To our knowledge the earliest known work relating cross-dominance to health was (Orton, 1925) and a series of articles in the April 1938 Journal of Juvenile Research.

The thesis by (Hajus, 1971) references these studies.

In one study (Eyre, 1938), cross-dominance was related to personality problems and effects on reading and writing. In another study, (Cornell, 1938), a relationship was found between cross-dominance and psychological problems. Other studies, (Dart, 1938) and (Turner, 1938), again confirmed that cross-dominant individuals were more likely to be unstable.

The origins of this particular work are due to two later researchers (Delacato, 1963; Trembly, 1968a; Trembly, 1968b). In (Trembly, 1968a), 98 children and students with poliomyelitis were studied. The incidence of cross-dominance among these students was significantly higher than normal, and those students who were cross-dominant were more likely to be more severely affected. In an another work (Trembly 1968b) a correlation was found between cross-dominance and ulcers. Trembly also found that cross-dominant individuals were more likely to chew their nails.

Trembly believed there was a clear reason for these correlations.

Trembly conjectured that cross-dominant individuals had a higher degree of neural tension. This neural tension causes an excessive amount of nervous energy. This energy could ultimately weaken the nervous system.

We comment here also about or choice of words. Our use of the phrase “neural tension” is different from the term “anxiety”. There is clearly some overlap in our usage, for both neural tension and anxiety are associated with a difficulty being able to “relax”. We do not believe cross dominance induces “fear” in an individual, but rather a kind of subtle inner hyperactivity of the nervous system.