Functional gait disorders: A sign-based approach.

Functional gait disorders are common in clinical practice. They are also usually disabling for affected individuals. The diagnosis is challenging because no single walking pattern is pathognomonic for a functional gait disorder. Establishing a diagnosis is based not primarily on excluding organic gait disorders but instead predominantly on recognizing positive clinical features of functional gait disorders, such as an antalgic, a buckling, or a waddling gait. However, these features can resemble and overlap with organic gait disorders. It is therefore necessary to also look for inconsistency (variations in clinical presentation that cannot be reconciled with an organic lesion) and incongruity (combination of symptoms and signs that is not seen with organic lesions). Yet, these features also have potential pitfalls as inconsistency can occur in patients with dystonic gait or those with freezing of gait. Similarly, patients with dystonia or chorea can present with bizarre gait patterns that may falsely be interpreted as incongruity. A further complicating factor is that functional and organic gait disorders may coexist within the same patient. To improve the diagnostic process, we present a sign-based approach-supported by videos-that incorporates the diverse clinical spectrum of functional gait disorders. We identify 7 groups of supportive gait signs that can signal the presence of functional gait disorders. For each group of signs, we highlight how specific clinical tests can bring out the inconsistencies and incongruencies that further point to a functional gait disorder.