUSION: Measures of delayed recall and executive functions were the best discriminators between those who would manifest AD 1.5 years later and those who would remain nondemented. These findings are relevant for the early detection of AD and, therefore, for prevention and early intervention trials. Executive dysfunction may be a subtle manifestation of incipient AD, along with memory dysfunction.

Aged↗

PubMed2000

Normative data on the Boston Naming Test and two equivalent 30-item short forms.

Because of the significance of the Boston Naming Test (BNT) in the differential diagnosis of the dementias, especially Alzheimer's disease, adequate norms from community-dwelling elderly individuals are essential. The present study describes the development of two new empirically derived equivalent short forms (30 items each) of the test. Normative data for the total BNT and the two equivalent 30-item halves based on item difficulty are presented using the performance of 314 community-dwelling individuals aged 65 and over. Age and education norms are presented using an overlapping midpoint interval strategy.

Aged↗

PubMed2000

Clients' perspectives on problems many years after traumatic brain injury.

This study investigated the types of self-reported main problems that persons report many years following a traumatic brain injury. This preliminary study is part of a large ongoing study of disability and handicap in adults following traumatic brain injury. As part of an extensive interview, subjects were asked an open-ended question regarding their current main problems which they thought resulted from their traumatic brain injury. Responses were obtained from 166 adult subjects (119 men and 47 women) whose time postinjury ranged from 9 to 24 years. Categories for responses were subsequently developed. The most commonly reported categories of problems were those relating to movement (39%), cognition (36%), and sensory impairment (31%). Findings suggest that subjects' long-term concerns were related to specific impairments more than to psychosocial, emotional, or behavioral issues. Methodological issues concerning this research are discussed in relation to findings.

Adaptation, Psychological↗

PubMed1999

Relation of education to brain size in normal aging: implications for the reserve hypothesis.

OBJECTIVE: To examine the relations between education and age-related changes in brain structure in a nonclinical sample of elderly adults. BACKGROUND: Education may protect against cognitive decline in late life--an observation that has led to the "reserve" hypothesis of brain aging. Little is known, however, about the effect of education on age-related changes in brain structure. METHODS: Quantitative MRI of the brain was performed in 320 elderly volunteers (age range, 66 to 90 years) living independently in the community (Mini-Mental State Examination scores > or =24), all of whom were participants in the Cardiovascular Health Study. Blinded measurements of global and regional brain size were made from T1-weighted axial images using computer-assisted edge detection and trace methodology. High measurement reliabilities were obtained. RESULTS: Regression analyses (adjusting for the effects of intracranial size, sex, age, age-by-sex interactions, and potential confounders) revealed significant main effects of education on peripheral (sulcal) CSF volume-a marker of cortical atrophy. Each year of education was associated with an increase in peripheral CSF volume of 1.77 mL (p<0.03). As reported previously, main effects of age (but not education) were observed for all of the remaining brain regions examined, including cerebral hemisphere volume, frontal region area, temporoparietal region area, parieto-occipital region area, lateral (Sylvian) fissure volume, lateral ventricular volume, and third ventricle volume. CONCLUSIONS: The authors' findings demonstrate a relation between education and age-related cortical atrophy in a nonclinical sample of elderly persons, and are consistent with the reserve hypothesis as well as with a small number of brain imaging studies in patients with dementia. The neurobiological basis and functional correlates of this education effect require additional investigation.

Aged↗

PubMed1998

Sex differences in brain aging: a quantitative magnetic resonance imaging study.

BACKGROUND: Little is known about the effect of sex on age-related changes in brain structure. METHODS: Quantitative magnetic resonance imaging of the brain was performed in 330 elderly (age range, 66-96 years) volunteers living independently in the community, all of whom were participants in the Cardiovascular Health Study. Blinded measurements of global and regional brain size were made from T1-weighted axial images by means of computer-assisted edge detection and trace methods. High measurement reliabilities were obtained. RESULTS: Age-specific changes in brain size were significantly greater in men than women for the peripheral (sulcal) cerebrospinal fluid volume, the lateral (sylvian) fissure cerebrospinal fluid volume, and the parieto-occipital region area. Main effects of age were observed for all the remaining brain regions examined (cerebral hemisphere volume, frontal region area, temporoparietal region area, lateral ventricular volume, and third ventricle volume), but these effects were similar in men and women. Asymmetries in brain structures were not affected by aging in either sex. CONCLUSIONS: Our results are generally consistent with the few published studies on sex differences in brain aging and suggest that, for at least some structures, aging effects may be more apparent in men than women. The neurobiological bases and functional correlates of these sex differences require further investigation.

Age Distribution↗

PubMed1998

Effects of literacy and education on measures of word fluency.

As part of a cross-national study of dementia epidemiology, two types of verbal fluency tasks were administered to three groups of subjects, varying in level of literacy and education, recruited from the rural district of Ballabgarh in northern India. Subjects were asked to list items in a given semantic category (animals; fruits) or words beginning with a given sound (the phonemes /p/ and /s/) the latter being a minor modification of the more familiar initial letter fluency task in view of the high prevalence of illiteracy in Ballabgarh. Analysis of variance revealed main effects of education and task with a task by education interaction such that education had a greater effect on initial sound fluency than on category fluency. The results are discussed in terms of their implication for the design of cross-cultural studies and the evidence that the ability to segment speech into phonemic units is dependent on literacy.

Adult↗

PubMed1998

Practical issues in cognitive screening of elderly illiterate populations in developing countries. The Indo-US Cross-National Dementia Epidemiology Study.

The study of the epidemiology of dementia, specifically Alzheimer's disease, in developing countries requires specialized instruments and personnel. Cultural and sub-cultural differences among populations are highly relevant to the design of such instruments. Over and above the cultural issues, it is widely recognized that low education and illiteracy pose considerable challenges to reliable and valid cognitive screening. The overall objectives of the Indo-US Cross-National Dementia Epidemiology Study were: a) to determine the prevalence and incidence of, and risk factors for, Alzheimer's and other dementias in a defined Indian community; and b) to compare these results with those found in a defined American community. To achieve these epidemiological objectives, our first task was to develop, systematically and empirically, suitable cognitive and activities assessment screening instruments for use in India, which would 1) be culturally fair, psychometrically sound, and valid for a population with little or no education; 2) be optimally sensitive and specific for dementia; and 3) allow not only the identification but also the more detailed characterization of dementia, and of normal and abnormal cognitive aging. In this paper we address the practical issues involved in the development and administration of the modified cognitive screening battery in our rural Indian context.

Aging↗

PubMed1998

Poststroke depression and anxiety: different assessment methods result in variations in incidence and severity estimates.

Patients with right and left hemisphere stroke (RH, LH) and a control group (CG) were administered a structured clinical interview (SCID-R) and rating scales for anxiety and depression (Center for Epidemiologic Studies Depression Scale, Beck Anxiety Inventory, and Hamilton Depression Rating Scale). The three groups did not differ when compared for the mean level of distress on the rating scales or frequency of mood or anxiety disorder diagnosis using the SCID-R. By contrast, participants in the LH group were more likely to be classified as distressed using rating scales cutoff scores and on measures of severity when compared only to the RH group. The rating scales were sensitive to psychiatric disorders, but lacked specificity in all groups. There were significant correlations between scales suggesting the rating scales measure a common factor in the controls, while in the stroke groups associations were weaker and less likely to be significant. Together, these results suggest the need for caution in using rating scales of depression and anxiety in neurologic patients and support the notion that these scales are sensitive to distress rather than specific for identifying depressive and anxiety disorders.

Aged↗

PubMed1998

Neurologic factors associated with cognitive impairment in a rural elderly population in India: the Indo-US Cross-National Dementia Epidemiology Study.

Few reports exist of cognitive impairment and associated factors in developing countries. An age-stratified random sample of 388 men and women, 55 years and older, was drawn from a community-based population in the rural area of Ballabgarh in northern India. We classified as "cognitively impaired" those subjects who had scores below the 10th percentile of the population on a general mental status test (the Hindi Mental State Exam, HMSE) and, separately, on a memory test (Delayed Recall of a 10-Item Word List, DRWL). Three hundred seventy-six subjects also underwent a standardized neurologic history and examination. Neurologic factors associated with cognitive impairment, after adjusting for age, gender, and literacy, were history of impaired consciousness and findings of gait disturbance, diminished deep tendon reflexes, and the presence of at least one primitive reflex. We speculate that there may be unique risk factors in developing countries such as nutritional deficiencies leading to focal deficits and cognitive impairment.

Aged↗

PubMed1996

Cognitive test performance in a community-based nondemented elderly sample in rural India: the Indo-U.S. Cross-National Dementia Epidemiology Study.

Interpretation of cognitive test performance among individuals from a given population requires an understanding of cognitive norms in that population. Little is known about normative test performance among elderly illiterate non-English-speaking individuals. An age-stratified random sample of men and women, aged 55 years and older, was drawn from a community-based population in the rural area of Ballabgarh in northern India. These Hindi-speaking individuals had little or no education and were largely illiterate. A battery of neuropsychological tests, specially adapted from the CERAD neuropsychological battery, which was administered to this sample, is described. Subjects also underwent a protocol diagnostic examination for dementia. Norms for test performance of 374 nondemented subjects on these tests are reported across the sample and also by age, gender, and literacy.

Aged↗