Validation of the Internal Coherence Scale (ICS) in Healthy Geriatric Individuals and Patients Suffering from Diabetes Mellitus Type 2 and Cancer.

Background: With increased life expectancy, the coexistence of functional impairment and multimorbidity can negatively impact life quality and coherence in geriatric individuals. The self-report 10-item Internal Coherence (ICS) measures how individuals cope with and make sense of disease-specific life challenges. The aim of this study was to validate the ICS in a sample of geriatric individuals.
Methods and Procedure: In a cross-sectional study, geriatric individuals with and without chronic diseases were recruited. A factor analysis with principal component extraction (PCA) and a structural equation model (SEM) was conducted to assess the ICS factor structure in a geriatric sample. To measure convergent validity, the following scales were used: Short Health Survey (SF-12), Karnofsky Performance Index (KPI), Trait autonomic regulation (Trait aR), Sense of Coherence Scale (SOC), and Geriatric Depression Scale (GDS).
Results: A sample of n = 104 (70-96 years of age) patients with Diabetes Mellitus Type 2 ( n = 22), cancer diseases ( n = 31) and healthy controls ( n = 51) completed the ICS. PCA and SEM yielded the original two-factor solution: 1. Inner resilience and coherence and 2. Thermo coherence. Overall internal consistency for this cohort was satisfying (Cronbach's α with r _α = 0.72), and test-retest reliability was moderate ( r _rt = 0.53). ICS scores were significantly correlated to all convergent criteria ranging between r = 0.22 * and 0.49 ** ( p < 0.05 *; p < 0.01 **).
Conclusion: Study results suggest that the ICS appears to be a reliable and valid tool to measure internal coherence in a geriatric cohort (70-96 years). However, moderate test-retest reliability prompts the consideration of potential age-effects that may bias the reliability for this specific cohort.