Hoovers Sign (Neurological)

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Purpose[edit | edit source]

The purpose of the test is to differentiate between leg paresis that has no definitive neurological pathology (non-organic) to that which has a definite, identifiable cause (organic)[1]. This test was first described by Dr Charles Franklin Hoover in 1908 as a bedside test to identify functional weakness in the lower extremities[2], and is 1 of 2 tests ascribed to him, the other being Hoover's Sign (Pulmonary).

Technique[edit | edit source]

Hoover's sign is a motor sign. It is based on the principle of crossed extensor reflex - when one hip is flexed, the contralateral hip is extended[3], eg. if a person in supine is asked to lift the right leg up with knee extended, the left heel will be observed to dig into the plinth[4].

Hoover's sign examines the inconsistency between automatic hip extension vs voluntary hip extension - hip extension in a patient with unilateral functional weakness is weak when tested directly, but briefly returns to normal when triggered by contralateral hip flexion[5].

The patient is placed in a supine/recumbent position. The examiner places his/her hand under the patient's heel. The patient is then instructed to press the heels down onto the table. The examiner is expected to feel pressure on the non-paretic limb. The patient is then asked to raise his/her non-paretic limb against downward resistance applied by the therapist. No pressure is expected to be felt under the paretic leg that is on the table[1]. The Hoover's sign is when pressure is felt under the paretic leg when the non-paretic leg is raised and no pressure is felt in the non-paretic leg when the paretic leg is being raised[6].

 [7]
 [8]

Discussion[edit | edit source]

It should be noted that apraxia, a common neurological deficit, could also explain failure to voluntarily extend the hip[9].

Contralateral Knee Sign[edit | edit source]

The contralateral knee sign is a new test proposed as an extension of the Hoover's sign, based on the same principles governing it: the crossed extensor reflex. This test aims to unveil functional paralysis of knee extension by testing for automatic knee extension[10].

Technique[10][edit | edit source]

With the patient in supine, the therapist first evaluates the strength of the quadriceps by placing one hand under the knee of the weak leg and asking the patient to exert downward pressure. Keeping the hand under the patient's knee, ask the patient to raise the contralateral, unaffected limb against resistance. Contralateral hip and knee flexion leads to an involuntary knee extension, reflected as a downward pressure against the examiner's hand. If this pressure is stronger than previously exerted, the test is considered positive. The discrepancy between voluntary extension and automatic knee extension supports a diagnosis of functional paralysis of knee extension.

Sensitivity: 83%, Specificity: 93% (78% to 99%). Although it should be noted this is based on a very small sample of 30 patients.

Evidence[edit | edit source]

Sensitivity 63% [11][12]

specificity 100%[11][12]

Hoover's sign was moderately sensitive and very specific for a diagnosis of functional weakness.[11]

References[edit | edit source]

  1. Koehler, P.J., Okun, M.S. (2004). Important observations prior to the description of the Hoover sign.  Historical Neurology. 63: 1693-1697.
  2. Larner, A.J. (2001). A Dictionary of Neurological signs. Springer.
  1. ↑ 1.0 1.1 Ziv, I., Djaldetti, R., Zoldan, J., Avraham, M., Melamed, E. (1998). Diagnosis of "non-organic" limb paresis by a novel objective motor assessment: The quantitative Hoover's test. Journal of Neurology, 245: 797-802.
  2. ↑ Shams T, Ashraf F, DeGeorgia M. Charles Franklin Hoover and the Hoover Sign (P04. 006). Neurology Apr 2012 78:1
  3. ↑ 1. Koehler PJ, Okun MS. Important observations prior to the description of the Hoover sign. Neurology. 2004;63(9):1693–7.
  4. ↑ Hoover CF. A NEW SIGN FOR THE DETECTION OF MALINGERING AND FUNCTIONAL PARESIS OF THE LOWER EXTREMITIES. Journal of the American Medical Association. 1908;LI(9):746–7.  
  5. ↑ Cock HR, Edwards MJ. Functional neurological disorders: acute presentations and management. Clin Med (Lond). 2018 Oct;18(5):414-417. doi: 10.7861/clinmedicine.18-5-414. PMID: 30287439; PMCID: PMC6334101.
  6. ↑ Kaufman, D.M. (2007). Clinical neurology for psychiatrists: 6th edition. Elsevier Health Sciences. p. 20.
  7. ↑ online video, http://www.youtube.com/watch?v=F4Fk_ZzCX6A, last accessed 6/2/2009
  8. ↑ Clinically Relevant Technologies, http://www.youtube.com/watch?v=QqQuPL36loM, last accessed May 2011
  9. ↑ Ercoli T, Stone J. False Positive Hoover's Sign in Apraxia. Movement disorders clinical practice (Hoboken, NJ). 2020;7(5):567–8.  
  10. ↑ 10.0 10.1 Brigo F. Contralateral knee sign: an extension of the Hoover's sign to unveil functional paralysis of knee extension. Neurological sciences. 2023;44(9):3351–2.
  11. ↑ 11.0 11.1 11.2 McWhirter, Laura, et al. "Hoover's sign for the diagnosis of functional weakness: a prospective unblinded cohort study in patients with suspected stroke." Journal of psychosomatic research 71.6 (2011): 384-386.
  12. ↑ 12.0 12.1 Mehndiratta MM, Kumar M, Nayak R, Garg H, Pandey S. Hoover's sign: Clinical relevance in Neurology. J Postgrad Med. 2014;60(3):297-299. doi:10.4103/0022-3859.138769
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