Spastic

Spastic is a medical adjective used to describe conditions related to spasticity—a specific type of increased muscle tone, or stiffness, caused by uncontrolled contractions of skeletal muscles. The term originates from the Greek spastikos, meaning "drawing in," which aptly describes the tight, pulling sensation of the affected muscles.

Spasticity is not a disease itself but a symptom of underlying damage to the central nervous system (the brain or spinal cord). It is a key feature in several neurological conditions, most notably spastic cerebral palsy.

Understanding Spasticity

Spasticity is more than just muscle tightness; it is a neurological condition resulting from damage to the upper motor neurons. These neurons are part of the central nervous system and are responsible for controlling voluntary movement by sending signals from the brain down the spinal cord to the muscles.

A crucial part of their function is to send inhibitory (calming) signals that prevent muscles from becoming too tight. When these upper motor neurons are damaged, this inhibition is lost. The result is an imbalance of signals, leading to overactive reflexes and an abnormal increase in muscle tone.

Key characteristics of spasticity include:

Hypertonia: Increased muscle tone, causing stiffness and resistance to movement.
Velocity-Dependence: The muscle stiffness is more pronounced when a limb is moved quickly and less pronounced when moved slowly.
Hyperreflexia: Exaggerated deep tendon reflexes, such as a very brisk knee-jerk reaction.
Clonus: A series of rapid, rhythmic, involuntary muscle contractions and relaxations, often seen as a tapping of the foot.
Clasp-Knife Response: A phenomenon where there is strong initial resistance to passive stretching of a limb, which then suddenly gives way, much like closing a pocketknife.

Associated Conditions

Spasticity is a common symptom of several neurological disorders that affect the brain or spinal cord.

Spastic Cerebral Palsy: This is the most common type of cerebral palsy, affecting around 80% of individuals with the condition. It is caused by damage to the brain's motor cortex before, during, or shortly after birth. The resulting spasticity can affect one limb, one side of the body (spastic hemiplegia), primarily the legs (spastic diplegia), or all four limbs (spastic quadriplegia).
Stroke: Damage to the brain from a stroke can disrupt motor control pathways, leading to spasticity on one side of the body.
Multiple Sclerosis (MS): The demyelination (damage to the protective coating of nerves) in the brain and spinal cord caused by MS can interfere with nerve signals, resulting in spasticity.
Spinal Cord Injury (SCI): Injury to the spinal cord interrupts the flow of signals between the brain and the body below the level of the injury, often leading to severe spasticity.
Traumatic Brain Injury (TBI): Similar to a stroke, physical trauma to the brain can damage motor pathways and cause spasticity.

Management and Treatment

The goal of managing spasticity is to reduce stiffness and pain, improve function and mobility, and prevent long-term complications like joint deformities (contractures). Treatment is multidisciplinary and tailored to the individual.

Physical and Occupational Therapy: This is the cornerstone of management. It includes a program of stretching, strengthening exercises, and functional training to maintain range of motion and improve motor skills. Bracing or casting may also be used to help position limbs correctly.
Oral Medications: Muscle relaxant medications like baclofen, tizanidine, or diazepam can be used to reduce overall muscle tone. However, they can cause systemic side effects such as drowsiness.
Botulinum Toxin (Botox) Injections: For spasticity localized to specific muscle groups, targeted injections of Botox are highly effective. The toxin temporarily weakens the overactive muscles, reducing stiffness and improving range of motion.
Intrathecal Baclofen (ITB) Pump: In cases of severe, widespread spasticity, a small pump can be surgically implanted in the abdomen to deliver the medication baclofen directly into the spinal fluid. This allows for a much lower dose with fewer side effects than oral medication.
Surgery: In some severe cases, orthopedic surgery (e.g., tendon lengthening) or neurosurgery (e.g., selective dorsal rhizotomy) may be considered to provide more permanent relief.

Note on Terminology

While "spastic" is a valid and necessary medical term, it has historically been co-opted as a derogatory slur, particularly in the United Kingdom, to insult people with disabilities, especially cerebral palsy. For this reason, outside of a clinical context, the term is widely considered offensive and inappropriate. Medical professionals and disability advocates recommend using person-first language, such as "a person with spasticity" or "an individual with spastic cerebral palsy."