From the Research
Brisk reflexes, also known as hyperreflexia, are typically caused by upper motor neuron dysfunction, which can occur in conditions such as stroke, multiple sclerosis, spinal cord injury, or amyotrophic lateral sclerosis, as supported by the most recent study 1. The causes of brisk reflexes can be attributed to various factors, including:
- Upper motor neuron lesions, which can disrupt the balance of supraspinal inhibitory and excitatory inputs directed to the spinal cord, leading to a state of disinhibition of the stretch reflex 2
- Conditions such as stroke, traumatic brain injury, multiple sclerosis, spinal cord injury, and cerebral palsy, which are common etiologies of upper extremity spasticity 3
- Spasticity, which is a component of the upper motor neuron syndrome, and can manifest as a velocity-dependent increase in resistance, i.e., hypertonia 1 When evaluating brisk reflexes, healthcare providers should perform a complete neurological examination to identify other signs of upper motor neuron damage, such as Babinski sign, spasticity, or muscle weakness. The presence of brisk reflexes on one side of the body may indicate a unilateral brain lesion, while bilateral brisk reflexes might suggest spinal cord pathology. Treatment depends on the underlying cause and may include medications to reduce spasticity, physical therapy, or addressing the primary condition, with botulinum toxin therapy being a preferred treatment for focal spasticity 1. Patients experiencing new-onset brisk reflexes should seek medical attention promptly as this may represent a significant neurological change requiring investigation.