The German Intelligibility in Context Scale (ICS-G): reliability and validity evidence

Area of Science:

• Speech-language pathology
• Psycholinguistics
• Child development

Background:

• The Intelligibility in Context Scale (ICS) is a parent-report screening tool for functional speech intelligibility.
• It assesses intelligibility with various communication partners in real-life situations.
• The ICS has been translated into 60 languages, including German.

Purpose of the Study:

• To evaluate the psychometric properties of the German translation of the ICS (ICS-G).
• To assess the reliability and validity of the ICS-G using objective measures of speech sound disorder (SSD) severity.
• To determine the construct and criterion validity of the ICS-G.

Main Methods:

• Recruited typically developing (TD) children and children with SSD (n=181) in Germany.
• Parents completed the ICS-G; speech skills were assessed using PLAKSS-II for SSD severity (n=30).
• Test-retest reliability was analyzed with a subsample (n=36) after 1 week.

Main Results:

• The ICS-G demonstrated high internal consistency (α = .95) and test-retest reliability (r = .998).
• Significant correlations indicated good construct validity and criterion validity with PCC, PICC, PVC, and PPC measures.
• The ICS-G effectively discriminated between TD children and children with SSD.

Conclusions:

• The ICS-G exhibits strong psychometric properties, supporting its use in clinical and research settings.
• This validated tool aids speech-language pathologists (SLPs) in assessing German-speaking children with SSD.
• The ICS-G provides valuable insights into functional speech intelligibility from a parent's perspective.