Contraversive Pushing Research Articles

Scale for Contraversive Pushing: Cutoff Scores for Diagnosing “Pusher Behavior” and Construct Validity

Considerable disagreement exists among researchers with regard to the prevalence, pathophysiology, and treatment of "pusher behavior" (PB), partly because of different testing procedures. This study was primarily aimed at establishing cutoff scores for and the construct validity of the Scale for Contraversive Pushing (SCP). The prevalence of PB in people with right- and left-brain lesions also was investigated. The study subjects were 105 consecutive patients with recent stroke. Two methods were used to diagnose PB: clinical examination and SCP score with 3 different cutoff points--an SCP total score of greater than 0 (Crit_1), subscores in each section of the scale of greater than 0 (Crit_2), and subscores in each section of the scale of > or =1 (Crit_3). Clinical and SCP diagnoses were independently made by different examiners. The Cohen kappa coefficient was used to determine the agreement between clinical and SCP diagnoses. The construct validity of the SCP was estimated by calculation of Spearman rank correlation coefficients for SCP and balance, mobility, and functional scores. The agreement between clinical and SCP diagnoses was low (kappa=.212) when Crit_1 was used. Crit_2 led to the highest agreement with the clinical diagnosis (kappa=.933). However, only Crit_3, although globally less accurate (kappa=.754), ensured no false-positive results. The construct validity of the SCP was demonstrated by significant (P<.001) moderate to high correlations with mobility (rho=.595), functional (rho=.632), and balance (rho=.666) scores. The prevalence of PB was not influenced by the side of the lesion. A limitation of the study was that the reliability of the clinical examination method was not investigated. The results support the validity of the SCP and suggest the need to choose different SCP cutoff criteria (Crit_2 or Crit_3) according to the aim of the evaluation.

Physiotherapeutic aspects and prognostic of Pusher Syndrome

Pusher Syndrome (PS) is an alteration of postural control characterized by a disorder of vertical body perception relative to gravity,in which patients push the body laterally using the non-paretic hemibody. It has not been much studied and there are still controversies in theliterature regarding therapeutic and prognostic aspects. The aim of this work was checking these therapeutic and prognostic factors. For doingthat, a literature survey was done by means of simple inquiries in the bases Medline, Embase, Pubmed, Lilacs, EBM, Cochrane, Peter, Scielo, Portalda Pesquisa and Informa World, with the keywords pusher syndrome, contraversive pushing and pusher behavior. Clinical papers were includedwith therapeutic and / or prognostic approach in all languages. Clinical papers were excluded with etiologic, physiopathologic and diagnosticapproaches. Altogether, 341 references were found and 8 clinical papers were found that filled the inclusion criteria. Only 2 studies describedthe used therapeutic methodology, which consisted in visual feedback on the correct vertical posture, since vertical visual perception seems topersist but transfer of weight and march training were skills absent in these patients, who move the body laterally. Apparently, the syndromehas a good prognostic, with reduced or absent symptoms from 2 to 6 months after the beginning of rehabilitation. The associated presence ofheminegligence and the etiology of injury seem to compromise prognostic. This therapeutic strategy had satisfactory results, but more randomizedstudies are necessary to prove its efficiency and impact on Pusher Syndrome prognostic.

Clinical Assessment Scale for Contraversive Pushing, interrater reliability of a Swedish version

Pusher syndrome in patients with stroke is a postural disorder with the patients actively pushing themselves towards their paretic side. Different methods have been used for assessing its presence and severity. The aim of this study was to translate the most frequently used scale, the Clinical Assessment Scale for Contraversive Pushing (SCP), into Swedish and to investigate the interrater reliability. Twenty-two patients in the acute phase after stroke onset, with signs of pushing, were consecutively included in the study. Two physiotherapists assessed the same patient on different occasions but on the same day. Almost all patients were assessed on more than one day. Four physiotherapists were involved in the study. In total, those four physiotherapists made 60 paired assessments on these 22 patients. Intraclass correlation 2.1 ranged from 0.732 to 0.856, and showed good reliability in calculated variables and the total score. Kappa coefficients ranged from 0.609 to 0.788 and showed good reliability in ca...

Pushing behavior and hemiparesis: which is critical for functional recovery in pusher patients ? Case report

We report a sequential neuroimaging study in a 48-years-old man with a history of chronic hypertension and lacunar strokes involving the ventral lateral posterior nucleus of the thalamus. The patient developed mild hemiparesis and severe contraversive pushing behavior after an acute hemorrhage affecting the right thalamus. Following standard motor physiotherapy, the pusher behavior completely resolved 3 months after the onset and, at that time, he had a Barthel Index of 85, although mild left hemiparesis was still present. This case report illustrates that pushing behavior itself may be severely incapacitating, may occur with only mild hemiparesis and affected patients may have dramatic functional improvement (Barthel Index 0 to 85) after resolution pushing behavior without recovery of hemiparesis.

Postural abnormalities and contraversive pushing following right hemisphere brain damage

We investigated the presence of postural abnormalities in a consecutive sample of stroke patients, with either left or right brain damage, in relation to their perceived body position in space. The presence or absence of posture-related symptoms was judged by two trained therapists and subsequently analysed by hierarchical classes analysis (HICLAS). The subject classes resulting from the HICLAS model were further validated with respect to posture-related measurements, such as centre of gravity position and head position, as well as measurements related to the postural body scheme, such as the perception of postural and visual verticality. The results of the classification analysis clearly demonstrated a relation between the presence of right brain damage and abnormalities in body geometry. The HICLAS model revealed three classes of subjects: The first class contained almost all the patients without neglect and without any signs of contraversive pushing. They were mainly characterised by a normal body axis in any position. The second class were all neglect patients but predominantly without any contraversive pushing. The third class contained right brain damaged patients, all showing neglect and mostly exhibiting contraversive pushing. The patients in the third class showed a clear resistance to bringing the weight over to the ipsilesional side when the therapist attempted to make the subject achieve a vertical posture across the midline. The clear correspondence between abnormalities of the observed body geometry and the tilt of the subjective postural and visual vertical suggests that a patient's postural body geometry is characterised by leaning towards the side of space where he/she feels aligned with an altered postural body scheme. The presence of contraversive pushing after right brain damage points in to a spatial higher-order processing deficit underlying the higher frequency and severity of the axial postural abnormalities found after right brain lesions.

The Scale for Contraversive Pushing: A Reliability and Validity Study

Objective. Pushing toward the hemiplegic side can interfere with mobility training after stroke. This study estimated the internal consistency, interrater reliability, and validity of the Scale for Contraversive Pushing (SCP). Methods. Twenty-six patients with recent stroke were diagnosed with pusher behavior (PB). Two testers, randomly selected from 3 other examiners, independently assessed each patient using the SCP on the same day within 3 days of admission for rehabilitation. Cohen kappa coefficient was used to determine the agreement between the clinical and SCP diagnosis. The interrater reliability of the scale was estimated by calculation of the intraclass correlation coefficient. Cronbach’s alpha coefficient and Pearson’s coefficients were used to estimate the internal consistency of the scale and correlations between the subscores and the total score. Results. The agreement between SCP and clinical diagnosis was very low when the original cutoff criterion for SCP diagnosis was used but was almost perfect with a modified criterion. The interrater reliability was good to excellent with regard both to each sub-score and to the total score. The internal consistency was very high, along with correlations between subscores and total score of the scale. Conclusions. The results provide support for use of the SCP based on its reliability and validity using a modified cutoff criterion to make a diagnosis of PB.

"Pusher syndrome" following cortical lesions that spare the thalamus

Stroke patients with "pusher syndrome" show severe misperception of their own upright body orientation although visual-vestibular processing is almost intact. This dissociation argues for a second graviceptive system in humans for the perception of body orientation. Recent studies revealed that the posterior thalamus is an important part of this system. The present investigation aimed to study the cortical representation of this system beyond the thalamus. We evaluated 45 acute patients with and without contraversive pushing following left-or right-sided cortical lesions sparing the thalamus. In both hemispheres, the simple lesion overlap associated with contraversive pushing typically centered on the insular cortex and parts of the postcentral gyrus. The comparison between pusher patients and controls who were matched with respect to age, lesion size, and the frequency of spatial neglect, aphasia and visual field defects revealed only very small regions that were specific for the pusher patients with cortical damage sparing the thalamus. Obviously, the cortical structures representing our control of upright body orientation are in close anatomical proximity to those areas that induce aphasia in the left hemisphere and spatial neglect in the right hemisphere when lesioned. We conclude that in addition to the subcortical area previously identified in the posterior thalamus, parts of the insula and postcentral gyrus appear to contribute at cortical level to the processing of the afferent signals mediating the graviceptive information about upright body orientation.

Pusher syndrome: Reliability, validity and sensitivity to change of a classification instrument

Stroke patients with “pusher syndrome” actively push away from the non-paretic side, leading to postural imbalance. The Clinical Scale for Contraversive Pushing (SCP) is the only known instrument developed to evaluate the degree of pushing, but its reliability and validity has not been evaluated. A pilot study of the Swedish version showed that the instrument needed modification. The main purpose of this study was to investigate the interrater reliability and validity of the modified SCP. In addition, the purpose was to determine the change in pushing and functional ability during the acute rehabilitation period. Nineteen consecutive patients exhibiting pushing after stroke were tested before and after the rehabilitation. Berg's Balance Scale and S-COVS were used to study concurrent validity and functional ability. Interrater reliability was measured using Kappa and Spearman's rho. The kappa value was 0.51 before, 0.73 after, and rs was 0.82/0.94. Concurrent validity as determined by Spearman's rho was rs...

Controle postural na síndrome de Pusher: influência dos canais semicirculares laterais

A síndrome de Pusher caracteriza-se por uma alteração do equilíbrio na qual pacientes com lesões encefálicas empurram-se em direção ao lado parético utilizando o membro não-afetado. O papel do sistema vestibular na alteração postural da síndrome de Pusher ainda não foi devidamente elucidado. OBJETIVO: Neste estudo objetivamos avaliar o papel dos canais semicirculares horizontais na expressão clínica da síndrome de Pusher, através da aplicação das provas calórica e rotatória. FORMA DE ESTUDO: Observacional, clínico e prospectivo. MATERIAL E MÉTODO: Avaliamos 9 pacientes com AVC e síndrome de Pusher internados na Enfermaria de Neurologia do HCFMRP-USP. Os pacientes foram submetidos à avaliação neurológica clínica e neuropsicológica, NIHSS, Scale for Contraversive Pushing - SCP, teste calórico e teste rotatório. RESULTADOS: Foram estudados 9 pacientes (5 homens) com idade média de 71,8 ± 5,9 anos e com NIHSS médio de 18.33. Três pacientes apresentaram preponderância direcional contralateral à lesão encefálica na prova calórica. Na prova rotatória, foram observados quatro pacientes com preponderância direcional na análise de velocidade da componente lenta. CONCLUSÃO: Os resultados do presente estudo indicam que a disfunção dos canais semicirculares não parece ser fundamental para a expressão da síndrome de Pusher.

Posture control in Pusher syndrome: influence of lateral semicircular canals

SummaryPusher syndrome is an interesting disorder of balance in patients with encephalic lesions characterized by the peculiar behavior of actively pushing away from the non-hemiparetic side and resisting against passive correction, with a tendency to fall toward the paralyzed side. The role of vestibular system on the pushing behavior is not clear. Aim: To evaluate horizontal semicircular canal function in patients with Pusher syndrome, using caloric and rotation tests. Study Design: Observational prospective. Material and Method: We evaluated 9 inpatients with stroke and Pusher syndrome at the neurological unit of HCFMRP-USP. We applied neurological and neuropsychological exams, NIHSS, Scale for contraversive pushing (SCP), caloric and rotation tests. Results: We evaluated 9 patients (5 men) with mean age of 71.8 ± 5.9 and mean NIHSS of 18.33. Three patients presented contralateral directional preponderance on caloric test and we found four patients with directional preponderance on analysis of the slow phase velocity of rotation test response. Conclusion: Our findings indicate that a dysfunction of semicircular canals does not seem to be relevant for the clinical manifestations of the Pusher syndrome.

Contraversive Pushing and Inattention of the Contralesional Hemispace

The aim of this study was to investigate, in 114 stroke patients, the frequency of occurrence of a largely unknown neurological disorder, characterized by a postural imbalance due to a ‘pushing away’ reaction of the body towards the contralesional side of space, in function of hemispheric lesion localization and gender. The study also investigate the relation of this contraversive pushing with active movement, somatosensory perception deficits and, in particular, inattention of contralesional hemispace and body. The similarity of the presence of contraversive pushing and the syndrome of spatial hemineglect together with a gender-related differentiation suggest the existence of a “pusher syndrome”, in which the pathophysiology points in the direction of a spatial higher-order processing deficit, related to spatial inattention, underlying the higher frequency and severity of contraversive pushing after right brain lesions. This project was funded by a Special Doctoral Grant of the Fund for Scientific Research (F.W.O.) - Flanders, Belgium.

Posterior thalamic hemorrhage induces “pusher syndrome”

Recent findings argue for a pathway in humans for sensing the orientation of gravity and controlling upright body posture, separate from the one for orientation perception of the visual world. Stroke patients with contraversive pushing were shown to experience their body as oriented upright when actually tilted about 20 degrees to the ipsilesional side, in spite of normal visual-vestibular functioning. A recent study suggested the involvement of posterolateral thalamus typically associated with the disorder. To evaluate the relationship between pushing behavior and thalamic function. Over a 3-year period the authors prospectively investigated 40 patients with left- or right-sided thalamic strokes. Twenty-eight percent showed contraversive pushing. The authors found a strong relationship between etiology, vascular territory, lesion size, and neurologic disorders associated with contraversive pushing. Pusher patients had larger lesions that typically were caused by hemorrhage (vs infarcts) located in the posterior thalamus (vs anterior thalamic lesions in those patients without pushing behavior). A paresis of the contralesional extremities was more frequent and more severe in pusher patients. Further, these patients showed more additional spatial neglect with right thalamic lesions, while they tended to be more aphasic with left thalamic lesions. Posterior thalamus seems to be fundamentally involved in our control of upright body posture. Higher pressure, swelling, and other secondary pathologic processes associated with posterior thalamic hemorrhage (vs thalamic infarction) may provoke contraversive pushing in combination with additional neurologic symptoms.

Contraversive pushing in non-stroke patients

Pusher syndrome is a disorder of postural control observed in patients with right or left brain damage associated with hemiparesis. Those patients show a peculiar behavior of actively pushing away from the nonhemiparetic side and resisting against passive correction, with a tendency to fall toward the paralyzed side. Thus far this phenomenon has been exclusively associated with stroke patients. We investigate the occurrence, imaging features and clinical evolution of pusher behavior in patients with acute encephalic lesions at a tertiary emergency hospital. Pusher patients were identified from 530 inpatients during a 1 year period. Patients were evaluated using a standardized Scale for Contraversive Pushing (SCP), neurological examination, assessment of neuropsychological symptoms, activities of daily living function and neuroimaging studies. We found eight patients (1.5%) with severe contraversive pushing, three female and five male. Age at symptoms onset ranged from 48 to 80 years (mean 65.4). All patients had scores equal or above 1.5 in each tested parameter of the SCP. Six patients (75 %) had right-hemisphere brain damage. A stroke etiology was found in four patients. The other four patients had non-stroke etiology (three traumatic, one metastatic tumor). Stroke patients showed complete recovery of pusher behavior at a mean duration of 15.3 weeks. In patients with brain trauma, pushing behavior was completely resolved in a mean time of 5 weeks. The results demonstrate that contraversive pushing may also occur in patients with non-stroke neurological lesions and suggest that resolution of symptoms may vary according to the underlying etiology.

Prognosis of contraversive pushing.

Stroke patients with 'pusher syndrome' actively push away from the non-hemiparetic side leading to a loss of postural balance and falling towards the paralysed side. The behaviour is due to an altered perception of the body's orientation in relation to gravity. Here, we studied the prognosis of the disorder. Twelve pusher patients first investigated immediately after the stroke were re-examined 6 months later. Pusher symptoms had nearly completely recovered. The aim for physiotherapy of patients with contraversive pushing thus is to shorten the period of necessary treatment and enable earlier discharge from residential care.

Clinical symptoms, origin, and therapy of the "pusher syndrome"

Stroke patients may exhibit the peculiar behavior of actively pushing away from the nonhemiparetic side, leading to lateral postural imbalance and a tendency to fall towards the paralyzed side. These patients use the nonparetic extremities to stem actively against attempts of passive correction towards upright orientation. This phenomenon has been called the "pusher syndrome". Recent findings disclose that the deficit leading to contraversive pushing is an altered perception of the body's orientation in relation to gravity. Pusher patients experience their body as upright when they are actually tilted to the nonhemiparetic side. In contrast, processing of visual and vestibular inputs for the determination of visual vertical was undisturbed. The results argue for a separate pathway in humans for sensing gravity apart from that for perception of the visual world. This second graviceptive system decisively contributes to our control of upright body posture. The present article describes this still largely unknown neurological disease. The clinical examination of contraversive pushing, its underlying disturbance, lesion location, and approaches for therapy are considered.

The neural representation of postural control in humans.

Lesion of the "vestibular cortex" in the human posterior insula leads to a tilted perception of visual vertical but not to tilted body posture and loss of lateral balance. However, some stroke patients show the reverse pattern. Although their processing of visual and vestibular inputs for orientation perception of the visual world is undisturbed, they push away actively from the ipsilesional side (the side of lesion location), leading to a contraversive tilt of the body (tilt toward the side opposite to the lesion) and falling to that side. Recently, the origin of contraversive pushing was identified as an altered perception of the body's orientation in relation to gravity. These patients experience their body as oriented "upright" when actually tilted enormously to the ipsilesional side (18 degrees on average). The findings argued for a separate pathway in humans for sensing body orientation in relation to gravity apart from the one projecting to the vestibular cortex. The present study aimed at identifying this brain area. The infarcted brain regions of 23 consecutively admitted patients with severe contraversive pushing were projected onto a template MRI scan, which had been normalized to Talairach space. The overlapping area of these infarctions centered on the posterolateral thalamus. Our finding necessitates reinterpretation of this area as being only a "relay structure" of the vestibular pathway on its way from the brainstem to the vestibular cortex. The ventral posterior and lateral posterior nuclei of the posterolateral thalamus (and probably its cortical projections) rather seem to be fundamentally involved in the neural representation of a second graviceptive system in humans decisive for our control of upright body posture.

The origin of contraversive pushing: evidence for a second graviceptive system in humans.

Stroke patients may exhibit the peculiar behavior of actively pushing away from the nonhemiparetic side, leading to lateral postural imbalance and a tendency to fall toward the paralyzed side. This phenomenon has been called the "pusher syndrome." The current study analyzes the mechanism leading to contraversive pushing. The subjective postural vertical (SPV) and subjective visual vertical (SVV) were determined in five consecutively admitted patients with severe contraversive pushing and in controls. Whereas adjustment of the SPV reflects the perceived upright orientation of the body, the SVV provides a sensitive and direction-specific measurement of peripheral and central vestibular dysfunction. The deficit leading to contraversive pushing is an altered perception of the body's orientation in relation to gravity. Pusher patients experience their body as oriented "upright" when it is tilted 18 degrees to the nonhemiparetic, ipsilesional side. In contrast, perception of the SVV was undisturbed. A separate pathway seems to be present in humans for sensing the orientation of gravity apart from the one for orientation perception of the visual world. This second graviceptive system decisively contributes to humans' control of upright body posture. Contraversive pushing occurring after stroke lesions may represent the behavioral correlate of a disturbed neural representation of this system.