Unawareness of motor impairment and emotions in right hemispheric stroke: a preliminary investigation

BACKGROUND: Awareness may lack in some stroke patients who are not capable of evaluating the nature and severity of illness. Thus, unawareness may have different forms such as anosognosia, neglect, and alexithymia or unawareness of emotions. In this study we investigated the relationship among anosognosia, neglect, alexithymia, and cognition. METHODS: Fifty consecutive right stroke inpatients were approached within the first 3 months from the acute event. Anosognosia was measured with the Bisiach scale, alexithymia with the TAS-20 scale and neglect with line crossing, letter cancellation, figure and shape copying, and line bisection tests. A neuropsychological test battery was used to measure different areas of cognition. RESULTS: despite the strong comorbidity rate among the different forms of unawareness, there are patients who suffer from pure forms of these types of lack of awareness. A multivariate logistic regression model evidenced that presence of neglect (OR = 10.3; 95% CI = 1.4-76.3; p = 0.023) and more difficulty in describing feelings (TAS-20 F2 subscore; OR = 1.3; 95% CI = 1.1-1.7; p = 0.014) were the only predictors of anosognosia. In addition, anosognosics with alexithymia performed worst in a frontal task such as the verbal fluency task (p = 0.042) and in the verbal span forward task (p = 0.026) than pure anosognosics. CONCLUSIONS: Anosognosia for motor impairment is strictly associated with a specific form of unawareness of emotions. Future studies have to clarify if frontal cognitive impairment previously described in anosognosics is a manifestation of unawareness of emotions or anosognosia for motor impairment.     

Predictors of discharge to home during the first year after right hemisphere stroke

OBJECTIVES: The aim of this study was to explore predictive factors of the length of hospital stay at the acute stage of right hemisphere stroke. Special attention was paid to the possible role of anosognosia for hemiparesis and anosognosia for neglect in this prediction. PATIENTS AND METHODS: A consecutive series of 57 patients having their first right hemisphere stroke were examined at the acute phase. Forty-nine patients were included in this study and followed-up for 12 months. The examinations were conducted within 2 weeks of onset. The outcome variable was the time (days) from stroke to discharge to home. The predictors were age, gender, size of infarct, neglect, hemiparesis, verbal memory, unawareness of illness, anosognosia for neglect, anosognosia for hemiparesis and presence of a relative at home. RESULTS: Hemiparesis and unawareness of illness lengthened the duration of the hospital stay, the presence of a relative reduced it. Neglect was the best single predictor of poor outcome, but it had no additional value in the combination of the three predictors above. Neither anosognosia for hemiparesis nor anosognosia for neglect were important predictors. CONCLUSION: Hemiparesis, unawareness of illness and presence of a relative at home were the best predictors of the time from right hemisphere stroke to discharge to home.     

Anosognosia after stroke: assessment, occurrence, subtypes and impact on functional outcome reviewed

PURPOSE: This review provides an update on recent research findings concerning the methods used in the assessment of anosognosia, the occurrence and subtypes of anosognosia, the association between anosognosia and neglect, and the impact of anosognosias on functional outcome. METHODS: A systematic review covering the period from 1995 to 2005 was carried out on reports drawn from electronic databases (MEDLINE, PSYCHLIT) and identified from the references in these reports. Twenty-seven articles met the selection criteria. RESULTS: The results of this review are in line with previous findings in the following respects: anosognosia was more often associated with right hemisphere damage, neglect and anosognosia co-occurred, and anosognosia had predictive value on poor functional outcome. The variation in the methods used in the assessment of anosognosia, patient samples and assessment times influence the occurrence rates and the predictive value of anosognosia, which might undermine the generalizability of the results. CONCLUSIONS: More homogeneous patient samples and consistency in the assessment methods and evaluation times would facilitate comparisons of the occurrence and the impact of anosognosia on functional outcome. New methods need to be developed for the assessment of anosognosia. These new methods should take account of the subtypes of anosognosia both at verbal and at non-verbal levels.     

Denial in the first days of acute stroke

Denial is a disorder of self-awareness that is frequent after acute stroke, with potential negative influence in the care of patients. The aim of this study was to describe the presence and correlates of denial in acute stroke. We assessed denial in a sample of 180 consecutive acute stroke patients (≤4 days) and in a control group of 50 acute coronary patients using the Denial of Illness Scale (DIS). 41% (74) acute stroke patients (mean DIS score=4.1, SD=2.2, range 0 to 10) and 24% (12) acute coronary patients (mean DIS score=3.2, SD=1.5, range 0 to 10) presented denial (χ²=4.19, p=.04; U=3405.50, p=.01). Denial was more frequent and severe in patients with lower educational level (χ² = 5.04, p=.04; U=2110.50; p=.01), neglect (χ² = 21.38, p=.00; U=1130.50; p=.00), cognitive impairment (χ² = 6.27, p=.02; U=1181.50; p=.01) and after hemispherical lesions (χ² =4.68, p=.05; U=1982.50; p=.04). In logistic regression low educational level, neglect and cognitive impairment were independent factors predicting denial in stroke patients (R²= 21%). Patients with denial can express depressive symptoms. Patients with denial had a worse outcome at discharge (χ² =4.91, p=.04; U=2918.00; p=.03). Denial is a frequent phenomenon after acute stroke. We propose that there is a multifactorial model for the emergence of denial, lower educational as a predisposing condition, and acute stroke due to hemisphere lesion and causing neglect and cognitive impairment as precipitating events. All these factors limit patients’ assessment of their condition and body functions.     

Anosognosia versus unilateral neglect. Coexistence and their relations to age, stroke severity, lesion site and cognition

The aim of this study was to examine the association between anosognosia and unilateral neglect (UN), with special focus on age, stroke severity, lesion location and pre-stroke dementia. The basis of this investigation was a population-based stroke incidence study. Anosognosia was assessed using a questionnaire, and UN using a three-item version of the Behaviour Inattention Test, the Baking Tray Task and a test of personal neglect. Stroke severity was assessed using the NIH stroke scale. Patients with anosognosia were older, and they more often had pre-stroke dementia than patients having UN only. No particular lesion localization was associated with anosognosia, while UN was strongly associated with previously defined lesion sites, often in the parietal lobe. There was a borderline significance regarding stroke severity in patients having anosognosia compared with those with UN only. Patients with anosognosia had higher mortality than patients without, but when controlled for age and stroke severity, this effect was not independent. While UN is closely associated with 'classical' lesion sites, anosognosia is a condition that more often occurs in a previously impaired brain. For anosognosia, lesion location appears to be less important. Anosognosia also tends to occur with larger strokes.     

Dynamic brain structural changes after left hemisphere subcortical stroke

This study aimed to quantify dynamic structural changes in the brain after subcortical stroke and identify brain areas that contribute to motor recovery of affected limbs. High‐resolution structural MRI and neurological examinations were conducted at five consecutive time points during the year following stroke in 10 patients with left hemisphere subcortical infarctions involving motor pathways. Gray matter volume (GMV) was calculated using an optimized voxel‐based morphometry technique, and dynamic changes in GMV were evaluated using a mixed‐effects model. After stroke, GMV was decreased bilaterally in brain areas that directly or indirectly connected with lesions, which suggests the presence of regional damage in these “healthy” brain tissues in stroke patients. Moreover, the GMVs of these brain areas were not correlated with the Motricity Index (MI) scores when controlling for time intervals after stroke, which indicates that these structural changes may reflect an independent process (such as axonal degeneration) but cannot affect the improvement of motor function. In contrast, the GMV was increased in several brain areas associated with motor and cognitive functions after stroke. When controlling for time intervals after stroke, only the GMVs in the cognitive‐related brain areas (hippocampus and precuneus) were positively correlated with MI scores, which suggests that the structural reorganization in cognitive‐related brain areas may facilitate the recovery of motor function. However, considering the small sample size of this study, further studies are needed to clarify the exact relationships between structural changes and recovery of motor function in stroke patients. Hum Brain Mapp, 2013. © 2012 Wiley Periodicals, Inc.     

Common and unique structural plasticity after left and right hemisphere stroke

Strokes to the left and right hemisphere lead to distinctive behavioral profiles. Are left and right hemisphere strokes (LHS and RHS) associated with distinct or common poststroke neuroplasticity patterns? Understanding this issue would reveal hemispheric neuroplasticity mechanisms in response to brain damage. To this end, we investigated poststroke structural changes (2 weeks to 3 months post-onset) using longitudinal MRI data from 69 LHS and 55 RHS patients and 31 demographic-matched healthy control participants. Both LHS and RHS groups showed statistically common plasticity independent of the lesioned hemisphere, including 1) gray matter (GM) expansion in the ipsilesional and contralesional precuneus, and contralesional superior frontal gyrus; 2) GM shrinkage in the ipsilesional medial orbital frontal gyrus and middle cingulate cortex. On the other hand, only RHS patients had significant GM expansion in the ipsilesional medial superior and orbital frontal cortex. Importantly, these common and unique GM changes post-stroke largely overlapped with highly-connected cortical hub regions in healthy individuals. Moreover, they correlated with behavioral recovery, indicating that post-stroke GM volumetric changes in cortical hubs reflect compensatory rather than maladaptive mechanisms. These results highlight the importance of structural neuroplasticity in hub regions of the cortex, along with the hemispheric specificity, for stroke recovery.     

Visual neglect as a predictor of functional outcome one year after stroke

OBJECTIVE: The aim was to study the role of visual neglect in acute right hemisphere brain infarct as a predictor of poor functional outcome during the first year after stroke. In particular, we were interested in the additional value of neglect measures besides hemiparesis, hemianopia, cognitive deficits and age. PATIENTS AND METHODS: A consecutive series of 57 patients with a neuroradiologically verified right hemisphere infarct was examined within 10 days of the stroke. Fifty patients were followed up for 1 year. Neglect was measured with the Conventional and the Behavioural subtests of the Behavioural Inattention Test (BITC and BITB, respectively). The predictors were determined at the 10-day examination. Functional outcome was assessed 3, 6 and 12 months after the onset with the Frenchay Activities Index. RESULTS: Neglect in BITB was the best single predictor, which together with high age formed the best combination of predictors for poor functional outcome at each follow-up. Hemiparesis was also included in this prediction model at the 3-month follow-up, but hemianopia, BITC, or visuoconstructional and memory deficits showed no additional predictive value. However, neglect usually recovered soon. When neurological and cognitive deficits were assessed at the same time as the outcome, hemiparesis rather than neglect was the strongest correlate of poor outcome. CONCLUSION: Neglect in acute stroke is an important predictor of poor functional recovery. Residual neglect, which could be compensated in the follow-up tests, may nevertheless restrict patients' real-life activities and hobbies.     

Motor deficits after left or right hemisphere damage due to stroke or tumor

The motor performance of 29 tumor and 43 stroke patients with unilateral left or right hemisphere damage and 40 non-brain-damaged control subjects was compared on six motor tasks. Grip strength, finger tapping, static and vertical groove steadiness, maze coordination and grooved pegboard tasks were administered. All brain-damaged groups performed more poorly than the control group on the hand contralateral to the lesion on all tasks and on the hand ipsilateral to the lesion on the tasks which required greater sensory-motor interaction (static and vertical groove steadiness, maze coordination and grooved pegboard). This pattern of results was the same for the patients with left or right hemisphere damage and was best explained by the hypothesis that the tasks which require greater sensory-motor interaction require more neural control and are more likely to be disrupted after brain damage, regardless of lateralization.     

Acute aphasia after right hemisphere stroke

Right hemispheric stroke aphasia (RHSA) rarely occurs in right- or left-handed patients with their language representation in right hemisphere (RH). For right-handers, the term crossed aphasia is used. Single cases, multiple cases reports, and reviews suggest more variable anatomo-clinical correlations. We included retrospectively from our stroke data bank 16 patients (right- and left-handed, and ambidextrous) with aphasia after a single first-ever ischemic RH stroke. A control group was composed of 25 successive patients with left hemispheric stroke and aphasia (LHSA). For each patient, we analyzed four modalities of language (spontaneous fluency, naming, repetition, and comprehension) and recorded eventual impairment: (1) on admission (hyperacute) and (2) between day 3 and 14 (acute). Lesion volume and location as measured on computed tomography (CT) and magnetic resonance imaging (MRI) were transformed into Talairach stereotaxic space. Nonparametric statistics were used to compare impaired/nonimpaired patients. Comprehension and repetition were less frequently impaired after RHSA (respectively, 56% and 50%) than after LHSA (respectively, 84% and 80%, P = 0.05 and 0.04) only at hyperacute phase. Among RHSA, fewer left-handers/ambidextrous than right-handers had comprehension disorders at second evaluation (P = 0.013). Mean infarct size was similar in RHSA and LHSA with less posterior RHSA lesions (caudal to the posterior commissure). Comprehension and repetition impairments were more often associated with anterior lesions in RHSA (Fisher’s exact test, P < 0.05). Despite the small size of the cohort, our findings suggest increased atypical anatomo-functional correlations of RH language representation, particularly in non-right-handed patients.     

Prolonged muscular flaccidity: frequency and association with unilateral spatial neglect after stroke

The frequency of prolonged muscular flaccidity (PMF) was examined in a series of stroke patients in chronic phase suffering from hemiplegia with minimal spontaneous recovery (MSR). The results indicated that in such a population with poor motor recovery, PMF was significantly more frequent than spasticity. PMF was found to be associated with left-sided hemiplegia and unilateral spatial neglect. The minimal spontaneous recovery of the series of stroke patients we studied could be dependent on the interaction of three negative prognostic factors: left sided hemiplegia, unilateral spatial neglect and prolonged muscular flaccidity.     

Word-category specific deficits after lesions in the right hemisphere

A speeded lexical decision task was used to investigate word-category deficits in patients suffering from lesions in the right hemisphere and in neurological controls without cortical lesion. In all patients from one group (n = 12), the right frontal lobe was affected causing a left-sided hemiparesis. In the second group (n = 6), lesions primarily affected areas in the right inferior temporo-occipital lobes. Patients with motor deficits due to lesions in the spinal cord or in the periphery served as neurological controls (n = 9). Processing of three categories of words was investigated: verbs referring to actions (action verbs (acVs)); nouns with strong visual associations (visually-related nouns (viNs)); and nouns with both strong action and visual associations (bimodal nouns (biNs)). Stimulus categories were matched for word length and normalized lexical frequency. Error scores revealed a significant word category by patient group interaction. Patients with lesions in the right frontal lobe showed most severe deficits in processing action verbs, whereas those with lesions in their right temporo-occipital areas showed most severe deficits in processing visually-related nouns. Neurological controls did not show any differences between word categories. The double dissociation of the processing impairments seen in frontal versus temporo-occipital patients demonstrates that specific word-category deficits can arise from lesions in the right non-dominant hemisphere. An account for these results in terms of distributed neuronal systems representing words is offered.     

Social participation following right hemisphere stroke: influence of a cognitive-communication disorder

Background: The ability to return to social activities and roles is an important focus of rehabilitation for people affected by stroke. Rehabilitation professionals currently have limited evidence on the impact of a cognitive-communication disorder (CCD) following right hemispheric (RH) stroke on social participation, and how to support return to social activities and roles.

Aims: This study describes (1) social participation change as reported by people with RH stroke; (2) compares social participation change across two groups based on the presence or absence of CCD following RH stroke; and (3) compares self and proxy reports of changes in participation.

Methods & Procedures: A telephone survey was conducted with randomly selected people with first onset, unilateral RH stroke, and with matched significant others (proxies). The Sydney Psychosocial Reintegration Scale (SPRS-2) was utilised to explore change associated with stroke across Occupational Activities (OA), Interpersonal Relationships (IR) and Independent Living Skills (LS). Survey responses were compared utilising independent t-tests across two groups based on the presence or absence of CCD. Participant-proxy agreement was established using inter-rater correlation coefficient.

Outcomes & Results: Change in social participation was reported for thirty-six participants with an average age of 65.95 years (SD = 13.09), of whom 58.3% were male and 38.9% employed at the time of the stroke. Time post-stroke to completion of the SPRS-2 ranged from six to 33 months. Most participants (94.4%, n = 34) reported change in at least one of the SPRS-2 domains. The presence of CCD had an impact on social participation as measured on the SPRS-2, which was significantly different to what was reported by participants without a communication impairment post-RH stroke (p = 0.02.) Inter-rater agreement statistic (Kappa) indicated a fair participant-proxy dyad agreement in the group with CCD, and a moderate agreement in the group without CCD across the SPRS-2 domains.

Conclusions: Changes in social participation following RH stroke occur across Occupational Activities, Interpersonal Relationships and Independent Living Skills for the majority of people and occur with greater frequency and degree where a CCD is present. This exploratory study highlights the importance of rehabilitation goals that address social participation to reduce potential social isolation in people with CCD post-RH stroke. Further identification of risk factors for social participation restriction in this population is required to better inform rehabilitation timing and focus.     

Reduction in cerebral activation after right hemisphere stroke

Destruction or disconnection of specific neuronal structures or failure to activate those structures may impair brain function. Because the right hemisphere seems dominant for mediating arousal, which is an important determinant of the capacity for cerebral activation, we predicted that subjects with right hemisphere damage would have a greater reduction in the capacity for cerebral activation than subjects with left hemisphere damage. A paradigm requiring that two simple tasks be performed singly and simultaneously was used to assess the capacity for activation. Subjects with right hemisphere damage had significantly greater impairment in the capacity for cerebral activation than subjects with left hemisphere damage. This impairment may partly explain the associations between right hemisphere damage and decreased ability to perform certain analytic and linguistic tasks.