Neurology -- Correspondence for Sharief et al., 59 (10) 1518-1525

Correspondence published:

Neurophysiologic analysis of neuromuscular symptoms in UK Gulf War veterans: A controlled study: Vance A Spence (9 September 2003)

Reply to Letter to the Editor: Michael R Rose (9 September 2003)

Neurophysiologic analysis of neuromuscular symptoms in UK Gulf War veterans: A controlled study 9 September 2003

Vance A Spence,
Ninewells Hospital & Medical School University of Dundee
Department of Medicine Vascular Diseases Research Unit Dundee DD1 9SY Scotland, United Kingdom
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Re: Neurophysiologic analysis of neuromuscular symptoms in UK Gulf War veterans: A controlled study

vance.spence{at}ntlworld.com Vance A Spence

In the paper on neurophsyiological symptoms in Gulf War veterans, Sharief et al. provide specific information on the selection criteria for subjects. [1] Symptomatic servicemen were randomly selected and recruited to the study on the basis that they had scored at least four neuromuscular symptoms (from fatigue, joint stiffness, muscle weakness, myalgia at rest and after exercise, sensory symptoms, and autonomic symptoms), and had, in addition, an SF-36 score of <72.2. To understand how the figure of <72.2 was estimated readers are referred to an accompanying reference [2], but an examination of that reference does not reveal how this figure was derived. It is important to have this information, however, since the selection criteria used to define entry into the study are critical to the study’s conclusions. It is also important for comparison with the recruitment criteria used in other, similar studies.
Since this it is a matter of importance for our current research in the Vascular Research Unit at the University of Dundee on Gulf War Syndrome and related conditions, it would be very helpful if the authors could explain in your correspondence section how this critical SF-36 score of <72.2, used to select subjects, was calculated in their investigation.
References:
1. Sharief MK, Priddin J, Delamont RS, Unwin C, Rose MR, David A, Wessley S. Neurophysiologic analysis of neuromuscular symptoms in UK Gulf War veterans. Neurology 2002;59:1518-1525.
2. Unwin C, Blatchley N, Coker W et al. Is there a Gulf War syndrome? Lancet 1999;353:179-182.

Reply to Letter to the Editor 9 September 2003

Michael R Rose,
King's College Hospital
Department of Neurology King's Neurosciences Centre Denmark Hill London, SE5 9RS United Kingdom
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Re: Reply to Letter to the Editor

m.r.rose{at}kcl.ac.uk Michael R Rose

We thank Dr. Spence for drawing our attention to the fact that we have inadvertently cited an incorrect reference in our paper. [1, 2] The correct reference is Ismail et al. from 2002. [3] For the convenience of readers the relevant extract from that paper is as follows;
In the absence of a clear definition of Gulf related ill health, we used a generic measure of physical disability, the Short-Form 36 Physical Functioning subscale (SF-36 PF), which was measured at Phase 1 as our proxy measure for ill health. The value of the first decile of the distribution of the SF-36 PF in the Era cohort (score =72.2) was used as the cut-off below which we defined disability in all three cohorts. The Era cohort was considered the most representative of the military as it represented 80% of the UK Armed Forces. The rationale for using a generic measure was to allow a comparison between Gulf and non-Gulf (Bosnia and Era) veterans which would be unbiased by different distributions of symptoms or assumptions about the nature of ill health in Gulf and non- Gulf veterans. This definition of ill health was designed to identify subjects whose disability was most likely to be clinically significant. Gulf veterans who reported impaired physical functioning below the cut-off were defined as disabled Gulf with those above the cut-off defined as non- disabled Gulf. Bosnia and Era veterans who reported impaired physical functioning below the cut-off were defined as disabled non-Gulf.
References:
1. Sharief MK, Priddin J, Delamont RS, et al. Neurophysiologic analysis of neuromuscular symptoms in UK Gulf War veterans. Neurology 2002:59: 1518-1525
2. Unwin C, Blatchley N, Coker W et al. Is there a Gulf War syndrome? Lancet 1999; 353: 179-182
3. Ismail K KK, Brugha T, Hotopf M, et al. The mental health of UK Gulf war veterans: phase 2 of a two-phase cohort study. British Medical Journal 2002;325:576-579.