Table I.

Psychometric Tests

The following tests were administered according to the test manual instructions:

1. Raven's Standard Progressive Matrices test (Raven, Court & Raven, 1992) – Non-verbal intelligence was assessed by the Raven's-SPM test. This task requires participants to choose the item from the bottom of the figure that would complete the pattern at the top. The maximum raw score is 60. Test reliability coefficient is .9

2. Digit Span from the Wechsler Adult Intelligence Scale (WAIS-III; Wechsler, 1997) - In this task participants are required to recall the names of the digits presented auditorily in the order they appeared with a maximum of total raw score 28. Task administration is discontinued after a failure to recall two trials with a similar length of digits. Test reliability coefficient is .9

3. Rapid Automatized Naming (Denkla, & Rudel, 1976) - The tasks require oral naming of rows of visually-presented exemplars drawn from a constant category (RAN colors, RAN categories, RAN numerals, and RAN letters). It requires not only the retrieval of a familiar phonological code for each stimulus, but also coordination of phonological and visual (color) or orthographic (alphanumeric) information quickly in time. The reliability coefficient of these tests ranging between .98 to .99.

4. Woodcock Reading Mastery Test Word Identification and Word Attack subtests (Woodcock & Johnson, 1990). The Word Identification subtest measures participants’ ability to accurately pronounce printed English words, ranging from high to low frequency of word occurrence with a maximum of total raw score 106. Test reliability coefficient is .97. The Word Attack subtest assesses participants’ ability to read pronounceable nonwords varying in complexity with a maximum total raw score of 45. Test reliability coefficient is .87. Task administration is discontinued when 6 consecutive words are read incorrectly.

5. Sight Word Efficiency (i.e., rate of word identification) and Phonemic Decoding Efficiency, (i.e., rate of decoding pseudowords) subtests from the Test of Word Reading Efficiency (TOWRE-II; Torgesen et al., 1999) were used to measure reading rate. The test contains two timed measures of real word reading and pseudo word decoding. Participants are required to read the words aloud as quickly and accurately as possible. The score reflects the total number of words/nonwords read correctly in a fixed 45-s interval. Task administration is discontinued after 45 seconds. Sight word efficiency maximum raw score is 108. Phonemic decoding efficiency maximum raw core is 65. Test-retest reliability coefficients for these subtests are .91 and .90 respectively.

6. Spoonerism Test (adapted from Brunswick et al., 1999) - This test assesses the participants’ ability to segment single syllable words and then to synthesize the segments to provide new words. For example, the word pair “Basket Lemon” become “Lasket Bemon”. The maximum raw score is 12.