An examiner passively moves a patient's arm into an unusual position and feels a smooth, even, wax-like resistance throughout the entire movement; once positioned, the arm remains there for several minutes, with the patient not appearing to actively resist at any point. Before revealing the answer: is this perseveration of posture?
No, this is more consistent with waxy flexibility than perseveration of posture. The smooth, continuous resistance felt throughout the passive movement itself is the defining feature of waxy flexibility, whereas perseveration of posture specifically involves no resistance during the movement, with active contraction felt only at the moment of release.
References
- Casey, P. & Kelly, B. (2019). Fish's Clinical Psychopathology, 4th ed. Ch. 8, 'Motor Disorders'.