The CDP battery
Motor Control & Adaptation
The SOT assesses sensory weighting. These two tests assess what comes next — the speed and quality of the motor response. The MCT measures the automatic reflex; the ADT measures the cerebellum's ability to refine that reflex across trials.
The Motor Control Test (MCT) gives unexpected forward and backward translations of the platform and times how long it takes the patient's body to react. The Adaptation Test (ADT) gives unexpected up-or-down tilts of the platform and measures whether the patient gets better at handling them across trials.
Together they cover two different motor competencies: the speed of the reflex loop and the cerebellum's capacity for motor learning.
MCT response latencies in healthy adults are ~90–130 ms for the leg-stretch reflex chain that corrects platform translation.3Prolonged latencies, symmetric, suggest central slowing — multiple sclerosis, post-stroke, Parkinson's. Asymmetric prolongation suggests a focal peripheral or central lesion on one side.
The ADT exposes cerebellar function specifically: a healthy adult attenuates sway across 4–5 repetitions of an unexpected platform tilt; a patient with cerebellar degeneration does not.2 The ADT is one of the few clinical bedside-equivalent tools that quantifies motor learning at this short timescale.
Direction-specific instability — particularly forward-back asymmetry — is a well-described Parkinson's fingerprint on the MCT and ADT, often preceding overt postural instability and useful as an early biomarker.1Interpreting the MCT alongside the LoS forward-excursion gives a coherent picture of bradykinetic and rigid postural control before clinical falls.
The ADT is also clinically useful in post-concussion management — failure to adapt despite symptom resolution may reflect persistent subclinical cerebellar processing change.4 A reasonable rule of thumb: an SOT with a clean sensory profile but an abnormal ADT raises the suspicion of cerebellar dysfunction even in the absence of frank ataxia.
Side-by-side comparison
Tap a tab to compare the two tests on perturbation, measurement and clinical use.
- Perturbation
- Horizontal translations of the platform, forward or back, delivered without warning.
- Amplitudes / repetitions
- Small · Medium · Large — repeated each amplitude.
- What is measured
- Response latency · Response amplitude · Left–right symmetry.
- Abnormal pattern
- Prolonged latencies (central slowing, neuropathy) or asymmetric latencies (focal lesion).
- Pictures it surfaces
- Multiple sclerosis · post-stroke · Parkinson's · diabetic neuropathy · ageing.
Reading the MCT report
- Latency in normal range, symmetric: intact reflex pathway — no central or peripheral slowing.
- Bilaterally prolonged latency: central CNS slowing (MS, Parkinson's, age-related decline) or proximal peripheral neuropathy.
- Asymmetric latency: focal lesion — stroke, focal demyelination, unilateral neuropathy.
- Abnormal amplitude: response too small (weakness) or too large (overshooting, often functional or anxiety-driven).
Reading the ADT report
- Decreasing sway across trials: normal cerebellar adaptation.
- Flat or variable sway: impaired motor learning — cerebellar degeneration, post-stroke cerebellum, ataxia.
- Toe-up vs toe-down asymmetry: direction-specific motor planning impairment, classically Parkinson's.