From the Guidelines
A positive Babinski sign is a significant indicator of upper motor neuron dysfunction, and when present, other neurological signs that should be tested for include hypertonia, hyper-reflexia, asterixis, and extrapyramidal dysfunction such as hypomimia, muscular rigidity, bradykinesia, and parkinsonian-like tremor 1.
Key Neurological Signs to Test
- Hypertonia: increased muscle tone, which can be assessed through passive movement of the limbs
- Hyper-reflexia: exaggerated deep tendon reflexes, which can be evaluated using a reflex hammer
- Asterixis: a flapping tremor, which can be elicited by having the patient hyperextend their wrists or rhythmically squeeze the examiner's fingers
- Extrapyramidal dysfunction: a range of symptoms including hypomimia, muscular rigidity, bradykinesia, and parkinsonian-like tremor, which can be assessed through observation and physical examination
Additional Considerations
In patients with a positive Babinski sign, it is also important to assess for cognitive impairment, personality changes, and disturbances of the sleep-wake cycle, as these can be associated with underlying conditions such as hepatic encephalopathy 1.
Neurological Examination
A comprehensive neurological examination should include an assessment of motor function, reflexes, and cognitive function, as well as evaluation for any focal neurological deficits 1.
From the Research
Neurological Signs to Test with a Positive Babinski Sign
When a patient presents with a positive Babinski sign, it is essential to test for other neurological signs to establish a comprehensive diagnosis. Some of these signs include:
- Decreased speed of foot tapping, which has been shown to be a reliable indicator of upper motor neuron dysfunction 2
- Plantar skin reflex, which is closely related to the Babinski reflex 3
- Cerebellar symptoms, such as:
- Cerebellar asynergy
- Adiadochokinesis
- Dysmetria
- Cerebellar catalepsy
- Rising sign 3
- Platysma sign, which is a sign of upper motor neuron dysfunction 4, 3
- Anosognosia, which is a condition where a patient is unaware of their neurological deficits 3
- Other reflexes, such as the Gordon, Chaddock, and Oppenheim reflexes, which can be used in combination with the Babinski reflex to increase reliability 5
Reliability and Validity of Neurological Signs
The reliability and validity of these signs are crucial in directing diagnosis and treatment. Studies have shown that:
- The Babinski sign has fair inter-rater reliability (kappa 0.30) and limited accuracy (agreement with known upper motor neuron weakness 56%) 2
- The combination of the Babinski and Chaddock reflexes is the most reliable 5
- Decreased speed of foot tapping has substantial inter-rater reliability (kappa 0.73) and high accuracy (agreement with known upper motor neuron weakness 85%) 2