Validation of the Internal Coherence Scale (ICS) in Healthy Geriatric Individuals and Patients Suffering from...

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.

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).

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 = 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 **).

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.