J Korean Med Sci.  2024 Sep;39(37):e247. 10.3346/jkms.2024.39.e247.

Validity of the Tablet-Based Digital Cognitive Test (SCST) in Identifying Different Degrees of Cognitive Impairment

• An D
• Shin JS
• Bae N
• Seo SW
• Na DL

• KMID: 2559778
• DOI: http://doi.org/10.3346/jkms.2024.39.e247

Abstract

Background
As society ages, the incidence of Alzheimer’s disease and other dementias has surged, highlighting the importance of early dementia diagnosis. The Seoul Cognitive Status Test (SCST), a digital neuropsychological test, is designed for the early detection of cognitive impairment and has been standardized to establish reliability and validity. This study aims to verify whether the SCST effectively discriminates between groups based on three cognitive statuses (subjective cognitive decline [SCD], mild cognitive impairment [MCI], Dementia) in a large sample. We also seek to determine whether the SCST discriminates between individuals with three different cognitive statuses as defined by the Cognitive Dementia Rating (CDR).
Methods
We enrolled 254 participants from a dementia clinic who underwent a comprehensive neuropsychological battery (Seoul Neuropsychological Screening Battery-II) during the dementia evaluation by experienced neurologists (55 with SCD, 126 with MCI, 73 with dementia). In addition, the degree of cognitive decline in participants was classified by CDR level (186 with CDR 0.5, 52 with CDR 1, 15 with CDR 2). One-way analysis of variance was used to compare SCST scores according to each of the three cognitive status groups and CDR levels.
Results
The SCST total score, cognitive domain scores (attention, language, visuospatial function, memory, executive function), and most of the subtest scores decreased significantly in the order of SCD, MCI and dementia. Likewise, the differences in SCST scores between CDR levels were significant, particularly in distinguishing between CDR 0.5 and CDR 1.
Conclusion
This study reaffirmed that the SCST can significantly discriminate between groups of individuals with SCD, MCI, and dementia based on a large sample. Furthermore, differences in SCT scores were found across the levels of CDR, confirming the clinical utility of the SCST. These findings suggest that the SCST is an efficient and useful neuropsychological test for the sensitive detection of early cognitive impairment.

Keyword

Seoul Cognitive Status Test; Tablet-Based Cognitive Test; Alzheimer’s Disease; Mild Cognitive Impairment; Subjective Cognitive Decline; Dementia

Figure

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  Fig. 1 SCST total and domain scores in the SCD, MCI, and Dementia groups. (A) Attention score, (B) language score, (C) visuospatial function score, (D) memory score, (E) frontal/executive function score, and (F) total score.The y-axis represents the raw score for each cognitive domain score and the total score.SCST = Seoul Cognitive Status Test, SCD = subjective cognitive decline, MCI = mild cognitive impairment.

• 

  Fig. 2 SCST total and domain scores according to CDR 0.5, 1, and 2. (A) Attention score, (B) language score, (C) visuospatial function score, (D) memory score, (E) frontal/executive function score, and (F) total score.SCST = Seoul Cognitive Status Test, CDR = Clinical Dementia Rating.

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  Fig. 3 Compare ROC curves for the SCST total and K-MMSE scores between (A) SCD and MCI, (B) SCD and cognitively impaired group (MCI + Dementia), (C) Dementia and non-dementia group (SCD + MCI).ROC = receiver operating characteristic, K-MMSE = Korean version of the Mini-Mental State Examination, SCST = Seoul Cognitive Status Test, SCD = subjective cognitive decline, MCI = mild cognitive impairment.

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