Nancy Adams

Executive Functions in Persons with Sleep Apnea

Seventeen patients with sleep apnea syndrome [SAS, Respiratory Disturbance Index (RDI) = 12−85] were compared with 16 normal controls (RDI < 7) on neuropsychological tests of executive functions, a domain in which SAS patients have been suggested to have deficits. SAS patients demonstrated greater deficits in the retrieval of information from semantic memory (Controlled Oral Word Association task) and in shifting responses in the face of error (Wisconsin Card Sort Test), but differences in working memory were not observed. Eliciting deficits in cognitive executive functions in SAS may require more sensitive measures than are typically used in neuropsychiatric research.

Saccadic and Vestibular Abnormalities in Multiple Sclerosis

Determining the effectiveness of treatments for multiple sclerosis (MS) is complicated because of two factors: (1) the clinical course is unpredictable; and (2) the disease may remain active, as evident on MRI, even though neither the patient nor the physician can detect progression.1 Thus, there is a need to improve clinical methods for evaluating patients with MS that extend the system introduced by Kurtzke 40 years ago.2,3 The goal of our study was to determine whether an examination that specifically tests saccades and vestibular eye movements is more sensitive than conventional clinical examinations in identifying brainstem and cerebellar dysfunction in MS.3,4 We examined 50 patients (8 female) with MS seen consecutively in our VA outpatient Neurology Clinic between August 1999 and April 2000. The study was approved by our Institutional Review Board. Kurtzke Functional Neurological Status (FSS) and Expanded Disability Status Scale (EDSS) scores in each patient were based on agreement between two examiners.2,5 We assessed corrected, near visual acuity (Rosenbaum card, expressed as a decimal); visual fields by confrontation; color vision using Ishihara plates (correct responses expressed as decimal of total); pupillary size and reactions; and the presence of optic disc pallor by direct ophthalmoscopy. The eye movements examination consisted of: (1) observing range of movement and covering each eye in turn to test for static ocular alignment; (2) observation of fixation stability in central gaze, and eccentric horizontal, and eccentric vertical gaze; (3) observation of the speed, accuracy, and conjugacy of horizontal and vertical saccades (rapid eye movements) made between two stationary targets (a pencil tip and the examiner’s nose); (4) observation of horizontal and vertical smooth

Evaluation of a model of attention with confirmatory factor analysis.

Structural equation modeling (specifically, analysis of moment structures; J. L. Arbuckle, 1996) was used to evaluate the goodness of fit of a model of components of attention (A. F. Mirsky, B. J. Anthony, C. C. Duncan, M. B. Aheam, & S. G. Kellam, 1991) to neuropsychological test data from 2 samples. One sample consisted of psychiatrically normal persons with and without sleep-disordered breathing, and the other sample consisted of the adults studied by A. F. Mirsky et al. (1991), who gave rise to this model. That sample included psychiatric patients as well as normals. An exploratory data reduction procedure, orincipal-components analysis, suggested that attention night be conceptualized as composed of 4 independent elements or components: focus-execute, sustain, shift, and encode. Neither the proposed orthogonal model nor a model permitting correlated factors adequately fit either data set, suggesting that these 4 attention constructs are as yet not clearly validated in the measures used to assess them.

Abnormal eye movements predict disability in MS: two-year follow-up

Abstract: We conducted a two‐year follow‐up study of 40 patients with MS in whom we had reported that abnormal eye movements (AEM) were associated with greater general disability. AEM patients (17/40) remained significantly (p < .001) more disabled (median EDSS of 7.0) than those with normal eye movements (median EDSS of 5.0). AEM and great disability were associated with abnormal MRI signals in brainstem or cerebellum, where disease may involve control circuits for eye movements as well as descending motor pathways.

Estimating premorbid intelligence in African-American and white elderly veterans using the american version of the National Adult Reading Test

Knowledge of earlier intellectual functioning can be very helpful in the diagnosis of neurocognitive disorders. The National Adult Reading Test (Nelson, 1982), based on the observation that reading irregularly spelled words remains intact in mild dementia, may be useful for this purpose. A version for speakers of American English (AMNART) was recently published (Grober & Sliwinski, 1991). The present study evaluated the validity of the AMNART with demented and nondemented African-American and White elderly veterans. The average differences between African-American and White participants on the AMNART and WAIS-R were similar. The differences between demented and nondemented patients were greater on the WAIS-R than on the AMNART, as expected. Paradoxically, the AMNART appears to over-estimate IQ among nondemented individuals with lower WAIS-R scores, but underestimate IQ among more impaired demented patients. Using Grober and Sliwinskis (1991) 10-point discrepancy rule between AMNART and WAIS-R VIQ scores, 70% of demented and nondemented veterans were successfully classified. No discontinuation rule for the AMNART could be established because word difficulty order varies across samples.

Comparability of the Rey and Mack forms of the Complex Figure Test.

Equivalent versions of the Complex Figure Test (CFT) are useful for assessing change over time in constructional skills, planning, spatial organization, and visual-spatial memory while minimizing practice effects. To address the need for an equivalent version of the CFT to the Rey, the present study compared copy and 45min-delayed recall accuracy scores of the Rey and Mack CFTs obtained from 245 adults involved in a study of the neuropsychological correlates of sleep apnea and its treatment. Accuracy scores did not significantly differ between individuals with and without sleep apnea. Also, there was no significant difference between copy or recall accuracy scores obtained on the Rey and Mack CFTs. Similar correlations were found between relevant demographic factors, estimated IQ, and accuracy scores for both CFTs. These data suggest that the Mack figure may be a useful alternative to the Rey CFT.

Probing the mechanism of saccade-associated head movements through observations of head movement propensity and cognition in the elderly

Humans may accomplish gaze shifts by eye-only saccades or combined eye–head saccades. The mechanisms that determine whether the head moves remain poorly understood. Many observations can be explained if phylogenetically ancient circuits generate eye–head saccades by default and frontal cerebral structures interrupt this synergy when eye-only saccades are preferable. Saccade-associated head movements have been reported to increase in the elderly. To test the hypothesis of frontal inhibition of head movements, we investigated whether the increase is associated with a decline in frontal cognitive function. We measured head movement tendencies and cognition in volunteers aged 61–80. Measures of head movement tendency included the customary range of eye eccentricity, customary range of head eccentricity, range of target eccentricities evoking predominantly eye-only saccades, and two measures of head amplitude variation as a function of target eccentricity. Cognitive measures encompassed verbal fluency, verbal memory, non-verbal memory, and executive function. There was no correlation between cognition and any measure of head movement tendency. We combined these elderly data with measurements of head movements in a group aged 21–67 and found mildly reduced, not increased, head movement tendencies with age. However, when confronted with a task that could be accomplished without moving the head, young subjects were more likely to cease all head movements. While inconclusive regarding the hypothesis of inhibition of saccade-associated head movements by cerebral structures, the results indicate the need to distinguish between mechanisms that define head movement tendencies and mechanisms that adapt head motion to the geometry of a specific task.

Relation of Aphemia and Agraphia

A 49-year-old right-handed man presented with a severe impairment of motor speech output aphemia. Initially, he could make grunting sounds, but was otherwise mute. There was no disturbance of comprehension, and he preferred to communicate by writing. Writing was agrammatic with lexical errors and mispellings which improved with the speech disturbance. The writing abnormalities of aphemics emphasize the aphasic nature of this speech abnormality.