Stuttering vs. Cluttering: How to Spot the Difference

SLP showing child patient letters

Cluttering is a condition affecting the fluency of speech that is typically characterized by perceived rapid and disorganized speech that often results in a communication breakdown. It is estimated that on average, at least one-third of children and adults who are diagnosed with stuttering have a cluttering component to their speech.1 This means that we as speech-language pathologists may be missing an important component of treatment.

As they share many commonalities, it’s no wonder that there is confusion between these diagnoses. Stuttering and cluttering fall under the same diagnosis code: Childhood Onset Fluency Disorder (F80.81).2 But they are quite different, and it’s important for us to be able to confidently assess those differences in order to provide the most effective intervention.

The Big Differences

Fluency diagnoses may be identified and differentiated through a combination of diagnostic testing, clinical judgment, and the individual and/or caregiver report.

First, gather subjective measures on your initial impressions of your client’s speech. Trusting your eyes, ears, and clinical thought will make this process easier! Focus in on these common differences between stuttering and cluttering:

  1. Tension: A frequent characteristic of stuttering is disfluencies that are accompanied by physical tension. Often you will SEE and HEAR this tension, but this is not always the case. In contrast, cluttering behaviors do not commonly involve physical tension, and you may observe minimal if any tension at all during speech. A person who clutters often exhibits rapid, disorganized, or seemingly “mushy” speech that may be difficult for the listener to follow.
  2. Secondary Behaviors: Due to minimal tension, people who clutter may not exhibit secondary behaviors that are often seen in people who stutter.
  3. Awareness: Some research has found that people who clutter may have reduced awareness of their specific speech differences.3 In contrast, people who stutter are generally aware of the specific speech disfluencies that make communication difficult for them.
  4. Emotional Response: Because of the increase in awareness for people who stutter, there is often an increase in the overall emotional response to those stuttering moments. People who clutter may have a less emotional response to their specific speech differences, but instead have an overall emotional response to their communication difficulties in general.3 This is due, in part, to the reactions they may be receiving in situations where their listeners do not understand them.

Measuring Differences

Objective measurements are important too. These tools can help you evaluate a fluency disorder:

  1. Rate of Speech Measurement: The hallmark (but definitely not the only) symptom of cluttering is the rate at which the person speaks. Individuals who clutter appear to present with a significantly faster rate of speech, and this can be apparent in both subjective and objective measurements. Rate is often not an issue for those who stutter, possibly due to increased tension that extends the time it takes for them to speak.4
  2. Types of Disfluencies: Unlike the tension-related disfluencies seen in stuttering, the disfluencies that present in cluttering may include are an excessive amount of typical disfluencies.4 The types of disfluencies more often related to each condition area include:
    • Cluttering:
      • Phrase repetitions
      • Word repetitions
      • Interjections
      • Revisions
    • Stuttering:
      • Part-word repetitions
      • Sound prolongations
      • Blocks
  3. Intelligibility of Speech: Many people who clutter may present with decreased intelligibility of speech as a result of decreased articulatory accuracy in connected speech.4 An intelligibility count should be taken across multiple contexts to measure this, as well as to further differentiate fluency disorders from articulation disorders.
  4. Language: In cluttering, there is a breakdown in overall language formulation. A formal language sample is highly recommended, as you will often observe frequent mazes and revisions that contribute to the decreased “flow” of language being expressed.

Can a Client Stutter and Clutter?

Yes! It is actually quite common for stuttering and cluttering to co-occur.3 It is common for cluttering to co-occur with other diagnoses, such as attention-deficit/hyperactivity disorder (ADHD) or a learning disability.3

Differential diagnosis requires you to trust your clinical judgment, your measurements, and, crucially, the client’s perceptions and experiences. When you are noticing overlapping symptoms, take a step back and ask yourself, “What is impacting this patient’s ability to be an effective communicator?” This answer is where you should begin in your treatment process.

Talk to Your Client (and/or Their Caregivers) About Their Speech

It may seem obvious, but differential diagnosis requires asking lots of questions! Start by listening to what your client says about their speech and their experiences. It is also helpful to talk to people in the client’s environment about their perceptions of everyday communication. Then, listen to your client’s speech patterns to seek confirmatory or complementary evidence. Familiarize yourself with the significant indicators of both cluttering and stuttering to become more confident evaluating and treating these common conditions that affect speech fluency.

  1. American Speech and Hearing Association (2022).
  2. Sanz, A. (2022). Diagnostic and Statistical Manual of Mental Disorders, Text Revision (DSM-5-TR). American Psychiatric Association, 2022. https://doi. org/10.1176/appi. books. 9780890425787. Psicooncología: investigación y clínica biopsicosocial en oncología, 19(2), 339-340.
  3. Van Zaalen, Y. & Reichel, I. (2015). Cluttering: Current views on its nature, diagnosis, and treatment. Bloomington, IN. iUniverse.
  4. Van Zaalen, Y., Wijnen, F., & Dejonckere, P. (2009) Differential diagnostics between cluttering and stuttering. Journal of Fluency Disorders. 34(3), 137-154.