Which are the primary CP classifications by muscle tone?

• A. Spastic, Dyskinetic, Ataxic, Mixed, and Atonic/hypotonic.
• B. Only Spastic CP.
• C. CP types are based on age of onset.
• D. All CP types are the same.

Answer: (A)

In cerebral palsy, movement disorders are most usefully described by the pattern of muscle tone. Spastic CP is the most common, with increased muscle tone that makes movements stiff and resistant to passive stretch, often producing a stiff, scissoring posture. Dyskinetic CP involves involuntary, fluctuating movements such as dystonia or choreoathetoid patterns, with variable tone across different muscles and a shakier or less controlled movement quality, usually reflecting basal ganglia involvement. Ataxic CP is driven by cerebellar involvement and presents with balance and coordination problems, often with low or unstable tone, wide-based gait, and intention tremor. Mixed CP describes individuals who exhibit a combination of these tone patterns, showing features from more than one category. Atonic or hypotonic CP features reduced muscle tone, resulting in floppy posture and poor antigravity control.

These classifications are not about onset age, and CP types are not all the same; there are distinct tone patterns that guide assessment and management, and many people show more than one pattern rather than a single pure type.