Methods:
A total of 249 cancer patients from a university hospital (both outpatients and inpatients) in South Korea participated in the data collection from July 2012 to January 2014. The 3 clinical experts and 3 research experts evaluated content validity and the content-validity index was calculated. For internal-consistency reliability, Cronbach’s alpha and item-total correlations were evaluated. For convergent validity, Pearson’s correlations were tested with another validated cognitive impairment scale (The Functional Assessment of Cancer Therapy–Cognitive Function). For concurrent validity, Pearson’s correlations were tested with Functional Assessment of Chronic Illness Therapy–Fatigue. For known-group validity, t-test was performed to evaluate whether the measured cognitive impairment differed the in treatment experience groups. For factorial valdity, factor analysis was performed.
Results:
The newly developed measure, the Brief Perceived Cognitive-Impairment Scale, showed high internal consistency, with a Cronbach’s alpha of .92. Item-total correlations ranged from .76 to .81. In the content-validity index, all items were scored at higher than .80 and the scale was scored at higher than .92. The new measure was highly associated with another validated cognitive impairment measure (i.e., r = .93). The new measure showed moderate significant correlations with fatigue, a theoretically associated concept with the cognitive impairment (r = .54, p < .001). Factor analysis confirmed that the scale is unidimensional. The subjects undergoing treatment and the subjects expecting treatment statistically differed in the score of the Brief Perceived Cognitive-Impairment Scale (p < .05).
Conclusion:
The findings indicate that the new instrument is valid and reliable, for assessing cancer patients’ perceived cognitive dysfunction, particularly in concentration, memory, and executive functions. This instrument will be particularly useful in busy clinical settings and research studies examining multiple symptoms, because of its brevity.