The Neuropad test: a visual indicator test for human diabetic neuropathy.

AIMS/HYPOTHESIS: The commercially available Neuropad test was developed as a simple visual indicator test to evaluate diabetic neuropathy. It uses a colour change to define the integrity of skin sympathetic cholinergic innervation. We compared the results of Neuropad assessment in the foot with established measures of somatic and autonomic neuropathy. METHODS: Fifty-seven diabetic patients underwent Neuropad assessment, quantitative sensory and autonomic function testing, and evaluation of intra-epidermal nerve fibre density in foot skin biopsies. RESULTS: Neuropad responses correlated with the neuropathy disability score (r(s)=0.450, p<0.001), neuropathic symptom score (r(s)=0.288, p=0.03), cold detection threshold (r(s)=0.394, p = 0.003), heat-as-pain perception threshold visual analogue score 0.5 (r(s)=0.279, p=0.043) and deep-breathing heart rate variability (r(s)= -0.525, p<0.001). Intra-epidermal nerve fibre density (fibres/mm) compared with age- and sex-matched control subjects (11.06+/-0.82) was non-significantly reduced (7.37+/-0.93) in diabetic patients with a normal Neuropad response and significantly reduced in patients with a patchy (5.01+/-0.93) or absent (5.02+/-0.77) response (p=0.02). The sensitivity of an abnormal Neuropad response in detecting clinical neuropathy (neuropathy disability score >or=5) was 85% (negative predictive value 71%) and the specificity was 45% (positive predictive value 69%). CONCLUSIONS/INTERPRETATION: The Neuropad test may be a simple indicator for screening patients with diabetic neuropathy.

Small fiber neuropathy in diabetes: clinical consequence and assessment.

Recent findings have shed new light on the role of peripheral nerves in the skin and have established a modern concept of cutaneous neurobiology. There is bidirectional rather than unidirectional (conveying information from the periphery) signaling between central and peripheral nerves and the endocrine and immune systems. This interaction is mediated principally by cutaneous small nerve fibers and will influence a variety of physiologic and pathophysiologic functions central to wound healing, which include cellular development, growth, differentiation, immunity, vasoregulation, and leukocyte recruitment. Thus, disease of the small fibers in diabetic patients is frequent and may have a considerable impact on the predisposition and subsequent wound-healing response to foot ulceration. The authors review the basic pathophysiology, clinical consequences, and current methods to evaluate somatic and autonomic nerve fiber dysfunction and damage.

The organization of rapid eye movement activity during rapid eye movement sleep is impaired in the elderly.

Rapid eye movement activity (REMA) during rapid eye movement activity (REM) sleep was studied in eight elderly subjects and six young adults as a control group. Beyond global quantitative features (REMA density), we evaluated the organizational aspects of REMA, that is its occurrence in burst mode, still largely unknown in the aged. REMA density in the elderly is not significantly different than that of young adults. By contrast, the duration of REMA bursts is reduced in the elderly, as well as the 'burst state-to-burst-state' probability, i.e. the probability for successive inter-REMA time intervals to be part of the same REMA burst. These results show that global aspects of the quantitative features of REMA are preserved in the elderly, whereas their organizational aspects are impaired. These data are consistent with the hypothesis that aging is associated with a difficulty in maintaining physiological processes over time.