More recently, Kay & Hanley (1991) and Price & Humphreys (1992) have argued that the deficit that produces letter-by-letter reading in alexic patients can differ across patients, with letter-by-letter reading simply being a compensatory strategy adopted by some patients to mitigate their residual impairment in reading words (see Coslett, Saffran, Greenbaum & Schwartz, 1993).
Finally, one pure alexic patient, DM (Bub & Arguin, 1995), has demonstrated spared lexical decision ability, but not the same relatively high performance levels at semantic categorization.
In contrast to the above cases, at least some alexic patients have been described who appear not to show covert reading (Patterson & Kay, 1982; Price & Humphreys, 1992).
The pure alexic patients described by Shallice & Saffran (1986) and Coslett & Saffran (1989) demonstrated above chance performance on forced choice semantic categorization, even where words were presented too briefly to be named explicitly.
Effects of word frequency and imageability on semantic categorization have not been reported for pure alexic patients.
Alexic patients are usually not perfect at letter naming, but their performance at letter naming is substantially superior to that at word naming; hence they may adopt a letter-by-letter reading strategy.
At the 33 per cent lesions, d[prime]s fall within the range of values reported for the pure alexic patients by Coslett & Saffran (1989) (d[prime] range: 0.675-1.30).
Alexics do not have direct access to the "whole word" system available through phonological processing (Black & Behrmann, 1994; even though some have access to a word recognition system in the RH, Funnell, 2000b).
The fact that the brains of some alexics have difficulty perceiving certain novel, complex visual stimuli cannot demonstrate that there is no reading module.