Cognitive Screening in Subjective Cognitive Decline

Individuals who were diagnosed as SCD were eligible for the study. Subjects who visited the hospital due to persistent cognitive worsening and were diagnosed with SCD after dementia work-ups are consecutively recruited. The dementia work up included detailed neuropsychological test battery, MRI, and routine blood sampling for syphilis, thyroid function, vitamin B deficiencies, and apolipoprotein epsilon genotyping. The inclusion criteria were as follows (Table 2): Age ≥ 60 years of age; Existence of persistent self-reported cognitive complaints; Normal performance (above −1.0 standard deviation [SD] of norms) on all subtests of neuropsychological test battery named Seoul Neuropsychological Screening Battery (SNSB);^{[4 ]} Clinical dementia rating (CDR) score of 0;^{[5 ]} Agreement to participate in the study and could visit the hospital for annual evaluations. The exclusion criteria were the following: Mild cognitive impairment (MCI) or dementia; Brain lesions known to cause cognitive impairment (tumor, stroke, or subdural hematoma); Any neurological disorders such as Parkinson’s disease, Huntington’s disease, epilepsy, or normal pressure hydrocephalus; Major psychiatric disorders such as uncontrolled depression, schizophrenia, alcoholism, or drug dependency; Abnormal blood laboratory findings such as abnormal thyroid function, low vitamin B12 or low folate, or positive syphilis serology, and; Hearing loss that is impossible to perform phone-based cognitive tests.