Comments on van Veen et al's simplified nerve function tests.

In this paper in the March 2009 issue of Leprosy Review van Veen et al. presented an article on evaluating three simplified nerve function impairments (NFI) in leprosy. I have a question and a comment on this study. Question: In this multi-centric study in two countries, the authors decided to recruit at least 50 patients from each centre as samples; thus in 8 centres a total sample population of 408 were recruited. Under what assumption did the authors work out 400 as the sample size? Comment: General health workers (GHWs) are the ones who perform simplified NFI tests and the article mentions that the main objective of NFI is for diagnosis. In reality GHWs do not only diagnose but are also expected to monitor the ongoing therapy. Another very important job of theirs is to prevent secondary impairments. In our clinics, the hand foot injury ratio is 1:4 or even 1:5. The most common preventive management of secondary impairment in the lower limb is: selection/suggestion and often issue of proper footwear. For this GHWs have to depend on NFI results. For example, if a patient has sensory loss and the intrinsic muscle paralysis of the foot, the GHW has to suggest sandals (preferably MCR) with back strap. This requires NFI status of plantar intrinsic muscles. Interestingly none of the simplified NFI tests evaluated in this study addressed this aspect. The glaring defect was that the study’s gold standard test called ‘full assessment’ itself was incomplete and lacked this information! The paper grip test is a reliable and a simple test, which a GHW can easily learn and does not take more than 5 minutes to perform.