David C. Osmon

A double-blind controlled study of methylphenidate treatment in closed head injury

Closed head injuries (CHI) may produce permanent, disabling changes in cognitive functions and social behaviour. Recent clinical case reports have suggested that stimulant medications may improve neurobehavioural functioning in CHI patients. In the present study, we evaluated the effects of methylphenidate (0.3 mg/kg b.i.d.) in 12 chronic CHI patients (14 to 108 months post-injury) using a double-blind, placebo-controlled, randomized, crossover design. Outcome measures consisted of cognitive tests of attention, learning and cognitive processing speed. In addition, a rating scale was completed by a close friend or relative to assess social behaviour. No significant differences were found between drug and placebo conditions on any of the neurobehavioural measures. These data do not support the clinical use of methylphenidate in the treatment of CHI patients.

The Role of Left Occipitotemporal Cortex in Reading: Reconciling Stimulus, Task, and Lexicality Effects

Although the left posterior occipitotemporal sulcus (pOTS) has been called a visual word form area, debate persists over the selectivity of this region for reading relative to general nonorthographic visual object processing. We used high-resolution functional magnetic resonance imaging to study left pOTS responses to combinatorial orthographic and object shape information. Participants performed naming and visual discrimination tasks designed to encourage or suppress phonological encoding. During the naming task, all participants showed subregions within left pOTS that were more sensitive to combinatorial orthographic information than to object information. This difference disappeared, however, when phonological processing demands were removed. Responses were stronger to pseudowords than to words, but this effect also disappeared when phonological processing demands were removed. Subregions within the left pOTS are preferentially activated when visual input must be mapped to a phonological representation (i.e., a name) and particularly when component parts of the visual input must be mapped to corresponding phonological elements (consonant or vowel phonemes). Results indicate a specialized role for subregions within the left pOTS in the isomorphic mapping of familiar combinatorial visual patterns to phonological forms. This process distinguishes reading from picture naming and accounts for a wide range of previously reported stimulus and task effects in left pOTS.

Processing abilities associated with math skills in adult learning disability.

This study evaluated college adults (N = 138) referred for learning problems using a Cattell-Horn-Carroll based intelligence measure (Woodcock Johnson-Revised: WJ-R) and spatial and executive function neuropsychological measures to determine processing abilities underlying math skills. Auditory and visual perceptual (WJ-R Ga and Gv), long- and short-memory (WJ-R Glr and Gsm), crystallized and fluid intellectual (WJ-R Gc and Gf), and spatial and executive function (Judgment of Line Orientation [JLO] and Category Test) measures differentiated those with and without math deficits. Multiple regression revealed selective processing abilities (Gf, JLO, and Category) predicting about 16% of the variance in math skills after variance associated with general intelligence (also about 16%) was removed. Cluster analysis found evidence for a selective spatial deficit group, a selective executive function deficit group and a double deficit (spatial and executive function) group. Results were discussed in relation to a double deficit hypothesis associated with developmental dyscalculia.

Inspection time and IQ Fluid or perceptual aspects of intelligence

Abstract Past research has found an association between inspection time (IT) and fluid intelligence using measures confounded with visual processing (e.g., Wechsler PIQ or Ravens Progressive Matrices). The present study related IT to intelligence using a measure (Woodcock–Johnson—Revised, WJ-R) that has nonconfounded factors of mental ability in order to determine whether the association is based upon fluid IQ or perceptual processes. Thirty-seven undergraduate students were given fluid, crystallized, and visual processes subtests from the Woodcock–Johnson and a visual IT task. Stepwise multiple regression and partial correlations revealed that IT was related only to fluid intelligence (range corrected correlation of −.74), supporting the notion that IT reflects some fundamental underlying aspect of intelligence such as neural processing efficiency.

The Word Reading Test of Effort in Adult Learning Disability: A Simulation Study

The Word Reading Test (WRT) was designed to detect effort problems specific to a learning disability sample. The WRT and the Word Memory Test (WMT) were administered to two simulator and normal control groups. The WRT showed excellent receiver operating characteristics (e.g., 90% sensitivity and 100% positive predictive power) and outperformed the WMT in detecting both reading and mental speed simulators. This finding and a double dissociation between reading and speed simulators on WRT errors and reaction time suggested specific effort effects while poor effort of simulators on the WMT suggested general effort effects. Results are supportive of the WRT as a potential effort indicator in learning disability.

Minnesota Multiphasic Personality Inventory Correlates of Neuropsychological Deficits

The present study was designed to investigate the relationships between various neuropsychological deficits and patterns of personality variables. Fifty individuals with medically verified brain lesions had 8 tests administered as part of a larger neuropsychological assessment. Individual relationships between each of the 8 neuropsychological variables and each of the 13 clinical and validity scales of the MMPI were analyzed by means of t-tests and Pearson correlations. Multiple regression and discriminant analysis were used to assess complex relationships between the neuropsychological variables and the MMPI scales. Results of these procedures showed a relative lack of individual relationships between cognitive and personality variables, although there were strong correlations between patterns of personality variables and neuropsychological performance. Each neuropsychological deficit manifested a strong characteristic MMPI profile. Traditional personality differences associated with laterality of lesion...

Neuropsychological Evaluation in the Diagnosis and Treatment of Tourette’s Syndrome:

The neurobiological basis of Tourette’s syndrome is reviewed for the purpose of presenting a clinically relevant account of the neuropsychology of the disorder for the clinician who is behaviorally oriented. The neuropathology and neuropsychological deficits typically found in Tourette’s are reviewed, and a neuropsychological test battery is described that can be used to help characterize the clinical presentation of the disorder. Although Tourette’s syndrome is ultimately diagnosed by behavioral criteria, characterizing the cognitive deficits (or lack thereof) associated with the disorder is integral to fully appreciating the challenges posed by the disorder in any given case. The variety of cognitive deficits associated with Tourette’s is reviewed to show the importance of the neuropsychological evaluation in differential diagnostic, therapeutic, and prognostic decisions.

Factor Analysis of the Luria-Nebraska Neuropsychological Battery: I. Motor, Rhythm, and Tactile Scales

In recent years, Golden and his associates have devised and presented a standardized version of Lurias neuropsychological examination. One of the main advantages of this battery over Lurias more qualitative approach is the possibility of examining a number of the theoretical statements made by Lauria concerning the relationship of basic psychological skills which make up the tests in each of ten major areas of neuropsychological function. The present paper is an initial attempt to examine some of the interrelationships among items on the standardized battery and to compare these to Lurias theoretical structures. To do this the Luria-Nebraska Neuropsychological Battery was administered to a mixed neurological, psychiatric and normal population of 272 individuals. From the results of study of these patients, principle axis factor analyses with communalities on the diagonal) were done on three scales (Motor, Rhythm, Tactile) and obliquely rotated to the simplest solution. The resulting factors were found, in general, to conform to the factors predicted by Lurias theory. The interpretation of each factor found is discussed, as well as its implication. Future papers are planned to deal with the factor structure of further scales on the standardized battery.

Factor analysis of the Luria-Nebraska neuropsychological battery. II: Visual, receptive, expressive and reading scales.

In recent years, Golden and his associates have devised and presented a standardized version of Lurias neuropsychological examination. One of the main advantages of this battery over Lurias more qualitative approach is the possibility of examining a number of the theoretical statements made by Luria concerning the relationship of basic psychological skills which make up the tests in each of ten major areas of neuropsychological function. The present paper is the second in a series attempting to examine some of the interrelationships among items on the standardized battery and compare these to Lurias theoretical structures. To do this, the Luria-Nebraska Neuropsychological Battery was administered to a mixed neurological, psychiatric and normal population of 272 individuals. From the results of these tests, principle axis factor analyses (with communalities on the diagonal) were done on four scales (Visual, Expressive, Receptive, Reading) and obliquely rotated to the simplest solution. The resulting factors were found generally to conform to the factors predicted by Lurias theory. The interpretation of each factor found is discussed, as well as its implication.

Relationship of Age and Education to Performance on A Standardized Version of Luria's Neuropsychological Tests in Different Patient Populations

A.R. Luria, a Russian neuropsychologist, developed many qualitative bedside tests that have been effective in the diagnosis and localization of neurological disorders. Recently, a standardized and objectively-scored version of Lurias tests has been developed. Knowledge of the effects of patient age and education on neuro-psychological test performance has been found crucial in the neurodiagnostic decision-making process. The present study examined the effects of patient age(younger subjects between 20 and 40 years and older subjects between 50 and 70 years of age), education (grade school, high school, and post-high school), and diagnosis (normal, schizophrenic, brain damaged) on 14 standardized Luria measures. A weighted means analysis of variance found 11 significant age effects, 14 significant educational effects, and 14 significant effects diagnosis. One significant interaction was found between education and diagnosis, the results support the contention that with appropriate age and educational corrections, the standardized Luria battery would satisfy the need for a short, objectively scored, and diagnostically effective neuropsychological battery.