REFERENCE · DIAGNOSTIC TECHNIQUES

Functional Paralysis Diagnostic Inventory

All nine original descriptions and source associations are preserved. These include signs, observations, investigations and applicability cautions; they are not nine universally validated tests. No new entry is added.

Home › Diagnostic Signs › Paralysis overview › Inventory

Detailed guides

Original nine entries

Automatic heel pressure may be preserved during movement of the other leg despite absent requested movement. This comparison can support functional weakness when the opposite leg is sufficiently strong. It cannot be assumed valid in severe bilateral paralysis. [2]

Hip-abductor sign

The clinician compares sideways leg force during paired and separate tasks. Preserved associated force may support a functional component in a suitable asymmetric presentation. The primary study was small and unblinded; pain and limitations in the comparison leg matter. [4]

Abduction-finger sign

Resisted spreading of fingers in the less affected hand may produce associated spreading in the paralysed hand. The original severe-unilateral-paralysis study supports this sign. Extrapolation to partial weakness is unsafe because associated movements also occur without functional paralysis. [3]

Spinal Injuries Center test

A severely weak leg may maintain a bent-knee position after being placed there, despite inability to lift voluntarily. A primary comparative study supports this restricted use. Milder neurological weakness can also maintain the position, and mechanical support must be considered. [5]

Elbow flex-ex comparison

Opposite-direction force may emerge in the weak arm during resisted movement of the other arm. The original unilateral-weakness study supports a possible functional contrast, but evidence is small and does not establish a universal test for complete bilateral paralysis. [6]

Preserved automatic or task-linked movement

A clinician may observe movement during a comfortable repositioning or another spontaneous action that is unavailable on request. This can provide positive evidence only when the comparison truly tests the same capacity and excludes compensation or reflex movement. [7][8]

Tone, reflexes and plantar responses

These help localize disease and interpret the paralysis. An older comparative series described preserved findings, but normal tone or reflexes alone do not establish FND and may occur in other disorders. Historical psychiatric or compensation-based assumptions are not diagnostic signs. [9]

Motor and sensory pathway investigations

Selected nerve-conduction, EMG, evoked-potential or imaging studies investigate competing and coexisting disease. They are not positive FND tests. Normal findings do not establish the cause of paralysis or rule out every neurological condition. [10]

Tests that require residual voluntary movement

Drift without pronation, collapsing weakness and paradoxical wrist flexion require movement or force that may be absent in complete paralysis. Inability to perform them is not a positive result. Use the limb-weakness page only when the phenotype fits. [11][12]

Research and Sources

Original local citation numbers are retained. Historical terminology remains only where needed for source identification; it does not establish intention, motive or cause.

Citation	Figure	Full citation
[1]	—	Bennett K, Diamond C, Hoeritzauer I, Gardiner P, McWhirter L, Carson A, Stone J. A practical review of functional neurological disorder (FND) for the general physician. Clinical Medicine. 2021;21(1):28–36. FND-CIT-0001. https://doi.org/10.7861/clinmed.2020-0987
[2]	—	McWhirter L, Stone J, Sandercock P, Whiteley W. Hoover’s sign for the diagnosis of functional weakness: a prospective unblinded cohort study in patients with suspected stroke. Journal of Psychosomatic Research. 2011;71(6):384–386. FND-CIT-0018. https://doi.org/10.1016/j.jpsychores.2011.09.003
[3]	—	Tinazzi M, Simonetto S, Franco L, et al. Abduction finger sign: a new sign to detect unilateral functional paralysis of the upper limb. Movement Disorders. 2008;23(16):2415–2419. FND-CIT-0057. https://doi.org/10.1002/mds.22268
[4]	—	Sonoo M. Abductor sign: a reliable new sign to detect unilateral non-organic paresis of the lower limb. Journal of Neurology, Neurosurgery & Psychiatry. 2004;75(1):121–125. Historical terminology retained in the article title. FND-CIT-0058. https://pmc.ncbi.nlm.nih.gov/articles/PMC1757483/
[5]	—	Yugué I, Shiba K, Ueta T, Iwamoto Y. A new clinical evaluation for hysterical paralysis. Spine. 2004;29(17):1910-3; discussion 1913. DOI. PMID: 15534415. FND-CIT-0166.
[6]	—	Lombardi TL, Barton E, Wang J, et al. The elbow flex-ex: a new sign to detect unilateral upper extremity non-organic paresis. Journal of neurology, neurosurgery, and psychiatry. 2014;85(2):165-167. DOI. PMID: 23695497. FND-CIT-0134.
[7]	—	Stone J, Warlow C, Sharpe M. The symptom of functional weakness: a controlled study of 107 patients. Brain : a journal of neurology. 2010;133(Pt 5):1537-1551. DOI. PMID: 20395262. FND-CIT-0047.
[8]	—	Daum C, Gheorghita F, Spatola M, et al. Interobserver agreement and validity of bedside ‘positive signs’ for functional weakness, sensory and gait disorders in conversion disorder: a pilot study. Journal of neurology, neurosurgery, and psychiatry. 2015;86(4):425-430. DOI. PMID: 24994927. FND-CIT-0130.
[9]	—	Baker JH, Silver JR. Hysterical paraplegia. Journal of neurology, neurosurgery, and psychiatry. 1987;50(4):375-382. DOI. PMID: 3585346. FND-CIT-0120.
[10]	—	Edwards MJ, Koens LH, Liepert J, et al. Clinical neurophysiology of functional motor disorders: IFCN Handbook Chapter. Clinical neurophysiology practice. 2024;9:69-77. DOI. PMID: 38352251. FND-CIT-0022.
[11]	—	Daum C, Aybek S. Validity of the “Drift without pronation” sign in conversion disorder. BMC neurology. 2013;13:31. DOI. PMID: 23548051. FND-CIT-0131.
[12]	—	Sonoo M. Paradoxical wrist flexion: A new test to detect functional weakness of the upper limb. eNeurologicalSci. 2021;22:100302. DOI. PMID: 33344786. FND-CIT-0185.

Continue: Functional Drop Attacks

Navigate: Home · Course · Reference Library · Site Map