Cognitive Impairment in Amyotrophic Lateral Sclerosis

Appendix e-1 Neuropsychological assessment and results

Neuropsychological assessment – cognitive domains and tests

- Premorbid intellectual ability: National Adult Reading Test, Dutch version, DART (2)

- Global cognitive functioning: MMSE (3)

- Attention and working memory:

Wechsler Adult Intelligence Scale-revised (WAIS-R) forward and backward digit span
WAIS-R letter-number sequencing (4)

- Executive functions:

Modified Wisconsin Card Sorting Test (MWCST) (5)
Category fluency (animals and supermarket items) (6)
Letter fluency or Controlled Oral Word Association Test (7)
Stroop Color-Word Test part C and “interference time” = Stroop part C - B (8)

- Psychomotor speed: Stroop Color Word Test Part A and B (8)

- Memory:

Rey Auditory Verbal Learning Test (9)
Rivermead Behavioral Memory Test (RBMT): immediate and delayed story recall (10)
Doors Test A and B (a visual recognition test) (11)

- Language: Boston Naming Test (BNT) (12)

- Visuospatial abilities: Judgment of line orientation test (JOLO) (13)

Neuropsychological assessment – procedure and adjustments for motor impairment

Five tests relied on speed: Stroop test parts A (word naming), B (color naming) and C (word interference on color naming), category and letter fluency. The Stroop test part A was used to control for a possible negative effect of dysarthria on the fluency tests, by generating the measure fluency-motor speed corrected, according to the following formula (for letter fluency):

Letter fluency-motor speed corrected = (180- (time per word for Stroop part A) * fluency score)

fluency score

Where fluency score = total amount of produced words with letters K, O and M in 180 seconds (60 per letter). The time per word for Stroop part A is the mean time (in seconds) it took the subject to pronounce a color-word. A similar formula for category fluency was used.

The Stroop test part B (color naming) and C (word interference on color naming) were not accommodated for motor impairment and results are not reported. These tests were used to calculate the Stroop interference time (Stroop C – Stroop B, not motor speed dependent).

Table: Neuropsychological test results in patients and controls: raw scores and p-values.

Values are mean (SD). Two sided p-values of <0.05 are considered significant (Student’s t-test or ANOVA), shown in bold. Here, we present p-values of all tests (PMA vs HC; ALS vs HC) irrespective of the ANOVA results to provide insight in the cognitive profiles of PMA and ALS patients. MMSE: Mini-mental state examination; WCST: Modified Wisconsin Card Sorting Test; Fluency motor speed corr. = motor speed corrected. RBMT: Rivermead Behavioral Memory Test; JOLO: judgement of line orientation.

References

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(2) Schmand B, Lindeboom J, van Harskamp F. Dutch Adult Reading Test. Lisse, The Netherlands: Swets and Zeitlinger, 1992.

(3) Folstein MF, Folstein SE, McHugh PR. "Mini-mental state". A practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res 1975;12:189-198.

(4) Wechsler D. Wechsler Adult Intelligence Scale-Revised (WAIS-R): Test Manual New York: Psychological Corporation, 1981.

(5) Nelson HE. A modified card sorting test sensitive to frontal lobe defects. Cortex 1976;12:313-324.

(6) Luteijn F, Barelds DPH. Groningen Intelligence Test 2 (GIT2): Manual. Harcourt Test Publishers, 2004.

(7) Benton A, Hamsher K, Sivan A. Multilingual Aphasia Examination, 3 ed. Iowa City: AJA Publishers, 1983.

(8) Stroop JR. Studies of interference in serial verbal reactions. J Exp Psychology 1935;18:643-662.

(9) Rey A. L'examen clinique en psychologie. Paris: Presses Universitaires de France, 1964.

(10) Wilson B, Cockburn J, Baddeley A. Rivermead behavioural memory test Reading, UK: Thames Valley Test Company, 1985.

(11) Baddeley A, Emslie H, NImmo-Smith I. Doors and People, a test of visual and verbal recall and recognition. Manual. London: Harcourt Assessment, 1994.

(12) Kaplan A, Goodglass H, Weintraub S. Boston Naming Test Philadelphia: Lea & Febiger, 1983.