The sensitivity and specificity of the neurological examination in polyneuropathy patients with clinical and electrophysiological correlations

Abstract

IntroductionPolyneuropathy is one of the most prevalent neurologic disorders. Although several studies explored the role of the neurological examination in polyneuropathy, they were mostly restricted to specific subgroups of patients and have not correlated examination findings with symptoms and electrophysiological results.ObjectivesTo explore the sensitivity and specificity of different neurological examination components in patients with diverse etiologies for polyneuropathy, find the most sensitive combination of examination components for polyneuropathy detection, and correlate examination findings with symptoms and electrophysiological results.MethodsPatients with polyneuropathy attending the neuromuscular clinic from 01/2013 to 09/2015 were evaluated. Inclusion criteria included symptomatic polyneuropathy, which was confirmed by electrophysiological studies. 47 subjects with no symptoms or electrophysiological findings suggestive for polyneuropathy, served as controls.ResultsThe total cohort included 312 polyneuropathy patients, with a mean age of 60±14 years. Abnormal examination was found in 95%, most commonly sensory findings (86%). The most common abnormal examination components were impaired ankle reflexes (74%), vibration (73%), and pinprick (72%) sensation. Combining ankle reflex examination with vibration or pinprick perception had the highest sensitivity, of 88%. The specificities of individual examination component were generally high, excluding ankle reflexes (62%), and vibration perception (77%). Abnormal examination findings were correlated with symptomatic weakness and worse electrophysiological parameters.ConclusionThe neurological examination is a valid, sensitive and specific tool for diagnosing polyneuropathy, and findings correlate with polyneuropathy severity. Ankle reflex examination combined with either vibration or pinprick sensory testing is the most sensitive combination for diagnosing polyneuropathy, and should be considered minimal essential components of the physical examination in patients with suspected polyneuropathy.

Toronto Clinical Neuropathy Score is valid for a wide spectrum of polyneuropathies

“…The current study shows that the usefulness of the TCNS extends beyond diabetic polyneuropathy, based on correlations of the TCNS with clinical, electrophysiological and disability parameters in non-diabetic polyneuropathies, and excellent reliability and accuracy. Moreover, the correlation of the sural SNAP with the TCNS was higher than correlations with individual components of the neurological examination [2] or with other neuropathy scales studied in patients with impaired glucose tolerance and polyneuropathy [4]. This observation is probably related to the relative weighting of the TCNS with sensory symptoms and examination.…”

The utility of a single simple question in the evaluation of patients with nondiabetic polyneuropathy

“…However, the TCNS has the advantage of correlating with electrophysiological measures, in contrast to the “percentage of normal.” The correlations of the TCNS with electrophysiological findings may stem from its structure, which integrates sensory and motor symptoms, as well as assessment of objective sensory deficits and the presence of decreased or absent reflexes. Although neurological examination signs are correlated with electrophysiological measures, they may not be reflected by patient's sense of well‐being, as expressed by the “percentage of normal” question. Possible explanations for lower correlation between symptoms and electrophysiological findings in polyneuropathy may include the lack of significant correlation between pain and the degree of axonal loss, and reinnervation that leads to underestimation of the true degree of axonal loss in polyneuropathies.…”

“…Although neurological examination signs are correlated with electrophysiological measures, they may not be reflected by patient's sense of well‐being, as expressed by the “percentage of normal” question. Possible explanations for lower correlation between symptoms and electrophysiological findings in polyneuropathy may include the lack of significant correlation between pain and the degree of axonal loss, and reinnervation that leads to underestimation of the true degree of axonal loss in polyneuropathies. The weak correlation found between grip strength and both “percentage of normal” and TCNS was expected, considering the length‐dependent nature of most polyneuropathies, affecting predominantly the lower limbs.…”

“…Although this study has included a wide spectrum of polyneuropathies, it did not include polyneuropathies secondary to diabetes, which is the most frequent etiology for polyneuropathy . However, as there is significant phenotypic similarity between various types of polyneuropathy, study results are most likely applicable also for diabetic and other types of polyneuropathy.…”

“…Although this study has included a wide spectrum of polyneuropathies, it did not include polyneuropathies secondary to diabetes, which is the most frequent etiology for polyneuropathy. 12 However, as there is significant phenotypic similarity between various types of polyneuropathy, study results are most likely applicable also for diabetic and other types of polyneuropathy. In addition, we have not explored the responsiveness of the question, in order to determine its role for monitoring changes over time in polyneuropathy severity, although changes in "percentage of normal" did show strong correlation with change in the quantitative myasthenia gravis score.…”