Diagnostic accuracy of the neurological upper limb examination I: inter-rater reproducibility of selected findings and patterns

Abstract

Background: We have previously assessed the reproducibility of manual testing of the strength in 14 individual upper limb muscles in patients with or without upper limb complaints. This investigation aimed at additionally studying sensory disturbances, the mechanosensitivity of nerve trunks, and the occurrence of physical findings in patterns which may potentially reflect a peripheral neuropathy. The reproducibility of this part of the neurological examination has never been reported.

Methods: Two blinded examiners performed a semi-quantitative assessment of 82 upper limbs (strength in 14 individual muscles, sensibility in 7 homonymous territories, and mechanosensitivity of nerves at 10 locations). Based on the topography of nerves and their muscular and cutaneous innervation we defined 10 neurological patterns each suggesting a focal neuropathy. The individual findings and patterns identified by the two examiners were compared.

Results: Strength, sensibility to touch, pain and vibration, and mechanosensitivity were predominantly assessed with moderate to very good reproducibility (median kappa-values 0.54, 0.69, 0.48, 0.58, and 0.53, respectively). The reproducibility of the defined patterns was fair to excellent (median correlation coefficient = 0.75) and the overall identification of limbs with/without pattern(s) was good (kappa = 0.75).

Conclusion: This first part of a study on diagnostic accuracy of a selective neurological examination has demonstrated a promising inter-rater reproducibility of individual neurological items and patterns. Generalization and clinical feasibility require further documentation: 1) Reproducibility in cohorts of other composition, 2) validity with comparison to currently applied standards, and 3) potential benefits that can be attained by the examination.

Figure 1

Flow diagram illustrating the patient sample and the main findings.

Figure 2

Distribution of 14 upper limb muscles in relation to the cervical roots.

Figure 3

Pattern of muscle weakness with upper trunk involvement. Pareses of Infraspinatus, Deltoid and Biceps muscles. Note: The FCR muscle should always be found normal with an isolated upper trunk involvement

Figure 4

The position of the nerves to selected muscles within the infraclavicular brachial plexus and the patterns of muscle weakness with an infraclavicular plexus involvement. The involvement may be limited to its lateral part only (pareses of Deltoid, Biceps and FCR muscles), also include its intermediate part (in addition pareses of Latissimus, Triceps and ECRB muscles), or even its medial part (in addition to all the previous, pareses of Pectoral and ADM muscles). Note: The Infraspinatus muscle is normal with an isolated infraclavicular plexus involvement. For abbreviations see Table 2

Figure 5

Pattern of muscle weakness with medial nerve involvement. Involvement at the elbow level, pronator syndrome causes pareses of FCR and FPL muscles. Involvement at the wrist level, carpal tunnel syndrome, causes paresis of the APB muscle. For abbreviations see Table 2

Figure 6

Pattern of muscle weakness with radial and interosseous nerve involvement. Radial nerve involvement at the upper arm level causes pareses of Triceps, ECRB and EPL muscles. Posterior interosseous nerve involvement at the level of the Supinator muscle, arcade of Frohse, radial tunnel syndrome causes paresis of the ECU muscle. For abbreviations see Table 2.

Figure 7

Pattern of muscle weakness with ulnar nerve involvement. Ulnar nerve involvement at the elbow level, cubital tunnel syndrome causes pareses of FDP V and ADM muscles, and at the wrist level, Guyon's canal, paresis of the ADM muscle. For abbreviations see Table 2