Spasticity in Multiple Sclerosis: Diagnosis and Management

Pathophysiology

Spasticity is a velocity‑dependent increase in muscle tone caused by upper motor neuron lesions; resistance rises with faster passive movement and typically shows a “clasp‑knife” release pattern. (International Journal of Stroke, 2016) 1

In adults with multiple sclerosis, spasticity presents as velocity‑dependent increased tone in anti‑gravity muscles (flexors of the upper limbs and extensors of the lower limbs). (International Journal of Stroke, 2016) 1
Patients experience painful muscle spasms that interfere with functional activities, positioning, and rehabilitation. (American Family Physician, 2017) 3
Rapid passive stretching aggravates spasticity, while slow movement alleviates it. (International Journal of Stroke, 2016) 1

Accurate diagnosis requires testing for velocity‑dependence during passive joint movement. (International Journal of Stroke, 2016) 1
Observation of the clasp‑knife phenomenon helps confirm spasticity rather than rigidity. (Praxis Medical Insights, 2026) 2

Stretching, range‑of‑motion exercises, proper positioning, and splinting are recommended as initial management. (International Journal of Stroke, 2016) 1

Botulinum toxin injections are the preferred pharmacologic option for focal spasticity of the upper or lower extremities and have demonstrated effectiveness. (American Family Physician, 2017) 3

Oral baclofen (30–80 mg/day divided into 3–4 doses), tizanidine, or dantrolene are recommended for generalized spasticity. (International Journal of Stroke, 2016) 1

Intrathecal baclofen therapy is advised for severe spasticity unresponsive to oral agents. (Praxis Medical Insights, 2026) 2

Rigidity in extrapyramidal disorders (e.g., Parkinson’s disease) is velocity‑independent and does not respond to antispasticity agents such as baclofen or botulinum toxin. (Praxis Medical Insights, 2026) 2

Dopaminergic therapy (levodopa/carbidopa) is the cornerstone of rigidity treatment. (Praxis Medical Insights, 2026) 2
Deep brain stimulation is an option for rigidity refractory to medication. (Praxis Medical Insights, 2026) 2

Misidentifying spasticity as rigidity can lead to inappropriate therapy; therefore, clinicians should prioritize velocity‑dependence testing and recognize the clasp‑knife sign to ensure correct treatment selection. (International Journal of Stroke, 2016) 1

Multiple sclerosis causes spasticity, not rigidity; employing antispasticity interventions (non‑pharmacologic measures, botulinum toxin, oral or intrathecal baclofen) is essential for optimal patient outcomes. (American Family Physician, 2017) 3