The Honest Palm Sign: Detecting Incomplete Effort on Physical Examination.

Background: We investigated a simple, novel diagnostic test for detecting incomplete effort during the motor portion of the neurological examination.

Methods: The results from the honest palm sign (HPS) were evaluated for 162 consecutive neuro-oncology patients who had undergone upper extremity strength testing. Deltoid, bicep, and wrist extensor strength was assessed in all patients. During the examination, patients were repeatedly encouraged to "try as hard as possible" and to "resist with all your strength." The absence of nail prints on the palms constituted a positive HPS test result (i.e., indicative of incomplete effort). The presence of nail prints constituted a negative HPS test result (i.e., indicative of full effort).

Results: A total of 162 patients were tested. Their mean age was 55.5 ± 14.9 years, the median Karnofsky performance scale score was 80 (range, 60-100), and 63 patients (39%) were men. Of the 162 patients, 102 (63%) had malignant gliomas, 28 (17%) had brain metastases, 21 (13%) had other primary brain tumors, and 11 (6.8%) had primary central nervous system lymphomas. Of the 162 patients, 48 (30%) had positive HPS test results. The test sensitivity (84.6%), specificity (75.2%), positive likelihood ratio (3.41), and negative likelihood ratio (0.205) were good. After excluding 33 patients with characteristics that rendered them unsuitable for testing, the results from the remaining 129 patients were analyzed. The sensitivity was unchanged (84.6%), but the specificity (96.6%), positive likelihood ratio (24.5), and negative likelihood ratio (0.16) improved dramatically.

Conclusions: The HPS test is a simple, sensitive, and very specific test for detecting incomplete effort during the motor portion of neurological evaluations.