Current concepts in the management of femoroacetabular impingement.
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Acetabulum↗
Biomedical subjects
J R Crawford
Publications and source records attributed to J R Crawford.
Personal disturbance scale: factor structure confirmed in a large nonclinical sample.
The two-component structure of anxiety and depression items of the short form Personal Disturbance Scale, reported in an earlier clinical study of 480 adult psychiatric patients, was substantially replicated in a large nonclinical sample of 758 adults.
Adolescent↗
Differential deficits in expression recognition in gene-carriers and patients with Huntington's disease.
Previous studies in symptomatic patients and asymptomatic gene-carriers of Huntington's disease (HD) reported a differential deficit in the recognition of facial expressions of disgust. This impairment may point to involvement of the basal ganglia in the recognition of disgust. In this study, we compared the performance of 20 patients with symptoms of HD, 20 gene-carriers of HD and 20 healthy controls on two tests of facial expressions in order to further investigate the role of the basal ganglia in disgust recognition. Recognition of fear, rather than disgust, was most severely impaired in the patients, who were also impaired at recognising expressions of anger, disgust and sadness. Direct testing for a differential deficit in disgust at the group level (and at the level of individual HD cases) revealed that the patients were in fact significantly more impaired on the other negative expressions than on disgust. The gene-carriers were not impaired on any expression, although there was a trend for the gene-carriers to be poorer at recognising fearful faces than the controls. We argue that the expression recognition performance of the patients and gene-carriers simply reflects differences in task difficulty, rather than dysfunction of any mechanisms dedicated to specific emotions. In contrast to previous studies in patients or gene-carriers of HD, our findings provide no evidence for a role of the basal ganglia in the recognition of disgust and cast doubt on whether results from HD patients and gene-carriers can be used in support of a double dissociation between recognition of disgust and fear.
Adult↗
Compression of the sciatic nerve by wear debris following total hip replacement: a report of three cases.
Pain in the distribution of the sciatic nerve is common in the elderly. In the presence of a long-standing joint replacement, consideration should be given as to whether compression might be due to an extraspinal cause. We present three women, in whom a mass of wear debris from a previous total hip replacement caused compression of the sciatic nerve posterior to the hip. The symptoms were relieved immediately following operation.
Aged↗
Performance on tests of frontal lobe function reflect general intellectual ability.
Recent studies have indicated that performance on tests of frontal lobe function are highly associated with general intellectual ability (g). Some authors have even claimed that the available evidence does not support a more specific account of frontal lobe function than to provide a general intellectual function for the performance of goal directed tasks. We examined the relationship between performance on the WAIS-R (as a measure of g) and performance on standard tests of frontal lobe function in 123 healthy individuals. Our results demonstrate that in healthy individuals (i) performance on the most popular tests of frontal lobe function shares significant variance, and (ii) a large proportion of that shared variance is highly associated with performance on the Wechsler Adult Intelligence Scales-Revised (WAIS-R), so that the tests are similar to the extent that they measure g. Performance on the Modified Card Sorting Test (MCST), however, is not related to g. The results support the claim that many tests of frontal lobe function measure primarily a non-specific intellectual function but also indicate that some tests, like the MCST, may be assessing more specific cognitive operations.
Adolescent↗
Investigation of the single case in neuropsychology: confidence limits on the abnormality of test scores and test score differences.
Neuropsychologists often need to estimate the abnormality of an individual patient's test score, or test score discrepancies, when the normative or control sample against which the patient is compared is modest in size. Crawford and Howell [The Clinical Neuropsychologist 12 (1998) 482] and Crawford et al. [Journal of Clinical and Experimental Neuropsychology 20 (1998) 898] presented methods for obtaining point estimates of the abnormality of test scores and test score discrepancies in this situation. In the present study, we extend this work by developing methods of setting confidence limits on the estimates of abnormality. Although these limits can be used with data from normative or control samples of any size, they will be most useful when the sample sizes are modest. We also develop a method for obtaining point estimates and confidence limits on the abnormality of a discrepancy between a patient's mean score on k-tests and a test entering into that mean. Computer programs that implement the formulae for the confidence limits (and point estimates) are described and made available.
Brain Damage, Chronic↗
The homophone meaning generation test: psychometric properties and a method for estimating premorbid performance.
The Homophone Meaning Generation Test (HMGT; Warrington, 2000) is a new measure of verbal fluency that has been demonstrated to be sensitive to the presence of anterior lesions. In the present study we used the HMGT healthy standardization sample (N = 170) and demonstrate that scores on the HMGT do not differ significantly from a normal distribution and that the test has adequate reliability (alpha = .82). A table for obtaining confidence limits on an individual's score is presented. A regression equation for the estimation of premorbid HMGT performance was constructed using the National Adult Reading Test as the predictor variable. In a sample of 36 cases with anterior lesions estimated premorbid scores were significantly higher than obtained scores (p < .001). Premorbid ability acted to suppress group differences on the HMGT; the partial correlation between neurological status (healthy vs. anterior lesion) and HMGT performance controlling for premorbid ability (.53) was significantly higher than the raw correlation (.44). In addition, hierarchical discriminant function analysis demonstrated that the inclusion of premorbid ability improved classification over that achieved by HMGT scores alone. These results support both the underlying rationale and the clinical utility of controlling for premorbid performance when interpreting verbal fluency scores.
Adult↗
The NART as an index of prior intellectual functioning: a retrospective validity study covering a 66-year interval.
BACKGROUND: The National Adult Reading Test (NART) is widely used in research and clinical practice as an estimate of pre-morbid or prior ability. However, most of the evidence on the NART's validity as a measure of prior intellectual ability is based on concurrent administration of the NART and an IQ measure. METHOD: We followed up 179 individuals who had taken an IQ test (the Moray House Test) at age 11 and administered the NART and the Mini-Mental State Examination (MMSE) at age 77. A subset (N = 97) were also re-administered the original IQ test. RESULTS: The correlation between NART performance at age 77 and IQ age 11 was high and statistically significant (r = 0.73; P < 0001). This correlation was comparable to the correlation between NART and current IQ, and childhood IQ and current IQ, despite the shared influences on the latter variable pairings. The NART had a significant correlation with the MMSE but this correlation fell to near zero (r = 0.02) after partialling out the influence of childhood IQ. DISCUSSION: The pattern of results provides strong support for the claim that the NART primarily indexes prior (rather than current) intellectual ability.
Aged↗
Problems in using health survey questionnaires in older patients with physical disabilities. The reliability and validity of the SF-36 and the effect of cognitive impairment.
Reliability and validity of the SF-36 Health Survey Questionnaire was assessed in older rehabilitation patients, comparing cognitively impaired with cognitively normal subjects. The SF-36 was administered by face-to-face interview to 314 patients (58-93 years) in the day hospital and rehabilitation wards of a department of medicine for the elderly. Reliability was measured using Cronbach's alpha (for internal consistency) on the main sample and intraclass correlation coefficients on a test-retest sample; correlations with functional independence measure (FIM) were examined to assess validity. In 203 cognitively normal patients (Mini-Mental State Examination > or =24), Cronbach's alpha scores on the eight dimensions of the SF-36 ranged from 0.545 (social function) to 0.933 (bodily pain). The range for the 111 cognitively impaired patients was 0.413-0.861. Cronbach's alpha values were significantly higher (i.e. reliability was better) in the cognitively normal group for bodily pain (P = 0.003), mental health (P = 0.03) and role emotional (P = 0.04). In test-retest studies on a further 67 patients, an intraclass correlation coefficient of 0.7 was attained for five out of eight dimensions in cognitively normal patients, and four out of eight dimensions in the cognitively impaired. Only the physical function dimension in the cognitively normal group attained the criterion level (r > 0.4) for construct validity when correlated with the FIM. In this group of older physically disabled patients, levels of reliability and validity previously reported for the SF-36 in younger subjects were not attained, even on face-to-face testing. Patients with coexistent cognitive impairment performed worse than those who were cognitively normal.
Aged↗
Performance on the Test of Everyday Attention and standard tests of attention following severe traumatic brain injury.
The Test of Everyday Attention (TEA) was designed to address some of the limitations of established measures of attention. However, very few studies have examined its clinical utility. A group of 35 patients who had sustained a severe TBI were compared with 35 age- and education-matched controls on the TEA, Stroop, SDMT, WMS-R Digit Span, Ruff 2s and 7s Selective Attention Test, and PASAT. Of the TEA subtests, only the Map and Telephone Search subtests of the TEA produced significant differences between the two groups, suggesting a deficit in visual selective attention following TBI. Principal components analysis revealed a four-component / factor structure of attention, largely consistent with previous studies. A logistic regression found that the TEA Map Search and Modified Colour-Word subtest of the Stroop were best able to discriminate between the TBI and control groups. When the TBI group was divided into Early ( < 1 year post injury) and Late ( > 2 years post injury) groups, there was an additional deficit on the Lottery (sustained attention) subtest in the Early TBI group, indicating that there is some recovery in attentional function beyond 1 year post injury.
Adult↗
The covert orienting of visual attention following severe traumatic brain injury.
Attentional problems have frequently been identified following traumatic brain injuries (TBIs) using both clinical assessments and self-report measures. Unfortunately, most measures of attention do not enable us to determine the underlying basis of these attentional deficits. One exception is Posner's Covert Orienting of Attention Task (COAT), which is designed to identify some of the fundamental mental operations underlying attention. This study sought to determine whether the COAT task could identify discrete attentional deficits following TBI beyond those caused by reduced speed of information processing. Thirty five patients who had sustained a severe TBI were compared to 35 age-matched controls. Results revealed that, although the reaction times of the patients with TBI were significantly slower than the controls, there were no differences between the two groups in terms of their ability to disengage, move, and engage their attention. The introduction of a secondary (language) task produced no significant difference between the two groups on the COAT task. However, there was a significant difference between the two groups on the language-based task, suggesting a deficit in auditory-verbal attention under dual task conditions.
Adult↗
Neuropsychologic correlates of brain white matter lesions depicted on MR images: 1921 Aberdeen Birth Cohort.
PURPOSE: To examine relationships between brain white matter hyperintensities depicted at magnetic resonance (MR) imaging and performance on neuropsychologic tests in community-dwelling elderly adults. MATERIALS AND METHODS: The 1921 Aberdeen Birth Cohort is a subsample of survivors of the Scottish Mental Survey of 1932 whose mental ability was tested at 11 years of age. Ninety-five of these subjects agreed to undergo brain MR imaging, an examination of general health, and a neuropsychologic evaluation. White matter hyperintensities detected at T2-weighted MR imaging were rated by using a semiquantitative method yielding two continuous variables: white matter lesions and periventricular lesions. Cognitive ability, including crystallized and fluid intelligence domains, was assessed with standard neuropsychologic tests. RESULTS: Rating scores of white matter lesions were normally distributed (on a devised scale) with means of 1.14 for white matter lesions and 1.28 for periventricular lesions. Intra- and interobserver reliability coefficients for scores were high, generally above 0.7. There were significant correlations of medium effect size between the T2-weighted MR imaging-depicted white matter lesions and performance on tests of fluid-type intelligence. No significant correlation was demonstrated between white matter lesion ratings and tests of crystallized intelligence. CONCLUSION: Lower fluid-type ("prevailing") intelligence test scores were associated with increased severity of white matter lesion ratings but not crystallized-type ("premorbid") intelligence test scores. This indicates that MR imaging-depicted white matter lesions are of clinical importance.
Aged↗
Estimating premorbid IQ from demographic variables: a comparison of a regression equation vs. clinical judgement.
OBJECTIVES: To assess the accuracy with which clinicians estimate premorbid IQ from demographic variables and compare it with a regression equation which uses the same information. DESIGN: Repeated measures and correlational. METHODS: Sixty participants were administered the WAIS-R and had their demographic variables recorded (age, sex, years of education and occupation). Eight clinical psychologists estimated the participants' IQs from the demographic variables. Estimated IQs were also obtained using a regression equation developed by Crawford and Allan (1997). RESULTS: The correlation between obtained IQ and the equation-based estimate was significantly higher than the correlation between obtained IQ and the clinicians' estimates. Further, mean estimated IQ from the regression equation did not differ significantly from obtained IQ whereas the means for four of the eight clinicians' estimates did differ significantly. CONCLUSIONS: Demographic-based regression equations can provide unbiased and useful estimates of premorbid IQ; these estimates can be modified in the light of the additional qualitative information available to the clinician.
Adolescent↗
Normative data for the HADS from a large non-clinical sample.
OBJECTIVES: To provide normative data for the Hospital Anxiety Depression Scale (HADS). DESIGN: Repeated measures and correlational. METHODS: The HADS was administered to a non-clinical sample, broadly representative of the general adult UK population (N = 1792) in terms of the distributions of age, gender and occupational status. Correlational analysis was used to determine the influence of demographic variables on HADS scores. RESULTS: Demographic variables had only very modest influences on HADS scores. The reliability of the HADS is acceptable; the Anxiety and Depression scales are moderately correlated (.53). Tables to convert raw scores to percentiles are presented for females and males. CONCLUSIONS: The present normative data allow clinicians to assess the rarity of a given HADS score, and thus provide a useful supplement to existing cut-off scores.
Adolescent↗
The CRABEL score--a method for auditing medical records.
Medical record keeping has become increasingly important particularly for research, audit and medico-legal purposes. The authors present a protocol, the CRABEL score, that is quick and easy to use for the assessment of the quality of medical record keeping with the purpose of standardizing the audit of medical records and improving their quality.
Clinical Protocols↗
Performance on the Modified Card Sorting Test by normal, healthy individuals: relationship to general intellectual ability and demographic variables.
OBJECTIVES: The aim of this study was to obtain normative data for the Modified Card Sorting Test (MCST), and to examine the relationship between performance on this task, general intellectual ability and demographic variables. DESIGN: A sample of 146 healthy individuals was tested with a demographic distribution (age, sex, socioeconomic class) similar to that of the British population. METHODS: The MCST and the Wechsler Adult Intelligence Scales--Revised were administered to 146 people aged between 16 and 75 years. RESULTS: Most people (56.6%) completed six categories, and many people made perseverative errors. Approximately 8% of the participants made over 50% perseverative errors. Performance on the MCST varied with age, years of education and general intellectual ability. Individuals with a Full Scale Intelligence Quotient (FSIQ) below 100 showed much more variability in performance than individuals with an FSIQ over 100. Detailed percentile norms for the performance on different indices of the test are presented. CONCLUSIONS: The performance of individuals on the MCST is more closely associated with general intellectual ability than with demographic variables.
Adolescent↗
Regression equations in clinical neuropsychology: an evaluation of statistical methods for comparing predicted and obtained scores.
Regression equations are widely used in clinical neuropsychology, particularly as an alternative to conventional normative data. In neuropsychological applications the most common method of making inferences concerning the difference between an individual's test score and the score predicted by a regression equation is to multiply the standard error of estimate by an appropriate value of z to form confidence limits around the predicted score. The technically correct method is to calculate the standard error of a new individual Y and multiply it by the value of t corresponding to the desired limits (e.g., 90% or 95%). These two methods are compared in data sets generated to be broadly representative of data sets used in clinical neuropsychology. The former method produces confidence limits which are narrower than the true confidence limits and fail to reflect the fact that limits become wider as scores on the predictor deviate from the mean. However, for many of the example data sets studied, the differences between the two methods were trivial, thereby providing reassurance for those who use the former (technically incorrect) method. Despite this, it would be preferable to use the correct method particularly with equations derived from samples with modest Ns, and for individuals with extreme scores on the predictor variable(s). To facilitate use of the correct method a computer program is made available for clinical practice.
Algorithms↗
Payne and Jones revisited: estimating the abnormality of test score differences using a modified paired samples t test.
Payne and Jones (1957) presented a useful formula for estimating the abnormality of differences between an individual's scores on two tests. Extending earlier work by Sokal and Rohlf (1995) and Crawford and Howell (in press), we developed a modified paired samples t test as an alternative to this formula. Unlike the Payne and Jones formula, the new method treats data from a normative or control sample as sample statistics rather than as population parameters. Technically, the new method is more appropriate for any comparison of an individual's difference score against normative data. However, it is most useful when the normative data is derived from samples with modest Ns; in these circumstances the Payne and Jones method overestimates the abnormality of differences. We suggest that the modified t test can be a useful tool in clinical practice and in single-case research. A computer program is made available that automates the calculations involved and can be used to store relevant data for future use.
Humans↗