Biomedical subjects

S R Millis

Publications and source records attributed to S R Millis.

At least 19 recordsLinked to original sources

PubMed2004

Detecting incomplete effort on the MMPI-2: an examination of the Fake-Bad Scale in mild head injury.

The current study is an investigation of the MMPI-2 Fake Bad Scale ( FBS ) in the detection of incomplete effort in mild head injury (MHI). Using ROC curve analysis, we found that a cutoff score of 21 had a sensitivity of 90% and specificity of 90%, providing an overall correct classificatory rate of 90%. In addition, traditional indices of faking bad on the MMPI-2, the F and F-K indices, fared relatively poorly by comparison and added no predictive power over the FBS. Finally, multivariate analyses revealed that although the FBS shares a number of items with Hs and Hy scales, the FBS carried the majority of variance in predicting incomplete effort in our MHI sample. Overall, these findings indicate that the FBS has high sensitivity and specificity in identifying incomplete effort in mild head injury.

Adult↗

PubMed2003

Spacing of repetitions improves learning and memory after moderate and severe TBI.

Extensive research has determined that new learning in healthy individuals is significantly improved when trials are distributed over time (spaced presentation) compared to consecutive learning trials (massed presentation). This phenomenon known as the "spacing effect" (SE) has been shown to enhance verbal and nonverbal learning in healthy adults of different ages and in different memory paradigms (e.g., recognition, recall, etc.). The purpose of this study was to examine whether learning in adults with moderate and severe traumatic brain injury (TBI) is improved using a spacing-of-repetitions procedure. Using a within-groups design, participants with TBI (n = 20) were presented a list of 115 words that were presented either once (single condition), twice consecutively (massed condition), or twice with 11 words between presentations (spaced condition). Participants were required to rank each word from 1 to 10 according to their familiarity with the word; they were not asked to "memorize" words for a later test. Word list learning was measured with a free recall test immediately following list presentation and with free recall and recognition tests after a 30-min delay. Participants recalled and recognized significantly more spaced words than massed words during this word list learning task. These results strongly indicate that the spacing of repetitions improves learning and memory in individuals who have sustained moderate to severe TBI. Implications for rehabilitation are discussed.

Adolescent↗

PubMed2001

Severe penetrating head injury: a study of outcomes.

OBJECTIVE: To determine and describe the demographics and functional outcomes of persons who require inpatient rehabilitation for severe penetrating head injury resulting from a gunshot wound to the head. DESIGN: Data were collected prospectively from the time of admission to acute care through discharge from inpatient rehabilitation. SETTING: Two sites: an urban, level I, acute care, trauma center and an inpatient rehabilitation hospital with a specialized brain injury unit. PARTICIPANTS: Twenty-seven persons with severe penetrating head injury. MAIN OUTCOME MEASURES: The FIM instrument, the Disability Rating Scale (DRS), and the length of stay (LOS). RESULTS: Demographic data showed our population to be similar to other groups of persons at high risk for violent injury. Eighty-five percent of the subjects were men with a mean age of 34 years. The majority were African American (93%), reflective of our general patient population. Average acute care LOS was 31 days and average rehabilitation LOS was 44 days. Average FIM gain was 40.2 and, on average, DRS scores improved 7.6 points from rehabilitation admission to discharge. All study participants made enough progress to be discharged to private residences. CONCLUSION: Although the mortality rate is high among patients with penetrating head injury, those who survive to receive inpatient rehabilitation can achieve functional improvement.

Activities of Daily Living↗

PubMed2001

Using early neuropsychologic testing to predict long-term productivity outcome from traumatic brain injury.

OBJECTIVE: To evaluate whether early neuropsychologic testing is useful in predicting long-term productivity outcome after traumatic brain injury (TBI). DESIGN: Validation cohort prediction study. SETTING: Four inpatient brain injury rehabilitation programs participating in the Traumatic Brain Injury Model Systems project. PARTICIPANTS: A total of 293 adults with nonpenetrating TBI. MAIN OUTCOME MEASURES: Fifteen neuropsychologic tests were administered to patients who emerged from posttraumatic amnesia before rehabilitation discharge. Test scores were classified in the normal range or impaired range, using objective criteria. Outcome was defined as productive if the patient was competitively employed or enrolled full time in regular education. RESULTS: Productivity at follow-up was predicted by completion of at least 1 neuropsychologic test before discharge, by an injury-test interval of less than 2 months, and by normal range scores on 10 of the 15 neuropsychologic tests. Normal range scores on these tests increased the probability of a productive outcome by 40% to 130%. CONCLUSIONS: Neuropsychologic testing can help predict long-term productivity even when performed before discharge from inpatient rehabilitation and at variable injury-test intervals. Early testing should be interpreted in relation to injury-test interval. Because tests of multiple neuropsychologic domains predicted outcome, comprehensive evaluations might be more useful in predicting outcome.

Adult↗

PubMed2001

Verbal recall and recognition following traumatic brain injury: a [0-15]-water positron emission tomography study.

Although several studies exist which have examined static functional neuroimaging following traumatic brain injury (TBI), controlled cognitive activation studies of episodic memory in this population have not been published. The present investigation studied verbal recall using [O-15]-water positron emission tomography (PET) in 5 individuals who sustained severe TBI (M GCS=6.8; M years post-injury=3.18), and 4 non-injured control participants. Statistical image analysis demonstrated changes in frontoparietal regional cerebral blood flow (rCBF) in both groups, but there were interesting differences between groups and across conditions. Frontal lobe rCBF changes in TBI patients were reduced during free recall but enhanced during recognition, when compared to controls. Changes in cerebellar rCBF were observed in the control group during free recall, but not in the TBI sample. In both groups, bifrontal rCBF increases were noted on recognition tasks. The present findings provide evidence of alterations in specific substrates involved in verbal recall following brain injury.

Adult↗

PubMed2001

Assessment of response bias in mild head injury: beyond malingering tests.

The evaluation of response bias and malingering in the cases of mild head injury should not rely on a single test. Initial injury severity, typical neuropsychological test performance patterns, preexisting emotional stress or chronic social difficulties, history of previous neurological or psychiatric disorder, other system injuries sustained in the accident, preinjury alcohol abuse, and a propensity to attribute benign cognitive and somatic symptoms to a brain injury must be considered along with performances on specific measures of response bias. This article reviews empirically-supported tests and indices. Use of the likelihood ratio and other statistical indicators of diagnostic efficiency are demonstrated. Bayesian model averaging as a statistical technique to derive optimal prediction models is performed with a clinical data set.

Algorithms↗

PubMed2001

Effects of the routine change of chronic indwelling Foley catheters in persons with spinal cord injury.

OBJECTIVE: To determine whether routine catheter changes have any effect on the urinary white blood cell count (WBC) and bacterial culture in asymptomatic individuals with spinal cord injury (SCI) who have indwelling Foley catheters. DESIGN: Prospective case series. SETTING: Urology and SCI outpatient departments of a rehabilitation center. SUBJECTS: Twelve asymptomatic individuals (male and female) with SCI who have chronic indwelling urethral Foley catheters that are changed routinely every month. MAIN OUTCOME MEASURES: Two sets of urinalysis and urinary culture and sensitivity from each individual, one set taken through the Foley catheter before the catheter change and another set after the catheter change. WBC, bacterial identity, and colony count were measured, and the corresponding data were compared. RESULTS: All subjects had pyuria and bacteriuria before and after the catheter change. Analysis of the data showed a statistically significant increase in WBC in the urine after the indwelling Foley catheter was changed (P = .0039). However, bacterial types and corresponding colony counts remained almost completely unchanged. CONCLUSIONS: Routine change of chronic indwelling Foley catheters in asymptomatic individuals with SCI causes a significant rise in the urinary WBC, without altering the bacterial identity or colony count. Pyuria and bacteriuria are prevalent among individuals with SCI (including those who are asymptomatic) with indwelling Foley catheters. This study suggests that urinalysis should be taken before a catheter change.

Bacteriological Techniques↗

PubMed2001

Long-term neuropsychological outcome after traumatic brain injury.

OBJECTIVE: To describe neuropsychological outcome 5 years after injury in persons with traumatic brain injury (TBI) who received inpatient medical rehabilitation. To determine the magnitude and pattern neuropsychological recovery from 1 year to 5 years after injury. DESIGN: Longitudinal cohort study with inclusion based on the availability of neuropsychological data at 1 year and 5 years after injury. SETTING: National Institute on Disability and Rehabilitation Research Traumatic Brain Injury Model Systems of Care. PARTICIPANTS: One hundred eighty-two persons with complicated mild to severe traumatic brain injury. PRIMARY OUTCOME MEASURES: Digits Forward and Backward, Logical Memory I and II, Token Test, Controlled Oral Word Association Test, Symbol Digit Modalities Test, Trail Making Test, Rey Auditory Verbal Learning Test, Visual Form Discrimination, Block Design, Wisconsin Card Sorting Test, and Grooved Pegboard. RESULTS: Significant variability in outcome was found 5 years after TBI, ranging from no measurable impairment to severe impairment on neuropsychological tests. Improvement from 1 year after injury to 5 years was also variable. Using the Reliable Change Index, 22.2% improved, 15.2% declined, and 62.6% were unchanged on test measures. CONCLUSIONS: Neuropsychological recovery after TBI is not uniform across individuals and neuropsychological domains. For a subset of persons with moderate to severe TBI, neuropsychological recovery may continue several years after injury with substantial recovery. For other persons, measurable impairment remains 5 years after injury. Improvement was most apparent on measures of cognitive speed, visuoconstruction, and verbal memory.

Adult↗

PubMed2000

Factors associated with insomnia among post-acute traumatic brain injury survivors.

This study investigated the relationships between insomnia and select demographic, injury and psychosocial variables in post-acute, traumatic brain injury. Clinical assessment of sleep and mood was undertaken via objective measures and a diagnostic interview among 91 consecutive brain injury admissions to an outpatient neurorehabilitation clinic. No associations between insomnia and gender, education, age, and time since injury were found. A logistic regression model of insomnia prediction based upon the Beck Depression Inventory (BDI), self-reported pain disturbance, litigation and Glasgow Coma Score (GCS) correctly classified 87% of the sample with respect to the presence or absence of insomnia; however, depression and injury severity were the only variables that made a significant unique contribution to the prediction of insomnia. It is concluded that among post-acute traumatic brain injury patients, insomnia is linked with both the presence of depression and a history of milder brain injuries. This suggests that the determinants of insomnia may differ from the acute to the post-acute phase, with neurological factors playing a primary role early in the recovery process and psychosocial factors ascending later. Therefore, assessment and treatment of insomnia must give careful attention to the larger psychosocial context in which the sleep disorder emerges, particularly to role of emotional disturbance.

Adolescent↗

PubMed2000

Diagnostic efficiency and material specificity of the Warrington Recognition Memory Test: a collaborative multisite investigation.

Two studies examined the Warrington Recognition Memory Test (RMT) discrepancy index (Words-Faces) in a large sample of patients heterogeneous with respect to age, education, gender, and neurological diagnosis. In Study 1 (N = 504) we used cutoffs from the Words-Faces discrepancy scores derived from Warrington's original validation sample to attempt to accurately classify patients with left, right, or diffuse brain damage. Sensitivity for left hemisphere patients (Faces > Words) was 10% with a specificity of 88%, whereas sensitivity for right hemisphere patients (Words > Faces) was 48% with a specificity of 86%. For patients with diffuse brain damage (Words = Faces) sensitivity was 69% and specificity was 38%. In Study 2 (N = 263), we examined the relationship between the Words-Faces discrepancy score and Wechsler Memory Scale-Revised (WMS-R; Wechsler, 1981) Logical Memory and Visual Reproduction subtests. Contrary to predictions, patients with Words > Faces performed better on both WMS-R subtests; the Faces > Words discrepancy was not related to Visual Reproduction performance. Potential reasons for these negative findings are discussed, as well as cautions for future RMT discrepancy index use.

Journal Article↗

PubMed1999

Measures of executive functioning as predictors of functional ability and social integration in a rehabilitation sample.

OBJECTIVE: To examine the utility of executive function tests in predicting rehabilitation outcome. DESIGN: A prospective, descriptive study of the value of neuropsychologic and motor functioning measures in the prediction of functional outcome 6 months after acute rehabilitation. SETTING: A Midwestern, urban, university-affiliated rehabilitation hospital. PATIENTS: Ninety consecutive admissions to traumatic brain injury, orthopedic, and spinal cord injury units. Age of the participants ranged from 17 to 73. MAIN OUTCOME MEASURES: Community Integration Questionnaire (CIQ), Disability Rating Scale (DRS), SF-36 Health Survey. RESULTS: Canonical correlation analyses indicated that measures of executive functioning and verbal memory were strongly related to measures of functional outcome 6 months after rehabilitation, as measured by the DRS and the CIQ. In contrast, perceived health status as measured by the SF-36 was highly related to estimated premorbid IQ and modestly related to visuospatial impairment. CONCLUSIONS: Executive functioning, verbal memory, and estimated premorbid intelligence predict functional dependence after discharge from rehabilitation beyond information regarding basic sensory and motor skills. Moreover, there is a dissociation between measures of functional outcome, such that objective and behaviorally oriented measures of disability (CIQ and DRS) are strongly related to each other; however, they are not related to perceptions of general health status (SF-36).

Adolescent↗

PubMed1999

Confirmatory factor analysis of the Wechsler Memory Scale-III.

The latent structure of the Wechsler Memory Scale-III was analyzed by confirmatory factor analysis using the covariance matrix based on the 11 primary subtests from the standardization sample. Omnibus fit indexes and individual parameter estimates were examined. Of the five models evaluated, a three-factor model (working memory, auditory memory, and visual memory) provided the best fit for the standardization sample (NNFI = .98, RMSEA = .05, GFI = .98, BIC = 429.42). Models that proposed separate immediate and delayed memory constructs were hampered by inadmissible parameter estimates that signaled model specification errors. R2 values for the Faces subtests were uniformly low for all five models that suggested that this subtest has insufficient commonality with the visual memory construct.

Factor Analysis, Statistical↗

PubMed1999

The effect of cocaine on traumatic brain injury outcome: a preliminary evaluation.

The effect of acute cocaine use on the functional and neuropsychological outcome of persons with traumatic brain injury, (TBI) was examined by comparing persons with TBI who tested positive for cocaine at the time of admission with persons with negative drug and alcohol screens. Subjects were matched for age, admission GCS score, level of education, and aetiology of injury (closed vs penetrating head injury). Dependent measures were: the Disability Rating Scale, the Functional Independence Measure, and selected neuropsychological tests. No group differences were found in DRS, FIM, FIM subsets, or FIM change. However, the cocaine group scored significantly lower than the no-drug group on the Rey Auditory Verbal Learning Test, but did not differ on any of the other neuropsychological tests.

Adolescent↗

PubMed1998

Executive functioning and predictors of falls in the rehabilitation setting.

OBJECTIVE: To examine the incremental utility of executive function tests in the prediction of inpatient falls. DESIGN: Evaluation of neuropsychologic and medical risk factors for fall was completed at admission. Inpatient falls were tabulated following discharge. SETTING: A freestanding, urban rehabilitation hospital. PATIENTS: Ninety consecutive admissions to traumatic brain injury, orthopedic, and spinal cord injury wards. Age of the participants ranged from 17 to 73 years old. MAIN OUTCOME MEASURE: Incident reports of inpatient falls. RESULTS: Standard multiple regression analyses indicated that measures of executive functioning sensitive to self-monitoring accounted for unique variance in falls beyond that explained by age and functional motor ability as assessed by the Functional Independence Measure. Visuospatial functioning, although not directly related to falls, was a significant predictor in combination with measures of executive functioning. Together, these variables accounted for 30.3% of the variance in inpatient falls (multiple r = .55; p < .001). CONCLUSION: The findings suggest that the influence of motor and sensory impairments on falls are moderated, in part, by executive functioning. Patients with intact executive functioning are less likely to act in ways that could result in a fall; thus, aggressive fall prevention measures may be unnecessary. In contrast, executive dysfunction may signal the need for intervention, even among patients whose profiles are unremarkable with regard to traditional risk factors for fall.

Accidental Falls↗

PubMed1998

Detection of incomplete effort on the Wechsler Adult Intelligence Scale-Revised: a cross-validation.

This study determined whether the Vocabulary-Digit Span difference score and discriminant function based on subtests of the Wechsler Adult Intelligence Scale-Revised (WAIS-R) developed by Mittenberg et al. (1995) could differentiate patients with moderate and severe traumatic brain injuries (n = 50) from persons with financially compensable mild head injuries who were giving incomplete effort (n = 50). Employing modified cutoff scores, the discriminant function and Vocabulary-Digit Span difference score accurately classified 90% and 79% of the cases, respectively. Persons with traumatic brain injuries may produce WAIS-R subtest patterns that can be differentiated from individuals showing incomplete effort. These WAIS-R algorithms appear useful in making that distinction.

Adult↗

PubMed1998

Effects of coaching on detection of malingering on the California Verbal Learning Test.

The diagnostic accuracy of California Verbal Learning Test (CVLT) indices to detect malingered head injury was examined using a simulation paradigm that included naive malingerers, malingerers provided with information about head injury, and normal controls (N = 90). The application of diagnostic cutoff scores for Recognition Discriminability and Recognition Hits derived from populations of individuals with bona fide head injury and individuals suspected of malingering (Millis et al., 1995) proved highly sensitive and modestly specific in detecting feigned head injury among both simulation groups. Results of analyses of variance and logistic regression support previous findings that malingerers overestimate memory impairment associated with mild head injury; however, they indicate that exposure to a simple instructional set may render insensitive many indices of malingering. In contrast, indices based on more subtle principles of learning theory hold promise in the detection of malingering, even in the presence of an instructional set.

Adolescent↗

PubMed1998

Validation of the Warrington theory of visual processing and the Visual Object and Space Perception Battery.

Competing hypotheses regarding the nature of visual processing were examined using the performance of 111 healthy older persons on the Warrington and James (1990) Visual Object and Space Perception Battery (VOSP). Confirmatory factor analysis indicated that a two-factor model corresponding to the Warrington theory of object and space perception as discrete domains showed excellent congruence with the data, despite limitations in the VOSP space perception tests that may have resulted in underestimation of model fit. Moreover, compared to a unidimensional model of visual processing, the Warrington model demonstrated a superior fit to the data. These findings add to the bodies of evidence supporting a dissociation between object- and space-perception abilities and defining the construct validity of the VOSP battery.

Aged↗

PubMed1998

Do calendars enhance posttraumatic temporal orientation?: a pilot study.

The purpose of this study was to determine the effectiveness of an in-room calendar to correct temporal disorientation in a brain-injured population. Thirty consecutive brain injured patients (16 traumatic, 14 non-traumatic) admitted to a brain injury rehabilitation unit were randomly assigned to either a group with in-room calendars (n = 14) or a group without calendars (n = 16). A baseline Temporal Orientation Test (TOT) score was obtained. Daily TOT scores were obtained for patients throughout their rehabilitation stay or until two consecutive normal scores were obtained. When orientation errors were made, they were corrected and the attention of the patient was drawn to the calendar. There were no statistically significant associations between group and age, gender or mean GCS (for patients with traumatic etiology). Only baseline length of post-traumatic amnesia (PTA) had a significant association with eventual emergence from PTA (as defined by a normal score on the TOT). Age and presence of calendar were not significant. In-room calendars have been espoused as orientation aides. The data from this pilot study suggest that calendars do not hasten re-orientation. This finding suggests that other widely held but not rigorously tested beliefs regarding cognitive rehabilitation may need to be examined.

Age Factors↗