Monocular patching affects inattention but not perseveration in spatial neglect.

Monocular patching might improve perceptual-attentional, not motor-intentional deficits in a patient with chronic post-stroke left spatial neglect. Performing a line-cancellation task, his omission errors were associated with a perceptual-attentional 'where' deficit, while perseverative errors were associated with 'aiming' motor-intentional bias. Contralesional patching had no effect on the omissions (p = .871), whereas ipsilesional patching reduced left-sided omissions compared with the unpatched condition (p = .016). Neither patching condition altered perseverative errors. Further research is needed to examine whether targeting treatments to spatial neglect symptoms (omissions, perseveration) results in improved outcomes.

Incremental limb hypometria.

To find out if patients with right hemisphere strokes (RHD) demonstrate a form of progressive or incremental limb hypometria (ILH), 11 RHD patients and eight matched controls were tested by having them draw a series of horizontal lines while blindfolded. Unlike controls, six RHD patients displayed an incremental decrease in the length of lines they drew, a sign of ILH. ILH might be a common source of disability and hinder rehabilitation efforts.

Auricular microelectrostimulation: naloxone-reversible attenuation of opiate abstinence syndrome.

This study evaluated the effects in rats of very low amplitude (10 mu amp) charge-balanced 10-Hz stimulation delivered bilaterally to low impedance points on the outer ear. This microelectrostimulation markedly and significantly reduced the number of opiate abstinence signs observed following a week of continuous morphine infusion. This effect was prevented by subcutaneous injection of 3 mg/kg naloxone, suggesting that stimulation of endogenous opioid activity plays a major role in the actions of auricular microelectrostimulation.

Testing memory for self-generated items in dementia: method makes a difference.

OBJECTIVE: To learn how pAD (probable Alzheimer's disease), PD+ ("Parkinson's Plus" syndrome), and control subjects remember internally generated material under different conditions. BACKGROUND: "Self-discovered," or internally generated knowledge, prized by educators and therapists, can bring about considerable behavioral change. Both parietal-temporal-limbic (pAD) and frontal-subcortical dementia (e.g. PD+) cause dysmemory, but may cause different internal-external memory bias. pAD subjects, confusing internal and external information (confabulation) and reporting internal information during memory testing (intrusions), may be biased to remember internal material. PD+ subjects, impaired at generative tests, may be externally biased. METHODS: Ten pAD, 5 PD+, and 10 control subjects generated words in a category without instruction to remember (INR), and took a list-learning test of incidental memory for internally and externally generated words. To test how INR influences memory, subjects then generated and attempted to recall four more words. RESULTS: All three subject groups remembered more internally generated than externally provided words without INR. Recall versus recognition of internally generated words differed by group, with PD+ subjects showing greatest improvement with recognition. The pAD subjects performed worse with INR than without INR, had the most intrusion errors, and, rather than demonstrating a release from proactive inhibition, recalled fewer words outside the category. Groups differed in overall recall/recognition improvement (p = 0.015). CONCLUSIONS: Aged subjects preferentially retained internally generated material. However, among demented subjects, memory for internally generated words was influenced by the testing method used. PD+ subjects have poor internal recall, but excellent internal recognition. In pAD, memory for internally generated words may exceed external memory, but only when subjects are not explicitly trying to remember.

Extinction, working memory, and line bisection in spatial neglect.

The authors studied four patients with spatial neglect, using a task in which lines contain an off-centered bisection mark and a task in which the right and left segments of these bisected lines are presented independently and sequentially. In the prebisected line task, subjects reported the position of the bisection. In the segments task, subjects compared the length of the segments. Accuracy was greater with the sequential presentation of line segments, suggesting that an extinction-like phenomenon plays a role in line bisection bias.

Neglect after right hemisphere stroke: a smaller floodlight for distributed attention.

OBJECTIVE: To learn whether there was a defect in an attentional floodlight. We used a line decision task for which subjects had to decide if two line segments separated by a gap were one line or two parallel lines. We varied the area of the gap and, therefore, the area over which subjects needed to spread attention to perform the task correctly. BACKGROUND: Visual tasks requiring focused attention use an attentional spotlight. Other visual tasks requiring spatially distributed attention may require a floodlight. Neglect after right hemisphere stroke can be associated with a defect in the attentional spotlight. RESULTS AND CONCLUSIONS: Two patients with neglect after right hemisphere stroke performed more poorly than normal control subjects and left hemisphere-damaged control subjects as the area of spread in the gap increased. Right hemisphere-damaged patients did not differ from control subjects' performance on another visuospatial parameter--the degree of discontinuity between the line segments. These results support a defective attentional floodlight in neglect.

Seeing trees but not the forest: limited perception of large configurations in PD.

OBJECTIVE: To learn if Parkinson's disease (PD) is associated with a restricted attentional "floodlight." BACKGROUND: Different visual tasks may have different attentional requirements. Focused attention may be needed for some tasks; other tasks demand spatially distributed attention. Neglect after right cortical injury and dopamine depletion may limit the area over which attention can be spread. Although subjects with PD have dopamine depletion and can perform poorly on tests of visuospatial function, it is unclear if their attentional floodlight is restricted. METHODS: Eleven subjects with PD and 11 control subjects viewed different-sized letters on five printed stimulus sheets, 43 x 56 cm. On each sheet, four different large letters (14 cm2) were composed of four different medium-sized letters (2.5 cm2), which in turn were composed of four different small letters (0.4 cm2). Stimulus sheets were presented at 30- and 75-cm viewing distances. Subjects named "all the letters they could see." RESULTS: Subjects with PD named small- and medium-sized letters comparably to control subjects, but PD subjects named fewer large letters than control subjects (control = 65.68%, PD = 24.55%; group-by-letter-size interaction, p < 0.05). Subjects with PD who had undergone stereotactic pallidotomy named more letters than prepallidotomy PD subjects (p = 0.05). CONCLUSIONS: PD may affect the patient's ability to perceive large spatial configurations. As global configurations in subjects may be perceived preferentially over local patterns, it is possible that DA depletion induces an aberrant perceptual-attentional bias, such that patients have a narrowed attentional floodlight.

Emotional conversations in Parkinson's disease.

OBJECTIVE: To learn how PD influences verbal description of emotional events. BACKGROUND: Individuals with PD exhibit emotional processing deficits. Emotional experience likely involves several dimensions (e.g., valence, arousal, motor activation) subserved by a distributed modular network involving cortical, limbic, basal ganglia, diencephalic, and mesencephalic regions. Although the neurodegeneration in PD likely affects components in this network, little is known about how PD influences emotional processing. Because PD is associated with activation deficits, one could predict that the discourse of emotional experiences involving high activation would be reduced in patients with PD compared to control subjects. Alternatively, because patients with PD exhibit paradoxical sensitivity to externally evoked motor activation (kinesia paradoxica), it is possible that emotional stimuli may facilitate verbal emotional expression more so in patients with PD than in control subjects. METHODS: The authors measured verbal descriptions of personal emotional experiences in subjects with PD and normal controls. RESULTS: Compared with control subjects, individuals with PD showed a relative increase in the number of words spoken and in discourse duration when talking about emotional experiences that are usually associated with high levels of arousal and motor activation. Although the authors did not measure arousal or activation, prior research has shown that, when asked to recall an emotional experience, people will often re-experience the emotion previously experienced during that episode. CONCLUSIONS: Recalling emotional episodes induces verbal kinesia paradoxica in patients with PD. Although recall of these emotional episodes may have been associated with increased arousal and activation, the mechanism underlying emotional verbal kinesia paradoxica is unclear.

Attentional grasp in far extrapersonal space after thalamic infarction.

Studies of animals and humans with focal brain damage suggest that attention in near and far extrapersonal space may be mediated by anatomically separate systems. Thalamic lesions have been associated with spatial neglect, but whether asymmetric attention specific to near or far space occur after thalamic damage has not been explored. It is also unclear if thalamic injury can induce contralesional defective response inhibition. We tested a woman with a left thalamic infarction who reported that, when driving, she had a tendency to veer towards people or objects on the right side of the road. Our patient and four controls performed a line bisection task with a laser pointer in near and far extrapersonal space. The experimenter marked each bisection either from the right of the presented line (right-distractor, RD) or the left (left-distractor, LD). RD and LD trials were pseudo-randomized. Our patient performed similarly to controls (mean -0.7 mm, controls -0.6 mm) on the line bisection task in near space. In far space she erred significantly rightward compared to her performance in near space (p<0.001). Controls performed similarly in near and far space. The experimenter position did not affect our patient's performance on near line bisections, nor did controls demonstrate a distractor effect for the near condition. In the far condition, however, our patient showed a significant distractor effect (LD -3.3 mm, RD 35.3 mm, p<0.001). Controls also demonstrated a distractor effect in the far condition (LD -6.4 mm, RD 0.7 mm, p<0.01), though of much smaller magnitude. Our results suggest that frontal-thalamic systems regulating visual attention may be disrupted by thalamic infarction. Such damage may produce an attentional grasp specific to far extrapersonal space.

Cognitive and vestibulo-proprioceptive components of spatial ability in Parkinson's disease.

Visual-spatial deficits are often associated with Parkinson's Disease (PD). Recent theories suggest that frontal-basal ganglionic dysfunction affects cognition in PD. Although this hypothesis does not entirely explain spatial deficits in PD, the inappropriate utilization of cues associated with executive dysfunction may induce spatial deficits. Alternatively, the vestibular system is also involved in spatial cognition, and vestibular dysfunction may affect visual-spatial ability in PD. To test these hypotheses, we administered the Water Jar Test, while perturbing vestibulo-proprioceptive input. Non-demented PD patients were significantly less accurate than controls in judging horizontal, and appeared to inappropriately utilize cues. No group effect was found for head tilt. These findings suggest the visual-spatial difficulties seen in PD are related to executive dysfunction that is associated with a disruption of the frontal-basal ganglionic and frontal-parietal systems.

Emotional and physiological responses to false feedback.

The relationship between autonomic-visceral arousal and emotional experience is unclear. The attribution or cognitive-arousal theory of emotional experience posits that emotional experience is dependent on both visceral-autonomic nervous system feedback and the cognitive interpretation of the stimulus that induced this visceral activation. The finding that false cardiac feedback can alter emotional experience suggests that it may be the conscious perception that one is aroused, together with the cognitive interpretation of the stimulus that are important in developing emotional experience. Because the right hemisphere appears to play a special role in modulating arousal and interpreting emotional stimuli, it is possible that right hemisphere damage may interfere with developing the computations needed for emotional experience. To test this hypothesis we exposed men, both neurologically intact and those with right and left hemisphere lesions, to emotionally provocative pictures that were paired with false cardiac feedback, and examined the effects of this false feedback on their ratings of attractiveness of these pictures and their cardiac reactivity to this information. Subjects with left hemisphere damage, but not right hemisphere damage, showed significant changes in their emotional rating whereas control subjects showed marginal reactivity in their emotional ratings. Subjects with left hemisphere damage also showed significant changes in their cardiac reactivity. This finding is consistent with prior reports that indicate, when compared to right hemisphere damaged patients and normal controls, patients with left hemisphere lesions have an increased visceral-autonomic response to stimuli. These findings further provide support for the postulate that it is the cognitive interpretation of perceived physiological arousal together with the cognitive interpretation of the stimulus that is important in the development of emotional judgment and experience. These results do not support the approach-left hemisphere/avoidance-right hemisphere dichotomy, but instead suggest that left hemisphere damage increases reactivity to false feedback, and that the intact right hemisphere function integrates the cognitive interpretation of the emotional information and perceived arousal that lead to that emotional judgment. That these subjects showed no consistent relationship between their measures of cardiac reactivity and their ratings of attractiveness detracts from the James-Lange and attribution theories. These subjects also showed no consistent relationship between their knowledge of affective physiological reactivity and their ratings of attractiveness, or between their knowledge of physiological reactivity and actual measures of cardiac reactivity, suggesting that other neuropsychological factors are involved in making an emotional judgment.

The MoCA: well-suited screen for cognitive impairment in Parkinson disease.

OBJECTIVE: To establish the diagnostic accuracy of the Montreal Cognitive Assessment (MoCA) when screening externally validated cognition in Parkinson disease (PD), by comparison with a PD-focused test (Scales for Outcomes in Parkinson disease-Cognition [SCOPA-COG]) and the standardized Mini-Mental State Examination (S-MMSE) as benchmarks. METHODS: A convenience sample of 114 patients with idiopathic PD and 47 healthy controls was examined in a movement disorders center. The 21 patients with dementia (PD-D) were diagnosed using Movement Disorders Society criteria, externally validated by detailed independent functional and neuropsychological tests. The 21 patients with mild cognitive impairment (PD-MCI) scored 1.5 SD or more below normative data in at least 2 measures in 1 of 4 cognitive domains. Other patients had normal cognition (PD-N). RESULTS: Primary outcomes using receiver operating characteristic (ROC) curve analyses showed that all 3 mental status tests produced excellent discrimination of PD-D from patients without dementia (area under the curve [AUC], 87%-91%) and PD-MCI from PD-N patients (AUC, 78%-90%), but the MoCA was generally better suited across both assessments. The optimal MoCA screening cutoffs were <21/30 for PD-D (sensitivity 81%; specificity 95%; negative predictive value [NPV] 92%) and <26/30 for PD-MCI (sensitivity 90%; specificity 75%; NPV 95%). Further support that the MoCA is at least equivalent to the SCOPA-COG, and superior to the S-MMSE, came from the simultaneous classification of the 3 PD patient groups (volumes under a 3-dimensional ROC surface, chance = 17%: MoCA 79%, confidence interval [CI] 70%-89%; SCOPA-COG 74%, CI 62%-86%; MMSE-Sevens item 56%, CI 44%-68%; MMSE-World item 62%, CI 50%-73%). CONCLUSIONS: The MoCA is a suitably accurate, brief test when screening all levels of cognition in PD.

Cognitive decline tracks motor progression and not disease duration in Parkinson patients.

We performed an analysis of prospectively-acquired cross sectional data on 106 Parkinson disease (PD) patients who underwent comprehensive neuropsychological testing and the Unified Parkinson Disease Rating Scale (UPDRS) motor scale. A significant correlation between the UPDRS motor and neuropsychological tests in all cognitive domains except for general intelligence and visuo-spatial function was seen. In this study, cognitive decline within this PD cohort correlated with motor impairment but not disease duration. Our findings suggest that overall cognitive impairment (except visuospatial dysfunction) may track motor progression in PD more than duration of disease. Longitudinal studies are needed to confirm our results.

What's inside the art? The influence of frontotemporal dementia in art production.

We evaluated the productions of an artist with frontotemporal lobar degeneration from before dementia onset until she was fully symptomatic. We noted an improvement of technique that might be related to sparing and disinhibition of the right posterior neocortex. There was a reduction of closure (completeness of the painting), possibly induced by impersistence and a decrease in evocative impact that might be explained by frontal and anterotemporal-limbic dysfunction.

Sex differences in right hemisphere tasks.

We tested the hypothesis that sex differences in spatial ability and emotional perception are due to sex differences in intrahemispheric organization of the right hemisphere. If the right hemisphere is differently organized by sex-primarily specialized for spatial ability in men, but primarily specialized for emotional perception in women-then there should be a negative correlation between spatial ability and emotional perception within sex, and the greatest disparity between abilities should be found in people with characteristic arousal of the right hemisphere. Undergraduate men (N = 86) and women (N = 132) completed tests of Mental Rotation, Surface Development, Profile of Nonverbal Sensitivity, Progressive Matrices, and Chimeric Faces. Although the expected pattern of sex differences was observed, there was no evidence for the hypothesized negative correlation between spatial ability and emotional perception, even after statistical control of general intelligence.

Adverse effect of dopamine agonist therapy in a patient with motor-intentional neglect.

Studies in animals and humans report dopamine agonists can improve neglect. Because dopamine deficit reduces intention to act, it has been suspected the dopamine agonist bromocriptine would improve deficient hemispatial intention. Thus, the effect of bromocriptine on line bisection was examined in a patient with neglect and failure of the action-intention system. The 58-year-old patient had left-sided neglect from a right cerebral infarction involving both cortical and subcortical (striatal) structures. It was determined that neglect on a line bisection task was attributable to a motor-intentional bias by testing under congruous and incongruous video monitoring. Testing sessions were held before starting bromocriptine, on 20 mg/d, and after stopping bromocriptine. The patient's ipsilesional bias increased on bromocriptine, and improved when bromocriptine was stopped. Bromocriptine may worsen neglect if putamenal receptors are damaged. Dopamine agonists may activate the normal hemisphere, increasing an intentional bias. Clinicians using dopaminergic pharmacotherapy should assess patients for this possible adverse effect.

Spared comprehension of emotional prosody in a patient with global aphasia.

BACKGROUND: Several studies have demonstrated that patients with right hemisphere damage, when compared with left-hemisphere damaged controls, are impaired at comprehending emotional prosody. Critics of these studies, however, note that selection may have been biased because left-hemisphere-damaged subjects had good verbal comprehension. OBJECTIVE: To learn whether a subject with a large left hemisphere stroke and global aphasia could comprehend emotional prosody in spoken material. METHOD: The authors formally tested speech and language with the Western Aphasia Battery and comprehension of emotional prosody and emotional facial expression with the Florida Affect Battery. RESULTS: The patient could not perform verbally mediated tests but demonstrated spared ability to match emotional prosody to emotional facial expressions under a variety of conditions. CONCLUSIONS: These observations further support the idea that verbal and emotional communication systems are independent and mediated by different hemispheres.

Monocular patching may worsen sensory-attentional neglect: a case report.

To determine whether monocular patching influences the performance of a patient with primarily sensory-attentional bias on the line bisection task, we present a case study of a 49-year-old woman who had right cortical infarction affecting temporal, parietal, and occipital regions. She had primarily sensory-attentional bias when performing the line bisection task on a video apparatus. In hospital, she was tested with monocular eye patching of the left or the right eye or unpatched. Paradoxically, the right-eye patching significantly worsened and the left patch significantly improved performance. The eye may have some input to the ipsilateral as well as the contralateral superior colliculus. Alternatively, the patch-a novel tactile stimulus-may induce orienting to its side via noncollicular mechanisms. When using a monocular patch for any reason, clinicians should be aware that increased spatial bias may occur.

The Gerstmann syndrome in Alzheimer's disease.

BACKGROUND: It remains unclear from lesion studies whether the four signs of the Gerstmann syndrome (finger agnosia, acalculia, agraphia, and right-left confusion) cluster because the neuronal nets that mediate these activities have anatomical proximity, or because these four functions share a common network. If there is a common network, with degeneration, as may occur in Alzheimer's disease, each of the signs associated with Gerstmann's syndrome should correlate with the other three signs more closely than they correlate with other cognitive deficits. METHODS: Thirty eight patients with probable Alzheimer's disease were included in a retrospective analysis of neuropsychological functions. RESULTS: The four Gerstmann's syndrome signs did not cluster together. Finger naming and calculations were not significantly correlated. Right-left knowledge and calculations also did not correlate. CONCLUSIONS: The four cognitive functions impaired in Gerstmann's syndrome do not share a common neuronal network, and their co-occurrence with dominant parietal lobe injuries may be related to the anatomical proximity of the different networks mediating these functions.