Table 4.

Statistically abnormal performances on derived scores

Neuropsychological test and derived scores	Low values	High values	Interpretative considerations
	5th percentile/10th percentile	95th percentile/90th percentile
Trail making test, raw difference scoreTrail making test, ratio score	16/201.53/1.69	110/884.51/3.89	Low values indicate abnormally little interference from the additional demands of TMTB; higher values suggest marked declines with the inclusion of the switching condition from TMTB.
Difference between semantic and phonemic verbal fluency	−5/−3	22/19	Low scores suggest a statistically abnormal lack of benefit from semantic cueing; high values suggest abnormally large advantage for semantic fluency.
Percentage of Craft story retained	58.33/66.67	114.3/106.3	Low scores indicate statistically abnormal retention; high scores indicate infrequently high retention.
Percentage of Benson figure retained	41.18/50.00	100/94.12
Difference between percentage of Craft story and Benson figure retained	−21.86/−14.15	52.43/42.04	Low scores suggest unusually greater retention of visual information than verbal information; high scores suggest unusually greater retention of verbal than visual information.
Error index	0/0	7/5	Low scores represent error free performance, which is unusual even in normal control participants; high scores suggest abnormally elevated error rates.

Note: “Low” and “high values” refer to raw score values for the derived indices.