I searched PubMed for any relevant articles. I only found one article, from 1962, that attempted to measure this. They used some crude statistics and found that children who stuttered were less intelligent than their peers. I don't think this holds any water, especially considering the authors' long tangent about rural life and religious tendencies. (PMID: 6353066) I did, however, find a few articles about *perceived* intelligence which described two strategies to improve perceptions: 1. **Acknowledge your stuttering**. This also improves perceptions of personality and appearance, no matter mild or severe stuttering. (PMID: 2299842) 2. **Be Bold**. Individuals with stuttering or prolonged speech (from fluency-shaping therapy) are perceived as more pleasant, self-confident, and communicatively competent, compared to those with hesitent speech "i.e., a speech containing verbal avoidance behaviors like interjections and revisions." (PMID: 20947094)