Functional Limb Weakness: Diagnostic Inventory

Automatically generated inventory. Sixteen baseline entries retained; summaries other than Hoover’s sign have not received a new full-text review in this expansion. These are not sixteen independently validated tests.

Diagnostic techniques at a glance

These brief entries describe signs, observations, criteria and investigations clinicians may consider. They are not a checklist of tests everyone needs. Evidence and limitations differ for each entry; a positive sign must fit the whole clinical picture, including possible coexisting disease.

Hoover’s sign now has a detailed page. Other entries remain the baseline summaries pending individual expansion and evidence review.

Hoover’s sign

Read the detailed assessment.

The clinician compares requested heel pressure with automatic pressure during the opposite leg’s movement. A clear contrast supports functional leg weakness. Prospective accuracy evidence includes only a small functional subgroup; pain, neglect and bilateral weakness can confound it. [2][3]

Hip-abductor sign

Hip abduction means moving the leg sideways. The clinician compares this force during separate and paired leg tasks. Stronger automatic force on the weak side may support FND. The original small study was unblinded; painful hips and difficulty following instructions limit interpretation. [4]

Drift without pronation

With the arms held forward and palms up, one arm drifts down without turning inward. This supports a functional pattern in some partial arm weakness. The original study was small and unblinded; complete paralysis was excluded, and false positives occurred. [5][6]

Paradoxical wrist flexion

The clinician compares wrist-bending strength in two defined positions. Greater strength in the position normally expected to be weaker is the positive contrast. A retrospective study supports this sign in mild weakness; wrist pain, surgery and different testing positions limit its use. [7]

Elbow flex-ex sign

Resistance against movement of the less affected arm may bring out opposite-direction force in the weak arm. That contrast can support functional arm weakness. The original study included only ten functional cases and used unblinded examination. Name this specific arm sign rather than labelling it Hoover’s sign. [8]

Give-way or collapsing weakness

During strength examination, resistance stops abruptly rather than gradually yielding. This can contribute to a functional formulation, but pain, fatigue, comprehension and other disorders can affect performance. It is not a sufficient diagnosis or a measure of honesty. [3][6][9]

Make-versus-break dynamometry

A hand-held force meter compares pushing against a fixed examiner with resisting movement imposed by the examiner. Disproportionately greater force in the second condition was studied as a functional contrast. Small-study results depend on the exact protocol; ordinary strength variation is insufficient. [10]

Task-related motor inconsistency

The clinician compares the same movement capacity across direct testing and ordinary, supported activities. A specific, reproducible discrepancy may contribute to diagnosis. Changing pain, compensation and task demands need explanation; simply moving better on another occasion is not proof. [3][6][9]

Quantitative Hoover testing

Force sensors measure the relationship between requested and associated leg movements. This is an instrumented comparison with primary research support, rather than a routine extra bedside sign. It cannot make findings from unsuitable patients or altered protocols reliable. [11]

Isokinetic strength testing

A machine measures knee force at controlled movement speeds. Inconsistent force across repeated trials or an unusual speed–force relationship were reported in an older study. This remains a specialist assessment with limited validation, not a requirement for diagnosis. [12]

Antagonist co-contraction

The clinician or EMG recording finds opposing muscles activating while a movement is requested. This may help explain a particular examination discrepancy, but guarding, pain and dystonia also cause co-contraction. Older dynamometry research does not validate every bedside version. [12]

Sternocleidomastoid sign

The clinician checks neck rotation and flexion for a pattern inconsistent with the limb examination. A controlled study supports this as an additional axial sign. Neck pain and other causes need assessment; this does not directly test the weak arm or leg. [13]

Platysma comparison

The clinician observes contraction of the thin neck muscle during an appropriate facial task. In the primary study, reduced contraction was an indicator of neurological weakness, while its absence could complement other functional findings. A normal result alone does not establish FND. [13]

Abduction-finger sign

Spreading the less affected hand against resistance may produce associated finger spreading in a paralysed hand. The primary study concerns severe unilateral paralysis; ordinary mirror movements make extrapolation to partial weakness unsafe. See the paralysis page for the matching presentation. [14]

Spinal Injuries Center test

A leg unable to lift voluntarily may maintain a supported bent-knee position once placed there. The original study concerns severe leg weakness or paralysis; milder neurological weakness can produce the same observation. Use the paralysis page for its proper scope. [15]

Arm/hand-drop avoidance: not a validated weakness sign

Face avoidance during arm release has appeared in clinical descriptions, including assessment of apparent unresponsiveness. These publications do not establish it as a validated arm-weakness test. Never drop a limb toward the face; see the seizure page for the separate unresponsiveness observation. [16][17]

Evidence map: The 2025 review helps locate the original weakness studies; those primary papers are cited separately above. Its search ended in March 2024, so it cannot establish that later replication literature is complete. [18]

Research and Sources

Citation	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]	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.
[4]	Sonoo M. Abductor sign: a reliable new sign to detect unilateral non-organic paresis of the lower limb. Journal of neurology, neurosurgery, and psychiatry. 2004;75(1):121-125. PMID: 14707320. FND-CIT-0058.
[5]	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.
[6]	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.
[7]	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.
[8]	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.
[9]	Chabrol H, Peresson G, Clanet M. Lack of specificity of the traditional criteria for conversion disorders. European psychiatry : the journal of the Association of European Psychiatrists. 1995;10(6):317-319. DOI. PMID: 19698360. FND-CIT-0126.
[10]	van der Ploeg RJ, Oosterhuis HJ. The “make/break test” as a diagnostic tool in functional weakness. Journal of neurology, neurosurgery, and psychiatry. 1991;54(3):248-251. DOI. PMID: 2030354. FND-CIT-0152.
[11]	Ziv I, Djaldetti R, Zoldan Y, et al. Diagnosis of “non-organic” limb paresis by a novel objective motor assessment: the quantitative Hoover’s test. Journal of neurology. 1998;245(12):797-802. DOI. PMID: 9840352. FND-CIT-0162.
[12]	Knutsson E, Mårtensson A. Isokinetic measurements of muscle strength in hysterical paresis. Electroencephalography and clinical neurophysiology. 1985;61(5):370-374. DOI. PMID: 2412788. FND-CIT-0150.
[13]	Horn D, Galli S, Berney A, et al. Testing Head Rotation and Flexion Is Useful in Functional Limb Weakness. Movement disorders clinical practice. 2017;4(4):597-602. DOI. PMID: 30363481. FND-CIT-0155.
[14]	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 : official journal of the Movement Disorder Society. 2008;23(16):2415-2419. DOI. PMID: 18951441. FND-CIT-0057.
[15]	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.
[16]	Marcus H, Aldam P, Lennox G, Laing R. Medically unexplained neurological symptoms. JRSM short reports. 2010;1(3):25. DOI. PMID: 21103117. FND-CIT-0153.
[17]	Bacchi S, Slee M. Physical examination in functional unresponsiveness. Practical neurology. 2023;23(1):54-56. DOI. PMID: 36717206. FND-CIT-0119.
[18]	Dolbow J, El-Azzouni S, Zhang Y, Geiger C. A practical guide to assessing functional motor weakness: a review of validated techniques. Journal of neurology. 2025;272(6):427. DOI. PMID: 40423819. FND-CIT-0183.