Alzheimer's and Mild Cognitive Impairment Diagnostic Protocol

Patients with probable AD and ADMCI were recruited consecutively from April 2015 to March 2022 at the outpatient clinic in the Department of Psychiatry in Nippon Life Hospital. All patients met the diagnosis criteria of probable AD and ADMCI according to the National Institute on Aging-Alzheimer’s Association (NIA-AA)^{61 (link),62 (link)} and the DSM-V⁶³ . Inclusion criteria for AD and ADMCI patients were as follows: (1) no comorbidity of other types of dementia, neurological, or psychiatric disorders; (2) not taking antidementia, antipsychotic, or antianxiety drugs; and (3) no lacunar cerebral infarct lesions or ischemic changes greater than would be expected for the patient’s age on head MRI. 91 drug-free probable AD patients and 11 drug-free ADMCI patients met the inclusion criteria. One AD patient was excluded due to the lack of 120-s resting awake artifact-free EEG segments. Finally, 90 drug-free probable AD patients and 11 drug-free ADMCI patients were included in this study. During follow-up of the 11 ADMCI patients, six patients developed AD, one patient maintained cognitive function within normal limits in MMSE and ADAS-J cog, two patients have not yet had follow-up examinations one year after diagnosis, and two patients discontinued outpatient care. The 147 healthy subjects used in the present study were obtained from our previous study^{64 (link)}. The healthy subjects (without history of any neurological or psychiatric disorders) underwent clinical tests to ensure that their memory and other cognitive functions were within normal limits (MMSE: 29.7 ± 0.6; global Clinical Dementia Rating: 0). The mean age of healthy subjects (58 women and 89 men) was 49.7 ± 19.6 years (Table 1).
This study was approved by the ethics committee of Nippon Life Hospital and conducted according to the Declaration of Helsinki. Written informed consent was obtained from all capable patients or their families.