Rare diseases · Sign or symptom
Postural instability
Balance impairment
HP:0002172
What it means
A tendency to fall or the inability to keep oneself from falling; imbalance. The retropulsion test is widely regarded as the gold standard to evaluate postural instability, Use of the retropulsion test includes a rapid balance perturbation in the backward direction, and the number of balance correcting steps (or total absence thereof) is used to rate the degree of postural instability. Healthy subjects correct such perturbations with either one or two large steps, or without taking any steps, hinging rapidly at the hips while swinging the arms forward as a counterweight. In patients with balance impairment, balance correcting steps are often too small, forcing patients to take more than two steps. Taking three or more steps is generally considered to be abnormal, and taking more than five steps is regarded as being clearly abnormal. Markedly affected patients continue to step backward without ever regaining their balance and must be caught by the examiner (this would be called true retropulsion). Even more severely affected patients fail to correct entirely, and fall backward like a pushed toy soldier, without taking any corrective steps.
Rare diseases that can present with this62
Very common80–99%
13- Atypical juvenile parkinsonism
- Classic progressive supranuclear palsy syndrome
- Episodic ataxia type 1
- Episodic ataxia with slurred speech
- Idiopathic bilateral vestibulopathy
- Manganese poisoning
- Mitochondrial membrane protein-associated neurodegeneration
- Primary dystonia, DYT13 type
- Primary progressive freezing gait
- Progressive supranuclear palsy
- Progressive supranuclear palsy-corticobasal syndrome
- Progressive supranuclear palsy-predominant parkinsonism syndrome
- Spinocerebellar ataxia type 6
Common30–79%
31- Autosomal recessive cerebellar ataxia due to STUB1 deficiency
- Autosomal recessive spastic paraplegia type 28
- Caribbean parkinsonism
- Cerebello-oculo-facio-genital syndrome
- Charcot-Marie-Tooth disease type 1E
- Cirrhosis-dystonia-polycythemia-hypermanganesemia syndrome
- CLN12 disease
- Cockayne syndrome type 1
- Cockayne syndrome type 2
- Corticobasal syndrome
- Cyanide-induced parkinsonism-dystonia
- Distal 17p13.1 microdeletion syndrome
- Episodic ataxia type 4
- Episodic ataxia type 5
- Familial or sporadic hemiplegic migraine
- Fragile X-associated tremor/ataxia syndrome
- Mal de débarquement
- Multiple system atrophy
- Multiple system atrophy, cerebellar type
- Multiple system atrophy, parkinsonian type
- Parkinsonian-pyramidal syndrome
- PLA2G6-related neurodegeneration, adult-onset
- PRKAR1B-related neurodegenerative dementia with intermediate filaments
- Rapid-onset dystonia-parkinsonism
- Spinocerebellar ataxia type 19/22
- Spinocerebellar ataxia type 41
- Spinocerebellar ataxia type 8
- Tay-Sachs disease
- X-linked dystonia-parkinsonism
- X-linked sideroblastic anemia and spinocerebellar ataxia
- Young-onset Parkinson disease
Sometimes5–29%
17- 15q11.2microdeletion syndrome
- Ataxia-oculomotor apraxia type 4
- Autosomal dominant spastic paraplegia type 9A
- Autosomal recessive cerebellar ataxia-epilepsy-intellectual disability syndrome due to RUBCN deficiency
- Central neurocytoma
- Full NF2-related schwannomatosis
- Hereditary late-onset Parkinson disease
- Mohr-Tranebjaerg syndrome
and 9 more in this range
The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.
Part of the broader category
Also called: Abnormal retropulsion test · Imbalance
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Start free with EleplanThis page uses the Human Phenotype Ontology (2026-06-23) — Human Phenotype Ontology Consortium, hpo.jax.org. Disease associations from Orphanet (INSERM), CC BY 4.0. Content is educational and is not medical advice.