Pusher
Syndrome
What is it?
A
unique presentation of abnormal body posture seen in approximately 5-10% of
post-stroke patients . First
described by Patricia Davis in 1985, ‘Pusher Syndrome’ is a term used to
describe the behaviour of individuals using their non-paretic limb to push
themselves towards their paretic side. Left unsupported, these patients
demonstrate a loss in lateral posture, falling on to their paretic side. Pusher
Syndrome is often accompanied by severe inattention and hemisensory impairments.
What causes it?
Despite
the increase in investigation in the causes and symptoms of Pusher Syndrome it
is still a poorly understood presentation. It
has been suggested Pusher behaviour may be a result of a conflict between an
impaired somesthetic perception of vertical, and intact visual system or that
it may be a consequence of a high-order disruption of somatosensory information
processing from the paretic hemi-body. Patients
with Pusher Syndrome may also have primary visual or visual perceptual
problems, impaired proprioception, and motor impairments, which leave them less
able to relearn posture and balance.
Karnath
et al demonstrated that patients with Pusher Syndrome have a misperception of
their upright body posture; with patient’s reporting an “upright” posture when
actually tilted 18 degrees to the ipsilesional side. With MRI scanning, the
patients included in this study typically demonstrate left or right
posterolateral thalamus damage post stroke. However
the evidence around location of infarct is conflicting with some studies also
suggesting damage to the parietal area.
Abe et al also suggested that there could be increased prevalence of Pusher
Syndrome with right sided hemisphere damage. Paci et al in their review
suggested that the range of evidence in Pusher Syndrome may be due to a
multidimensional network responsible for upright postural control.
Diagnosis
Karnath and Broetz identify
three diagnostic factors of Pusher Syndrome, as shown below.
1) Spontaneous body posture- (severe/moderate and mild).
The patient’s initial posture shown immediately after a positional change
(ideally supine to sit/ sit to stand) must be assessed for contralateral
tilting. This can be seen with or without falling to the side contralateral to
the brain lesion. It is felt that patient’s must demonstrate this postural
abnormality regularly to be classified as suffering with Pusher Syndrome.
2) Abduction and
Extension of the Nonparetic Extremities-
Patients demonstrate abnormal positioning of the side ipsilateral to the brain lesion. Typically the hand will be abducted away from the body, the elbow held in extension and the hand searching for contact with a surface on which to push oneself to the perceived upright position. The lower limb may be abducted, with the knee and hip held in extension (as with the upper limb).
Patients demonstrate abnormal positioning of the side ipsilateral to the brain lesion. Typically the hand will be abducted away from the body, the elbow held in extension and the hand searching for contact with a surface on which to push oneself to the perceived upright position. The lower limb may be abducted, with the knee and hip held in extension (as with the upper limb).
3) Resistance to Passive
Correction of Tilted Posture-
Patients will typically actively resist against therapist’s manual interventions to correct their body posture. The patient’s extended upper and lower limbs will be used to push their weight towards their paretic side.
Patients will typically actively resist against therapist’s manual interventions to correct their body posture. The patient’s extended upper and lower limbs will be used to push their weight towards their paretic side.
Subsequently, the
Standardized Scale for Contraversive Pushing (SCP), has been formulated on
these 3 deficits. The SCP is a useful tool for clinicians to classify Pusher
Syndrome, and is quick and easy to apply in both an acute and rehabilitation
setting
Outcome Measures
- Burke Lateropulsion
Scale
This scale assesses the
patient’s resistance to:
1. Passive supine rolling
2. To passive postural correction when sitting and standing
3. To assistance during transferring and walking.
1. Passive supine rolling
2. To passive postural correction when sitting and standing
3. To assistance during transferring and walking.
The
score for each component s rated on a scale from 0 to 3 (0 to 4 for standing)
and the score is based on the severity of resistance or the tilt angle when the
patient begins to resist the passive movement. The score for diagnosis of
Pusher behaviour is ≥2 points
- Scale for Contraversive
pushing
This is made up of 3
components
1. The symmetry of spontaneous body posture (rated with 0, 0.25, 0.75, or 1 point)
2. The use of non-paretic extremities (0, 0.5, or 1 point),
3. The resistance to passive correction of the tilted posture (0 or 1 point).
1. The symmetry of spontaneous body posture (rated with 0, 0.25, 0.75, or 1 point)
2. The use of non-paretic extremities (0, 0.5, or 1 point),
3. The resistance to passive correction of the tilted posture (0 or 1 point).
For a diagnosis of Pusher
Syndrome all 3 components need to be present.
Bergmann
et al suggested that the Burke Lateropulsion Scale is more sensitive to small
changes in presentation and is more responsive in classifying Pusher behaviour
than the Scale for Contraversive Pushing. In addition it was suggested that the
Burke Lateropulsion Scale is especially useful to detect mild or resolving
pusher behaviour in standing and walking.
Rehabilitation
Karnath and Broetz suggested
that the first goal of initial rehabilitation is to provide visual feedback of
the patient’s altered body posture. By providing patients with visual information
in relation to their environment they are able to feel they are in an erect
posture when they see that they are tilted. While in different postural sets
patients should be asked whether they see if they are upright and given visual
references/ cues to help them orientate themselves to upright and given them
feedback about their body orientation. For example by using ground-vertical
structures- ie a therapist’s arm held upright to demonstrate true upright
orientation, a line on a wall or a door frame. Although patients with Pusher
Syndrome may initially need prompting with the use of visual feedback it is
hoped that, with regular therapy, patients are able to apply training
procedures independently and utilise their environment for gaining visual feedback
from vertical structures.
Karnath and Broetz
suggested from their clinical experience that the following sequence of
treatment may be effective in treatment of Pusher Syndrome:
•
Enable the patient to realize the disturbed perception of their body position.
• Enable the patient to visually explore their surroundings and the body's relationship to their environment and see whether he or she is oriented upright. Reference points can be used such as the therapist's arm or many vertical structures, such as door frames, windows or pillars.
• Practicing movements necessary to reach a vertical body position.
• Performing functional activities whilst maintaining a vertical body position.
• Enable the patient to visually explore their surroundings and the body's relationship to their environment and see whether he or she is oriented upright. Reference points can be used such as the therapist's arm or many vertical structures, such as door frames, windows or pillars.
• Practicing movements necessary to reach a vertical body position.
• Performing functional activities whilst maintaining a vertical body position.
Abe et al suggested that
when considering length of rehabilitation stay that laterality and prognosis of
Pusher Syndrome should be considered at the time of goal setting for
rehabilitation.
Prognosis
There are conflicting opinions in the literature with regards to
the persistence of Pusher Syndrome in the longer term and its impact on
functional outcome. Some authors report that the presence of Pusher Syndrome is
rarely seen 6 months post stroke and is shown to have no negative impact upon
patients’ ultimate functional outcome, although it has been shown to slow
rehabilitation by up to 3 weeks .
However, a case study by Santos-Pontelli et al reported the lingering presence of
Pusher Syndrome in 3 patients up to two years post-stroke, with profound
negative impacts upon their functional abilities.
In a
study by Babyar et al they reviewed whether the number of impairments patients
with Pusher Syndrome had, was a determinent on the level of recovery achieved From their findings they
proposed that 90.5% of patients studied with only a motor presentation were
able to 'recover' (scoring 0 or 1 in the Burke Lateropulsion Scale) from Pusher
Syndrome within 27 days. Those patients with with 2 deficits achieved the
target in about 59% of cases.For patients with motor, proprioceptive, and
visual–spatial impairments or hemianopia however, only 37% of patients were
able to achieve a score of 0 or 1 on the Burke Lateropulsion Scale prior to
discharge.
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