First time (seconds) to articulate (1 syll. words) First time (seconds) to articulate (3 syll. words) First time (seconds) to articulate (5 syll. words) Digit-symbol copy test (WAIS-III) Digit-symbol coding test (WAIS-R) PASAT score -.019, NS -.086, NS -.115, NS .211, p=.0245 .558,* p<.0001 PASAT % -.023, NS -.089, NS -.121, NS .213, p=.0231 .566,* p<.0001 Digit forward span -.055, NS -.018, NS -.051, NS -.143, NS .278, p=.0018 Digit backward span -.135, NS -.204, p=.0437 -.248, p=.014 .262, p=.0034 .342, p=.0001 Short-word span (1 syll. words) .014, NS -.029, NS -.007, NS .117, NS .246, p=.006 Long-word span (4 syll. words) -1,948E-4, NS .041, NS .065, NS .112, NS .212, p=.0176 Articulatory speed Time (seconds) to articulate (1 syll. words) .828,* p<.0001 .764,* p<.0001 .726,* p<.0001 -.605,* p<.0001 -.343, p=.0007 Time (seconds) to articulate (3 syll. words) .737,* p<.0001 .931,* p<.0001 .842,* p<.0001 -.586,* p<.0001 -.266, p=.0084 Time (seconds) to articulate (5 syll. words) .637,* p<.0001 .817,* p<.0001 .930,* p<.0001 -.639,* p<.0001 -.228, p=.0239 Dissimilar-letter span -.131, NS -.075, NS -.158, NS .211, p=.0183 .363, p<.0001 Similar-letter span -.127, NS -.187, NS -.177, NS .289, p=.0012 .301 p=.0008 Corsi forward span -.07, NS -.175, NS -.086, NS .257, p=.004 .243, p=.0067 Corsi backward span .005, NS -.017, NS -.01, NS .086, NS .225, p=.0118 a span test Initial word span -.109, NS -.122, NS -.078, NS .239, p=.0076 .243, p=.0066 Stroop test Reading: raw time .375, p=.0003 .396, p=.0001 .382, p=.0002 -.287, p=.0015 -.524,* p<.0001 Naming: raw time .295, p=.0041 .383, p=.0002 .409, p<.0001 -.34, p=.0002 -.545,* P<.0001 Interference: raw time .329, p=.0015 .416, p<.0001 .409, p<.0001 -.303, p=.001 -.534,* p<.0001 Flexibility: raw time .285, p=.0071 .314, p=.0031 .306, p=.0039 -.355, p=.0001 -.614,* p<.0001

Table 4: Correlations between the three indexes of processing speed and impaired performances of RRMS patients