Functional gait disorders are recognized by internal inconsistency and by movements that are uneconomic. The near-fall that is always corrected demonstrates that the postural and motor systems needed to prevent the fall are working normally, and often working harder than normal walking would require. This is the truncal ataxia or astasia-abasia pattern, in which wide sway with excellent recovery, and expenditure of far more muscular energy than efficient walking would need, indicates that balance mechanisms are intact.
The classic video study of psychogenic stance and gait identified six features present alone or in combination in 97 percent of patients: momentary fluctuation often in response to suggestion, excessive slowness or hesitation incompatible with disease, a psychogenic Romberg with build-up of sway after a silent latency or improvement on distraction, uneconomic posture with wastage of muscular energy, a walking-on-ice pattern with small cautious steps and fixed ankles, and sudden knee buckling usually without falls. Other well recognized patterns include the dragging monoplegic gait and excessive slowness.
Recognizing a functional gait at a glance is expected of every resident, so this item sits at the Core level of RITE content. Watching the patient walk in and out of the room, and while distracted by conversation, is often more informative than the formal gait examination.
Incorrect Answers
- A. A wide base with impaired tandem gait is a nonspecific finding common in cerebellar disease, sensory ataxia and normal elderly gait.
- B. Small hesitant steps alone occur in cautious gait, frontal gait disorder and parkinsonism, and do not by themselves indicate a functional cause.
- C. Knee buckling is one of the six suggestive features but occurs in isolation in quadriceps weakness and in patellofemoral pain, so it is weaker evidence than uneconomic sway with preserved recovery.
- D. An abducted arm posture is a normal compensatory strategy in many genuine balance disorders.
Testing Pearls
- Uneconomic gait with excellent balance recovery is a strong positive sign of functional gait.
- The six Lempert features are present alone or combined in 97 percent of psychogenic gait disorders.
- The walking-on-ice pattern shows small cautious steps with fixed ankle joints.
- A psychogenic Romberg shows sway building after a latency and improving with distraction.
- Observe walking on arrival and during distraction, not only during formal testing.
References
- Jankovic J, Mazziotta JC, Newman NJ, Pomeroy SL, editors. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022. p. 2083.
- Lempert T, Brandt T, Dieterich M, Huppert D. How to identify psychogenic disorders of stance and gait. A video study in 37 patients. J Neurol. 1991;238(3):140-146.
- Daum C, Hubschmid M, Aybek S. The value of "positive" clinical signs for weakness, sensory and gait disorders in conversion disorder: a systematic and narrative review. J Neurol Neurosurg Psychiatry. 2014;85(2):180-190.
