Neurological examination of the upper limb: a study of construct validity

Abstract

Objective: We have previously demonstrated that neurological individual findings and patterns can be reliably assessed in the examination of the upper limb and also that they are related to pain, weakness, and/or numbness/tingling. This study aimed to study further aspects of the construct validity of the neurological examination.

Methods: Blinded to patient-characteristics, two examiners assessed the function of 16 muscles, the sensibility in 7 territories, and the nerve-mechanosensitivity at 20 locations in 82 upper limbs. Based on anatomical patterns and pre-designed algorithms, one or both examiners rated neuropathy as "possible" or "definite" in 40 limbs and also determined the location( s). We developed and tested hypotheses on anatomically and regionally related locations of nerve afflictions (a selective vulnerability of neurons, double and multiple crush, and a tendency to regional spread) and examined the stability of the internal structure of the constructs in different situations. The interrelations of findings were analyzed by hypothesis testing and factor analyses, and the homogeneity of location profiles was analyzed by a conditional likelihood test.

Results: Out of 30 limbs with related locations of neuropathy, the findings of each examiner correlated positively (gamma > 0.35) in 22/25, respectively. The patterns of the interrelations identified by the two examiners were similar, with no evidence of any heterogeneity of location profiles for either examiner.

Conclusions: This study supports the validity of the physical examination. However, feasibility of its application requires the demonstration of further aspects of construct validity and a favorable influence on patient-management and/or prevention.

Keywords: Upper limb physical examination; conditional likelihood test.; construct validity; factor analyses; hypothesis testing.

Fig. (1). Examined locations of neuropathy along the course of upper limb nerves.

Circles represent locations for neuropathy. A: Supraclavicular brachial plexus (scalene triangle), B: Clavicular brachial plexus, C: Infraclavicular brachial plexus (minor pectoral muscle), E: Suprascapular nerve (suprascapular notch), D: Axillary nerve (quadrilateral space), F: Musculocutaneous nerve (passage through coracobrachial muscle), G: Radial nerve (triceps arcade, brachioradial arcade, passage over radiohumeral joint), H: Radial nerve (arcade of Frohse), I: Median nerve (medial aspect of upper arm, lacertus fibrosus, pronator teres muscle, arcade of superficial flexor muscle), J: Median nerve (carpal tunnel), K: Ulnar nerve (arcade of Struther, medial head of triceps muscle, sulcus of ulnar nerve, aponeurosis of ulnar flexor of wrist), L: Ulnar nerve (canal of Guyon). Lines represent the inter-correlations studied by hypothesis testing of conditional correlations.