In order to address this issue, we analyzed the amyloid induction capability of samples from individuals affected by MCI (considered as a pre-symptomatic version of AD) and NDAN (which would correspond to an a-symptomatic form of the disease).
In the same population there was an 8.5% incidence of AFL having a 1 1 conduction ratio, a highly symptomatic form of AFL [ 24].
For example, if lead exposure were related not to ALS risk but in fact to slower progression (longer survival), or to a more benign (less symptomatic) form of disease, then lead-exposed cases might be more likely to enroll in the study.
Moreover, epidemiological studies have clearly shown that the risk of developing HL be up to three times higher in subjects with a previous history of infectious mononucleosis the symptomatic form of primary EBV infection, particularly frequent in adolescence than in other subjects [15].
3 A prospective study conducted in France in 1994 had estimated the annual incidence of the symptomatic form of childhood CD to 1/2500.
The nature of the pain observed in temporomandibular joint dysfunction is similar to that in the symptomatic form of neuralgia and significantly different from that in the spontaneous neuralgia [ 2, 15– 28].
In incidental Lewy body disease, which may be considered as a pre-symptomatic form of PD [ 16] and is present in up to 10% of individuals over the age of 60, GSH depletion is already present in the substantia nigra [ 18], and thus appears to precede complex I dysfunctions, iron accumulation and striatal dopamine loss [ 38].
One may wonder whether focusing on symptomatic cases might have biased the study towards the identification of risk factors more prone to lead to symptomatic forms of infection.
However, we have not found in the literature evidence of factors associated with symptomatic forms of infection, except for older age [18].
Searches of Medline and Central were performed and included nonsymptomatic and symptomatic forms of GJH (JHS, collagen diseases).
