The upgoing thumb sign: An interobserver/intraobserver reliability study

Area of Science:

• Neurology
• Clinical Neuroscience

Background:

• The upgoing thumb sign is a subtle clinical finding associated with upper motor neuron involvement.
• It has been frequently reported in patients experiencing transient ischemic attacks (TIAs) and minor strokes.

Purpose of the Study:

• To demonstrate the examination method and interpretation of the upgoing thumb sign.
• To assess the interobserver and intraobserver reliability of this neurological finding.

Main Methods:

• The thumb sign was elicited in patients with TIAs, minor strokes, or stroke mimics.
• Examinations were recorded, and two neurologists independently reviewed them.
• After training, a group of healthcare professionals reviewed videos and rated the thumb sign, with intraobserver reliability assessed after 3 months.

Main Results:

• Interobserver reliability among 9 raters showed substantial agreement (overall agreement 0.83, kappa 0.66).
• Intraobserver reliability was also substantial to almost perfect (mean kappa 0.86) when assessed after 3 months.

Conclusions:

• The upgoing thumb sign is a reliable neurological finding for upper limb assessment.
• The test is simple to perform and accurately interpreted, with high interobserver and intraobserver reliability.