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Anna M Barrett

Publications and source records attributed to Anna M Barrett.

At least 19 recordsLinked to original sources
PubMed2006

Cognitive rehabilitation interventions for neglect and related disorders: moving from bench to bedside in stroke patients.

The spatial neglect syndrome, defined by asymmetric attention and action not attributed to primary motor or sensory dysfunction and accompanied by functional disability, is a major cause of post-stroke morbidity. In this review, we consider the challenges and obstacles facing scientific researches wishing to evaluate the mechanisms and effectiveness of rehabilitation interventions. Spatial neglect is a heterogeneous disorder, for which consensus research definitions are not currently available, and it is unclear which of the deficits associated with the syndrome causes subsequent disability. We review current opinion about methods of assessment, suggest a rational approach to selecting therapies which requires further study, and make systems-level and theoretical recommendations for building theory. We lastly review some creative questions for consideration in future research.

Animals↗
PubMed2005

Unawareness of cognitive deficit (cognitive anosognosia) in probable AD and control subjects.

OBJECTIVE: To develop a quantitative method of assessing cognitive anosognosia in six cognitive and two noncognitive domains. METHODS: Control (n = 32) and probable Alzheimer disease (pAD) (n = 14) subjects self-estimated memory, attention, generative behavior, naming, visuospatial skill, limb praxis, mood, and uncorrected vision, both before and after these abilities were assessed. Based on this estimate and their performance the authors calculated an anosognosia ratio (AR) by dividing the difference between estimated and actual performance by an estimated and actual performance sum. With perfect awareness, AR = 0. Overestimating abilities would yield a positive AR (< or =1); underestimation would yield a negative AR (> or =-1). RESULTS: Relative to controls, pAD subjects demonstrated anosognosia. Pre-testing (off-line), pAD subjects overestimated their visuospatial skill; post-testing (on-line), pAD subjects overestimated their memory. Control subjects also made self-rating errors, underestimating their attention pre-testing and overestimating limb praxis and vision post-testing. CONCLUSIONS: This anosognosia assessment method may allow more detailed examination of distorted self-awareness. These results suggest that screening for anosognosia in probable Alzheimer disease (pAD) should include self-estimates of visuospatial function, and that, in pAD, it may be useful to assess anosognosia for amnesia both before and after memory testing.

Aged↗
PubMed2005

Is it Alzheimer's disease or something else? 10 disorders that may feature impaired memory and cognition.

Patients who have the classic combination of progressive memory loss and problems retrieving stored knowledge that is characteristic of Alzheimer's disease may actually have another, treatable disorder. In these cases, appropriate evaluation can reveal the true diagnosis and guide therapy to stabilize or improve thinking and avert other complications. In this article, Dr Barrett explores 10 conditions that may be mistaken for Alzheimer's disease.

Aged↗
PubMed2004

Eye patching biases spatial attention after thalamic hemorrhage in a patient without spatial neglect: a case report.

Monocular patching has been advocated as a treatment for spatial neglect. Eye patching, however, is also reported to increase spatial bias. Thus, patching brain injury patients for ocular conditions may also impair their attention. To learn if an eye patch may induce asymmetric attention in a patient without spatial neglect, we tested a woman with diplopia after a left thalamic-intraventricular hemorrhage. She had no spatial neglect on bedside attention tasks. Using a laser pointer, she bisected a blank space at near (279 mm) and far (914 mm) distances under 3 conditions: unpatched and wearing a right or left eye patch. Unpatched, she showed no bias. She erred further leftward with right patching at both distances. Right eye patching appeared to induce neglect of right space when the patient performed this task. With left patching, leftward error tended to increase in near space only. Clinicians prescribing eye patches to patients with brain injury even for purely ocular indications, should evaluate them for spatial neglect once the patch is in place.

Adult↗
PubMed2003

Ipsilateral neglect versus hemianopic compensation.

Hemianopic patients may make line bisection errors in the direction of contralesional space, which could represent functional compensation or might be due to ipsilateral neglect. The authors report a patient with stroke with left homonymous hemianopsia and contralesional (leftward) bias on the line bisection task while upright, lying on his left side, and sitting with head bent 90 degrees leftward. Because hemianopic compensation should map retinotopically and the patient consistently erred body-leftward, the authors conclude that his contralesional errors are consistent with ipsilateral neglect.

Brain↗
PubMed2003

Mental object rotation in Parkinson's disease.

Deficits in visual-spatial ability can be associated with Parkinson's disease (PD), and there are several possible reasons for these deficits. Dysfunction in frontal-striatal and/or frontal-parietal systems, associated with dopamine deficiency, might disrupt cognitive processes either supporting (e.g., working memory) or subserving visual-spatial computations. The goal of this study was to assess visual-spatial orientation ability in individuals with PD using the Mental Rotations Test (MRT), along with other measures of cognitive function. Non-demented men with PD were significantly less accurate on this test than matched control men. In contrast, women with PD performed similarly to matched control women, but both groups of women did not perform much better than chance. Further, mental rotation accuracy in men correlated with their executive skills involving mental processing and psychomotor speed. In women with PD, however, mental rotation accuracy correlated negatively with verbal memory, indicating that higher mental rotation performance was associated with lower ability in verbal memory. These results indicate that PD is associated with visual-spatial orientation deficits in men. Women with PD and control women both performed poorly on the MRT, possibly reflecting a floor effect. Although men and women with PD appear to engage different cognitive processes in this task, the reason for the sex difference remains to be elucidated.

Aged↗
PubMed2003

Age-dependent recall bias for material of internal versus external origin.

OBJECTIVE: To learn whether young and aged subjects exhibit different recall biases for internally derived (Internal) versus externally supplied (External) material. BACKGROUND: Internally derived knowledge, prized by educators and therapists, can bring about dramatic behavioral change. Such information, seldom assessed on formal memory testing, may be preferentially recalled compared with external-origin material. Under some circumstances, however, subjects may demonstrate a recall advantage for externally supplied over internally generated material. METHOD: We compared Internal and External word recall in young and aged subjects with and without explicit intent to remember. RESULTS: Although overall the young and aged subjects recalled the same number of words, we did find a word-origin recall bias. This recall bias differed by age group (P = 0.005). When not instructed to remember words, the young subjects tended to remember more External words, while aged subjects remembered more Internal words. CONCLUSIONS: The differences in the brain mechanisms mediating Internal versus External recall bias are unknown. However, aging may modify an Internal-External memory bias.

Adult↗
PubMed2002

Far bias on the radial line bisection task: measuring perceptual-attentional and motor-intentional bias in normal subjects.

Normal subjects usually err distally when bisecting radial lines below eye level in midsagittal space (far bias). To learn if a radial line bisection bias may be characterized as primarily perceptual-attentional or primarily motor-intentional, we had subjects bisect lines while watching their hand and the line under two video monitoring conditions. In the DIRECT condition, proximal (near) and distal (far) on the video monitor corresponded with the workspace where subjects bisected lines. In the INDIRECT condition, we reversed proximal and distal as they appeared on the monitor. Thus, in the indirect condition, distal hand movement appeared proximal, and vice versa. In the DIRECT condition, subjects erred toward far space (mean 2.075 mm). In the INDIRECT condition, however, subjects erred proximally (mean 1.59 mm, near bias). Distal-proximal reversal of errors over the group of subjects is consistent with a primarily perceptual-attentional bias. In lower body space, normal visual-perceptual-attentional systems may be more biased toward far space than are kinesthetic-motor systems.

Adolescent↗
PubMed2002

Spatial bias: effects of early reading direction on Korean subjects.

Spatial bias may occur in subjects performing a number of cognitive and visual-motor tasks. These include coordinate visuospatial computations (e.g. bisecting a line) and categorical representations of syntactic information (e.g. drawing a picture depicting the action of a sentence). Readers of European languages scan from left-to-right and this learned visual scanning may contribute to leftward spatial bias. In 30 subjects who first learned to read in a top-to-bottom, right-to-left direction (right-left vertical readers, RL), we tested spatial-syntactic bias by reading sentences to subjects, who drew pictures depicting the actions. We noted whether the subject of the sentence was located leftward or rightward of the object. We assessed visual-spatial bias by measuring subjects' accuracy at bisecting lines, and by measuring how closely their drawings on the house-tree-person test were centered on the page. On the spatial-syntactic task, the RL were not right- or left-biased (P=0.581). Korean controls (left-right horizontal readers, LR) also showed no significant spatial-syntactic bias. RL only tended to bisect lines leftward, but displaced house-tree-person drawings left of page center (P<0.001). LR erred leftward on line bisection, and had a smaller magnitude leftward bias on drawing tasks. We conclude that a leftward spatial-syntactic bias may not be innate and does not appear to be influenced by learned reading direction. In contrast, the leftward visual-spatial bias may occur in subjects whose cultural and reading background is neither western nor left-to-right.

Adult↗
PubMed2002

Emotional experience and perception in the absence of facial feedback.

The facial feedback hypothesis suggests that facial expressions are either necessary or sufficient to produce emotional experience. Researchers have noted that the ideal test of the necessity aspect of this hypothesis would be an evaluation of emotional experience in a patient suffering from a bilateral facial paralysis; however, this condition is rare and no such report has been documented. We examined the role of facial expressions in the determination of emotion by studying a patient (F.P.) suffering from a bilateral facial paralysis. Despite her inability to convey emotions through facial expressions, F.P. reported normal emotional experience. When F.P. viewed emotionally evocative slides her reactions were not dampened relative to the normative sample. F.P. retained her ability to detect, discriminate, and image emotional expressions. These findings are not consistent with theories stating that feedback from an active face is necessary to experience emotion, or to process emotional facial expressions.

Adult↗
PubMedDate not supplied

Internally generated memory testing: results of repeated test administration.

A critical memory skill rarely clinically tested is the ability to remember self-generated material. Healthy aged participants (n = 30; Experiment 1) and pilot participants with probable Alzheimer disease (pAD) (n = 9; Experiment 2) were twice administered a memory test including both internally generated and externally supplied items for recall. Healthy aged participants were biased to recall internally originating over externally supplied material on first, but not second, presentation. However, pAD participants demonstrated internal bias during both sessions. The pAD participants were also specifically impaired when told to remember internal material. This study provides further evidence that internally originating items can be used to assess memory. In pAD, memory for internal material with specific attempt to remember may be selectively impaired.

Aged↗
PubMedDate not supplied

Monocular patching in subjects with right-hemisphere stroke affects perceptual-attentional bias.

Monocular patching is a possible inexpensive treatment for spatial neglect. Previous studies were unpromising, but since neglect symptoms are heterogeneous, fractionating spatial bias may detect significant effects of patching. Poststroke, perceptual-attentional (PA) spatial bias, motor-intentional (MI) spatial bias, or both may occur. In this study, six poststroke subjects bisected lines while self-monitoring their performance via a camera/video apparatus. We dissociated PA and MI spatial bias by right-left reversing visual feedback in some trials. Subjects were tested with and without right and left eye patches. Patching did not affect group line-bisection error, but both right and left patches decreased individual subject PA spatial bias (p < 0.05). We detected no patching effect on individual subject MI spatial bias (significant patch side by bias interaction, p = 0.03). When we examined each subject's results separately, patching improved performance in subjects who had greater PA and MI spatial biases. We conclude that monocular patching may primarily affect poststroke PA spatial bias. Further studies on this intervention are needed.

Aged↗