Discriminant validity and reliability of the Turkish version of Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE-T).

The Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) has been used as a measure of cognitive decline in different cultures. The purpose of the study was to establish the validity and reliability of the Turkish version of IQCODE (IQCODE-T) and the ability of the questionnaire to distinguish between older adults with DSM-IV-TR dementia (n = 100) and healthy control participants (n = 60). In addition, the power of the IQCODE-T to distinguish between patients with depression and dementia was investigated. The Mini-Mental State Examination (MMSE) was performed on all participants and the IQCODE-T was administered to their informants. The IQCODE-T, which was not associated with age or education of the patients, significantly differentiated patients with dementia and controls. The IQCODE-T also correctly classified 73% of depressed patients as "non-demented". Because it is easy to administer, not associated with age/education and yields fewer false-positive results than the MMSE in depression, the IQCODE-T can be used in the detection of dementia.

[The factor structure of schizophrenic symptoms: which model is supported by independent item analysis?]. / Sizofreni belirtilerinin faktör yapisi: bagimsiz madde analizi nasil bir modeli destekliyor?

OBJECTIVE: Most studies that have investigated the symptom dimensions of schizophrenia utilizing the Scale for the Assessment of Positive Symptoms (SAPS) and the Scale for the Assessment of Negative Symptoms (SANS), both global rating scales, favored a 3-factor model. Only a few studies have examined the factor structure at the item level and they suggest a wider dimensional structure. The factor structure of schizophrenic symptoms has not been previously studied in Turkey, nor has the construct validity of these scales. The present study sought to determine the factor structure of the independent items and the construct validity of the scales. METHOD: The study included 180 schizophrenia patients (diagnoses based on DSM-IV criteria). The standard statistical methods of principal component analysis (PCA) and varimax rotation were used to extract factors. RESULTS: PCA of the global items yielded a 3-factor solution, representing positive, negative, and disorganization dimensions. Item-level factor analysis revealed 12 factors: Psychomotor poverty, positive formal thought disorder, auditory/visual hallucinations, social and occupational dysfunction, bizarre delusions, attention/stereotypy, paranoid features, somatic hallucinations/delusions, appearance, grandiose/religious delusions, inappropriate affect, and delusions of jealousy. CONCLUSION: Consistent with previous studies, neither the global nor the item-level factor structures supported the simple positive-negative dichotomy or the composition of the sub-scales; therefore, future studies should make use of the single items, especially when positive symptoms are being studied.