A diagnostic test of unawareness of bilateral motor task abilities in anosognosia for hemiplegia.

Anosognosia for hemiplegia (AHP) is conventionally defined/diagnosed by generic questions about awareness of limb plegia. However, unawareness of inability to perform tasks requiring bilateral use of limbs is more widespread and outlasts generic unawareness of plegia. Some patients consistently overestimate bilateral task ability. Our aim was to assess how well specific questions about bilateral task ability predict whether patients consistently overestimate their abilities. Six statistical indices were calculated to rank the questions for predictiveness of consistency of overestimation of bilateral task ability. Overall, bimanual questions are better predictors than bipedal questions of consistent overestimation. Three bimanual and two bipedal questions had both sensitivity and specificity above 80%. On the basis of accuracy and discriminability, one bimanual and one bipedal question that performed maximally could be used for a quick bedside heuristic index. For a more thorough diagnostic, especially for research, five bimanual and two bipedal questions were good predictors, and should be used. For both purposes, such tests should be given in combination with conventional generic questions assessing awareness of limb plegia, since the two kinds of question reflect different kinds of unawareness of motor incapacity.

Training to improve awareness of disabilities in clients with unilateral neglect.

OBJECTIVE: Awareness of disabilities is known to be a central problem of rehabilitation among clients with large right cerebrovascular lesions and unilateral neglect. The aim of this study was to evaluate the effect of an intervention program focused on improving the awareness of disabilities in four participants with unilateral neglect. The intervention program developed for this study was based on the assumption that awareness of disabilities is a prerequisite for being able to learn and use compensatory techniques in the performance of activities of daily living (ADL). METHOD: The study followed a single-case experimental ABA design. The Assessment of Awareness of Disability was used to measure awareness of disabilities; the Assessment of Motor and Process Skills was used to measure ADL ability; and neuropsychological tests were used to assess unilateral neglect and sustained attention. The intervention program used meaningful and purposeful occupations as therapeutic change agents to improve awareness of disabilities. RESULTS: Awareness of disabilities and ADL ability improved in all four participants; unilateral neglect decreased in three participants; and sustained attention improved in two participants. CONCLUSION: The preliminary findings indicate that training to improve awareness of disabilities might improve the ability to learn the use of compensatory techniques in the performance of ADL in clients with unilateral neglect. The effects of the intervention strategy need to be evaluated further in future research.

Line bisection with a head-mounted pointing device: an investigation of the role of right hand use and bilateral hemisphere activation in left neglect.

Left hand use in left hemispace has been shown to reduce left neglect. Right hand use can theoretically increase neglect by right spatial cueing and left hemisphere activation. The aim of the present study was to investigate the role of right hand use and right hemisphere activation in left neglect by dissociating hemisphere activation from the hemispace in which the motor response is made. Twelve neglect patients performed line bisection by two means: with their right hand and with a lamp mounted centrally on the forehead ('miner's lamp'). Lamp use induces left and right hemisphere activation without hemispace involvement. Bisection with the lamp and the hand were done with right, left and neutral cues. No difference was found in bisection performance between lamp and right hand use, and no interaction between lamp/hand use and cueing. This indicates that right hand use per se does not influence neglect in line bisection. It is suggested that the apparent lack of right hemisphere activation with lamp use is due to the widespread right-sided lesion of the typical neglect patient.

Video feedback in the rehabilitation of patients with unilateral neglect.

OBJECTIVE: To compare the effects of a video procedure and a conventional verbal procedure in giving patients feedback on their neglect behavior in a practical task. DESIGN: Subjects in group A were trained with a video feedback procedure and subjects in group B with a conventional, verbal procedure. Three hours after the procedures, the subjects were tested with four different neglect tests to evaluate the effects of training. SUBJECTS: A consecutive series of 14 right-brain-damaged patients with moderate to severe unilateral neglect (UN): 7 patients in group A and 7 in group B. INTERVENTIONS: Subjects in group A were given the opportunity to see their performances on video, directly after the performance of the "Baking Tray Task" (BTT). They could see their neglected left side on the right side of the TV monitor. Subjects in group B were given verbal and visual guidance to see their results in the BTT. MAIN OUTCOME MEASURES: Line Cancellation Task, Figure Copying Task, Line Bisection, and BTT before and after procedures. RESULTS: The video feedback group improved significantly in the BTT, as tested 3 hours after training (p < .02). Conventional training had no effect on the BTT or on the other neglect measures. In the video feedback group, no generalization effects from the videotaped BTT on other neglect tests were observed. CONCLUSION: Video feedback seems to be a useful technique in the rehabilitation of patients with unilateral neglect.

Sustained attention and awareness of disability in chronic neglect.

The possible causative role of defective sustained attention and awareness of disability on the persistence of neglect was explored. The study included stroke patients who had had moderate or severe neglect 1-5 years before the start of the present examination. Questionnaire responses showed that the patients were aware of their disability. Impaired sustained attention was associated with poor performance in two out of three tests most sensitive in detecting neglect. This, together with indications of compensation on neglect tests, is interpreted as providing support for the hypothesis that chronic neglect is related to an impaired sustained attention.

Dissociation of ophthalmokinetic and melokinetic attention in unilateral neglect.

A line cancellation task was performed by 36 right brain-damaged patients with unilateral neglect under four different conditions: normal and mirror-reversed view, with and without cueing. Two types of unilateral neglect were distinguished by directing ophthalmo- and melokinetic components of visuomanual scanning to opposite sides of the stimulus array. In ophthalmokinetic neglect, contralesional visual scanning of the stimulus array was defective, while manual scanning was unimpaired. The converse was true of melokinetic neglect. Ophthalmokinetic neglect was predominantly associated with posterior brain damage, while melokinetic neglect was predominantly associated with frontal or subcortical brain damage. In a few instances, cueing visuomanual scanning toward the neglected side of the stimulus array converted ophthalmokinetic into melokinetic neglect, and vice versa. The results are held to be indicative of two components of space representation and to provide further evidence of response-driven modulation of perceptual awareness.

Sustained attention training for unilateral neglect: theoretical and rehabilitation implications.

Many studies have shown a co-variation of unilateral neglect with nonlateralised attentional functions. Recently, Posner has argued that there are two separate neural systems that influence the posterior attentional system which is presumed to be impaired in unilateral neglect, namely, the posterior system itself (located partly in the inferior parietal lobules) as well as a secondary modulatory sustained attention or vigilance system. This latter system is linked to the nor-epinephrine system, which is known to be more strongly represented in the right compared to the left hemisphere of the brain. If this hypothesis is true, then unilateral neglect should be improved by increasing activation of the sustained attention system. Eight patients suffering from chronic left unilateral neglect were trained to sustain their attention by a self-alerting procedure partially derived from Meichenbaum's self-instructional methods. Using a multiple-baseline-by-function design, as well as multiple-baseline-by-subject designs, statistically significant improvements in unilateral neglect as well in sustained attention were found following onset of sustained attention training, without corresponding improvements in control measures. Theoretical implications for the attentional underpinnings of unilateral neglect are discussed, as well as the rehabilitation implications of this training procedure.

Walking trajectory and hand movements in unilateral left neglect: a vestibular hypothesis.

This is the first systematic study of walking trajectories in unilateral neglect. Six patients with unilateral left neglect approached and walked through a doorway, and all six deviated to the right of centre when doing so. Four out of six significantly centred their walking trajectories by making left hand movements while approaching the doorway. The group effect of walking with no hand movements vs walking with hand movements was statistically significant. Age-matched control patients showed a similar but significant smaller rightward deviation. The results are interpreted in terms of recent research in limb activation effects on neglect (Robertson and North, Neuropsychologia 30, 553-563, 1992), and also in the light of research showing close anatomical correspondence between the cortical projections of the vestibular nerve on the one hand, and the hand/arm representational fields of the central sulcus on the other.

Visual and tactile rod bisection in unilateral neglect.

A rod bisection task was performed by 16 RBD patients with visual neglect, 10 RBD and 10 LBD patients without visual neglect, and 10 normal controls. Three different conditions were used: tactile, where they explored the rod blindfolded; visuo-tactile, where they explored the rod manually without blindfold; and visual, where they pointed to the midpoint without prior manual exploration. Only within the RBD group with visual neglect was there a significant difference between the three conditions. These patients made large rightward errors under the visual condition but no significant deviations from actual midpoint under the visuo-tactile or the tactile condition. It is therefore possible that rod exploration, which is an integral part of tactile bisection, reduces neglect to such an extent that it is difficult to identify neglect in the tactile modality on this task.

Word length coding in neglect dyslexia.

Single word reading was examined in two patients with left visual neglect. Both patients showed preservation of word length, which is the salient feature of neglect dyslexia. By varying lexical and contextual parameters we could, however, induce responses considerably shorter or longer than the stimuli. The findings are relevant to current accounts of neglect dyslexia.

Tactile line-bisection in normal subjects.

The effects of spatial position, handedness, and hand of performance were assessed in 36 normal subjects using a tactile line-bisection task described in 1980 by Bowers and Heilman. An interaction between hand of performance and spatial position indicated that both hemispace and anatomical pathways determine laterality effects. Neither the left-hand superiority nor the leftward error in the midline condition by both hands found in an earlier study could be observed here. Only right-handers were influenced by starting condition, which in this setting acted as a spatial cue. Finally, some subjects used nonspatial strategies, a confounding factor that needs evaluation in further studies.

Darkness improves line bisection in unilateral spatial neglect.

This study was performed to determine the influence of background illumination on the performance of patients with left visual neglect. We examined six RBD patients with unilateral visual neglect, and as controls six RBD patients and six LBD patients without neglect. A luminous line consisting of LEDs was used in a line bisection task under two conditions, normal illumination and darkness. As expected, neglect patients made large rightward errors under normal illumination. Their performance improved by about 43% in darkness. Our results are discussed with reference to earlier studies of space exploration without visual guidance.

A tactile maze test in unilateral spatial neglect: the influence of vision and recording technique.

Right brain-damaged patients with left spatial neglect were examined on a tactile maze task. They started to explore the right side of the maze and their search times were longer on the left side. Their performance was the same whether blindfolded or not, which contrasts with the results of other studies and probably reflects differences in task demand. The present results do not support a previous observation that visual neglect can be compensated through the tactile modality. Our patients had markedly longer search times than normal controls in the right as well as the left hemifield, and search times in both hemifields were positively correlated. The outcome of the maze test in this context may therefore depend to a large extent on impaired topographical processing.

The influence of stimulus properties on visual neglect.

Twenty five patients with right cerebral hemisphere damage and neglect participated in a series of bisection experiments. As expected, long lines were bisected to the right of true midpoint. By contrast, large circles and long white paper strips were bisected accurately, or with leftward errors. Small objects were less sensitive to stimulus properties: short lines and paper strips, and small circles, were bisected to the left of true midpoint, and these leftward errors were equally common as rightward errors with long lines. When asked to draw a perpendicular line of the same length as the presented horizontal line, patients overestimated the length of short lines but underestimated that of long lines. Presenting lines in near and far extrapersonal space selectively affected bisection of short lines. The results suggest that two opposing, independent mechanisms determine bisection performance in left neglect.

Through a looking glass. A new technique to demonstrate directional hypokinesia in unilateral neglect.

A line cancellation task was performed by right brain-damaged patients with neglect in two response conditions. The task was presented either in normal view or through a 90 degree angle mirror with direct view prevented. The latter decouples the direction of visual attention and of arm movement. In the mirror condition, 4 of 18 patients cancelled lines only in right hemispace which means that they directed their visual attention to the left but failed to execute movements towards contralateral hemispace--what has been termed directional hypokinesia. In contrast, 10 patients cancelled lines only in left hemispace in the mirror condition, which accords better with attention-representation deficit hypotheses. Our results support a division of the neglect syndrome according to whether perceptual or premotor deficits are predominant.

Apparent right neglect in patients with left visual neglect.

Two patients with unilateral left visual neglect were asked to bisect lines of different lengths. They showed, as expected, a rightward bias with longer lines. In contrast, they consistently transected very short lines (25 mm) to the left of the objective midpoint. The finding confirms a previous observation of similar behaviour but differs in other aspects that are of theoretical importance.

"To hundred and twenty4our": a study of transcoding in dementia.

The ability to transcode integers from ideographic to alphabetic script was assessed in patients with dementia of Alzheimer type. Eleven of 13 consecutive patients made characteristic errors of intrusion. We propose that this may be a simple bedside test for dementia.

Correspondence between neurological symptoms and outcome of quantitative sensory testing in the hand-arm vibration syndrome.

To evaluate neurological symptoms in the vibration syndrome, 55 patients with vascular and neurological symptoms in the hand who had been exposed to vibration were examined. Their exposure to vibration was estimated and neurological vascular symptoms were evaluated according to symptom scales. Temperature thresholds were measured on the right thenar eminence and on the distal volar aspect of the second and third fingers held together on both sides. Vibration thresholds were measured dorsally on the second and fifth metacarpal bones and on the second and fifth fingers proximal to the nail roots. Subjects with advanced neurological symptoms had higher temperature and vibration thresholds than subjects with less advanced symptoms. No such relation was found between vascular symptoms and the outcome of sensory testing. Thus neurological but not vascular symptoms are reflected by the outcome of quantitative sensory testing. In subjects with advanced neurological symptoms the tests gave a high proportion of abnormal results, indicating that these tests may be used for the diagnosis of vibration syndrome on an individual basis. Patients with advanced vascular and neurological symptoms had higher exposure dose scores than patients with less advanced symptoms, indicating a dose response relation between vibration "dose" and neurological and vascular symptoms.