Professor Ken St. Louis is one of the pioneers in scientific research on cluttering. He has tried to better define cluttering by comparing potential cluttering individuals with stutterers and typical speakers. This comparative study has resulted in a working definition that is still widely used.
Besides an excessively high and/or irregular speech rate, one or more of the following core characteristics must be present:
- Excessive ‘normal’ disfluencies (like repetitions, sentence revisions)
- Excessive collapsing or deletion of syllables (telescoping, poor articulation)
- And/or abnormal pauses (too few, too short, etc.), syllable stress (wrong use of intonation or melody, monotony) or speech rhythm
In addition to the above-mentioned symptoms, St. Louis’ definition leaves room for other characteristics that are often seen in cluttering. Cluttering is often related to, for example, other communication disorders, language disorders, learning disabilities and/or attention disorders.