A Case of Psychogenic Acquired Stuttering: “A Solution in Search of an Explanation”

About the authors:

ISAD 2015 (Byrd photo)Tessa Byrd is currently a second year graduate student striving to attain her Master’s Degree in Communication Sciences and Disorders at Western Carolina University (Cullowhee, North Carolina, USA). For her Bachelor of Science Degree, she studied Communication Sciences and Disorders at the same university. She fell in love with the program and decided the charming school tucked into the mountains was her heaven. Tessa is blessed with two loving, supportive parents who recently moved to North Carolina. She is eager to work with all people who have communication disorders and is particularly interested in serving people who stutter.
ISAD 2015 (Baxley photo)Beth Baxley, MS, CCC/Speech-Language Pathology, is a clinical Speech-Language Pathologist who has been in practice for 31 years. She has worked primarily in hospitals, home health agencies, and skilled nursing facilities, specializing in adult neurogenic speech, language, and swallowing disorders. She is a former adjunct faculty member of Western Carolina University (Cullowhee, North Carolina, USA).  She is also a beekeeper and is currently assisting her husband, Steve, and daughter, Lauren, in pursuing their lifelong dream of opening a chocolate shop in Sylva, North Carolina (USA).
ISAD 2015 (Shapiro portrait)David A. Shapiro, Ph.D., CCC/Speech-Language Pathology, is a Fellow of the American Speech-Language-Hearing Association, a Board Certified Specialist in Fluency and Fluency Disorders, and the Robert Lee Madison Distinguished Professor at Western Carolina University (Cullowhee, North Carolina, USA). For 38 years, Dr. Shapiro has taught workshops, provided clinical service, and conducted research on six continents. His book, Stuttering Intervention: A Collaborative Journey to Fluency Freedom (2011, PRO-ED, www.proedinc.com) is in its 2nd edition and continues to find a wide international audience. Dr. Shapiro is actively involved in the International Fluency Association (IFA) and International Stuttering Association (ISA), received IFA’s Award of Distinction for Outstanding Clinician, and served as IFA’s President from 2012-2014. Dr. Shapiro is a person who stutters, has two adult children with his wife, Kay, and lives near the Great Smoky Mountains National Park.

There are relatively few cases of psychogenic acquired stuttering reported in the literature. This paper addresses one such case, which revealed “a solution in search of an explanation” (Dworkin, Culatta, Abkarian, & Meleca, 2002, p. 222).

What is Psychogenic Acquired Stuttering?

Psychogenic acquired stuttering typically begins in adulthood in association with a psychological disturbance or emotionally traumatic event, with no association of a history of developmental stuttering or neuropathology. With some variation, the speech disfluency resembling stuttering begins abruptly, is characterized by repetition of initial or stressed syllables, is without secondary symptoms (i.e., learned reactions to the stuttering) or episodes of spontaneous  fluency, and does not reduce with fluency facilitating contexts (e.g., choral reading, white noise, delayed auditory feedback, singing, and different communication contexts). The person with psychogenic acquired stuttering may demonstrate atypical interpersonal interaction, consistent eye contact, absence of a stuttering pattern related to content or function words, absence of an adaptation effect (i.e., there is no reduction in stuttering with continued conversation or repeated readings), a history of previous mental health issues, and indifference personally to the disruption caused by stuttering (i.e., la belle indifférence). One of the hallmarks of psychogenic acquired stuttering is symptom reversibility, complete or near complete resolution of symptoms, as a consequence of a short term of management (Shapiro, 2011).

Case Summary

Harry (fictitious name), a man in his 20s, expressed concern about stuttering, which reportedly began suddenly within hours of a neurology appointment scheduled less than one month prior to a speech evaluation. Harry interpreted being told by the neurologist that his seizure disorder would cause progressive brain damage. Harry’s aunt, who accompanied him, corroborated this event as the precipitator of Harry’s stuttering. Harry wears a helmet to protect himself from potential harm during the seizures, which he indicated occur, with some variation, every day and evening. He stated that the seizures trigger headaches, loss of breathing, and unconsciousness, all of which he documents in a journal.

Significantly, the neurologist reported that Harry demonstrated “no difficulty speaking” and that his speech was “clear and appropriate.” He also reported that a previous emergency room evaluation for seizure activity was negative and that the seizures “represent psychogenic events.” There was no evidence of neuropathology, however, there was a positive history of mental illness (i.e., anxiety, conversion disorder, depression, and insomnia).

Harry reported no situations in which fluency improved (i.e., although fluency worsens when he is emotional, in pain, or trying to reduce disfluency), discussed various traumatic life events, and expressed a desire to make a presentation at an upcoming conference to discuss his struggle with stuttering. In an attempt to encourage others, Harry reported frequenting an electronic chat room designed for people with disabilities and interacting with people who stutter. Harry expressed an awareness of the literature on stuttering and a high level of personal anxiety and frustration related to his stuttering.

A conversational speech sample collected at the initial meeting revealed disfluency on 100% of the words spoken without secondary or learned reactions. Eye contact was consistent. All disfluencies were part-word repetitions, specifically replication of word-initial phonemes, ranging from two to seven units of repetition. Harry’s disfluency demonstrated no change in response to choral reading, singing, gentle onset, rhythmic speech, and tapping with reduced rate. There was no difference in degree or type of disfluency on content or function words and no observed adaptation effect.

Following the evaluation, Harry was seen for two treatment sessions. Both fluency shaping (behavioral procedures to eliminate stuttering) and stuttering modification (practice to alter the type and degree of stuttering, combined with discussion of related thoughts, feelings, and attitudes) were used, resulting in minimal change in disfluency. Intervention focused on transferring the observed fluency in the medial and final positions of words to the initial position. Speaking to the beat of a metronome, whether slow or fast, resulted in no change in disfluency. However, during slow, rhythmic speech, Harry reported a painful headache that only occurred when he tried to suppress disfluencies, so the activity was concluded. There seemed to be no identified phonemic pattern of disfluency; consistent disfluency continued on all word-initial sounds, whether vowel or consonant.

At the second treatment session, the clinician shared that the neurologist reported Harry’s speech to be without disfluency and seizures to be of non-neurogenic origin. Harry expressed being unable to explain the neurologist’s observations. When probed, Harry altered what he previously reported, now indicating that stuttering began more gradually the day before the neurology appointment. The session was concluded with a subsequent session scheduled.

A few days later, before the third scheduled treatment session, Harry left a voicemail message for the clinician, saying that his disfluency resolved completely in all speaking situations after the second treatment session. He stated that the onset of stuttering was related to lack of consistency in taking his medications and that the elimination of stuttering was due to greater medication compliance. Because Harry terminated treatment, the clinician followed up with two phone calls to Harry. Both revealed Harry’s speech to be without stuttering.

Discussion 

Consistent with the profile mentioned above, particularly symptom reversibility, Harry’s stuttering appeared to be of psychogenic origin. One exception was that Harry reported and demonstrated anxiety related to stuttering. Indeed, determining the type of disfluency can be challenging. Harry did not present a history of developmental stuttering, so this diagnosis was eliminated. Distinguishing between neurogenic and psychogenic acquired stuttering can be particularly challenging. Baumgartner (1999) concurred, stating “The presence of neuropathology does not mean the patient’s stuttering is neurogenic, and the presence of psychopathology may not mean it is psychogenic. Neurogenic and psychogenic disorders often coexist and the presence of one does not render a patient immune to the other” (p. 276).

We looked more closely at the possibility of neuropathology. As noted, the neurologist reported no evidence of neuropathology and that the seizures were likely psychogenic in origin. Nevertheless, it is possible that neuropathology went undetected. If that were the case, Spain, Mandel, and Sataloff (2006) have reported that epileptic seizures can induce stuttering. Furthermore, Rosenbek (1984) indicated, “About the only sites within the nervous system which have not been associated with stuttering are the occipital lobes of the brain, which are devoted primarily to vision and the cranial nerves once they leave the brainstem” (p. 43).

As stated, Harry demonstrated no neurologic evidence of seizures. Vossler et al. (2004) examined 230 patients experiencing seizures. Using a video-EEG, they found that 113 experienced true epileptic seizures and 117 experienced psychogenic non-epileptic seizures. All of the patients who exhibited disfluencies experienced psychogenic non-epileptic seizures. Often psychogenic stuttering and non-epileptic seizures co-occur. Reports of epileptic seizures inducing psychogenic disfluencies are few; more frequently non-epileptic seizures accompany psychogenic acquired disfluencies (Spain et al., 2006).

Another possible undetected neurogenic factor is antiepileptic medications, which also have been associated with stuttering. Gabapentin, a seizure medication, was reported to induce stuttering in one patient; that patient’s disfluency disappeared when he ceased use of the medication (Nissani & Sanchez, 1997). Harry had been on a long-term gabapentin prescription, which was not altered before or during the course of speech therapy. His other medications were researched and none were found to contribute to stuttering. It is unlikely, therefore, that Harry’s medications contributed to disfluency.

Malingering (i.e., pretending or faking stuttering) was another consideration due to the personal gain associated with receiving ongoing financial support for a disability from the government and anticipation of receiving praise for dealing with stuttering at the upcoming conference. Although malingering and neurogenic acquired stuttering were not completely excluded as possible contributing factors, psychogenic acquired stuttering better represented the client’s symptom and recovery patterns.

Harry is no longer receiving fluency treatment but continues to see a general practitioner, neurologist, psychologist, and counselor for his seizure disorder. Regardless of the precise diagnosis, Harry now is experiencing remarkable fluency success. Indeed we have found “a solution in search of an explanation.”

Additional Questions to Consider

Flower (1985) confessed, “Our unending questions and our ceaseless doubts in no way discredit our profession or our discipline. They may well be among our greatest assets” (pp. 24-25). In this positive and constructive spirit, many questions remain for consideration and further discussion.

  • Why is it important to differentiate between stuttering and other fluency disorders?
  • How can one distinguish between developmental stuttering, neurogenic acquired stuttering, psychogenic acquired stuttering, and malingering? What are the similarities and differences between the disorders in terms of behavioral, cognitive, and affective considerations? How might treatment considerations differ with each disorder?
  • Baumgartner (1999) indicated that neurogenic and psychogenic acquired stuttering can coexist and the presence of one does not eliminate the possibility of the other. How can the two disorders be distinguished? What might be the characteristics and treatment methods if a person has evidence of both?
  • Why is it still important to determine the type and cause of a fluency disorder after a solution was found and Harry is no longer stuttering?
  • Why is it beneficial to share clinical cases such as Harry’s? How does such sharing contribute to our understanding of fluency and fluency disorders?
  • Flower (1985) concluded that the most appropriate, honest, and positive salute to our profession and our discipline is “To bewilderment!” How might this toast relate to the questions raised by this paper and the challenges presented by Harry?

References

Baumgartner, J.M. (1999). Acquired psychogenic stuttering. In R. F. Curlee (Ed.), Stuttering and related disorders of fluency (2nd ed., pp. 269-288). New York: Thieme.

Dworkin, J. P., Culatta, R, A., Abkarian, G. G., & Meleca, R. J. (2002). Laryngeal anesthetization for the treatment of acquired disfluency: A case study. Journal of Fluency Disorders, 27, 215-226.

Flower, R. M. (1985). Asking questions. Asha, 27 (12), 21-25.

Nissani, M., & Sanchez, E. A. (1997). Stuttering caused by gabapentin. Annals of Internal Medicine, 126 (5), 410.

Rosenbek, J. C. (1984). Stuttering secondary to nervous system damage. In. R. F. Curlee & W. H. Perkins (Eds.), Nature and treatment of stuttering: New directions (pp. 31-48). San Diego, CA: College-Hill.

Shapiro, D. A. (2011). Stuttering intervention: A collaborative journey to fluency freedom (2nd ed.). Austin, TX: PRO-ED.

Spain, R., Mandel, S., & Sataloff, R. T. (2006). The neurology of stuttering. Journal of Singing, 62 (4), 423-433.

Vossler, D. G., Haltiner, A. M., Schepp, S. K., Friel, P. A., Caylor, L. M., Morgan, J. D., & Doherty, M. J. (2004). Ictal Stuttering: A sign suggestive of psychogenic nonepileptic seizures. Neurology, 63 (3), 516-519.

9,532 total views, 11 views today

Comments

A Case of Psychogenic Acquired Stuttering: “A Solution in Search of an Explanation” — 28 Comments

  1. How do we differentiate between a stutter that is neurogenic vs psychogenic? Is the main difference between the diagnosis of the two the presence of developmental stutter (which would have us believe it is neurogenic)? Are the treatment strategies for neurogenic and psychogenic acquired stuttering relatively similar?

    • Hi Hannah,

      Thank you for reading paper. This is a great question. Neurogenic stuttering and psychogenic stuttering have many commonalties. They both range from mild to severe, can have a variety of disfluency types, secondary characteristics are not common, and typically contain disfluencies that occur throughout the utterance. With all of these commonalities it can be difficult to differentiate between the two types. However, often the causes that surround the onset differ. Traumatic events that produce disfluenices typically produce psychogenic stuttering. Neurogenic stuttering is typically the result of neurological changes. Sometimes, theses changes can be detected by different medical tests. Treatment for the two types are similar. I used both fluency shaping and stuttering modification techniques. Sometimes, people who experience psychogenic stuttering feel indifferent toward stuttering. Often, people who experience neurogenic stuttering feel annoyed, but they may not feel anxious about stuttering. Discussions regarding feelings and beliefs about oneself as a communicator would differ based on the person’s perspective. Thank you for asking such a thoughtful question.

      Best,
      Tessa

  2. Very interesting client and paper. The etiology of the disfluency or stuttering must be a determining factor when attempting to differentiate psychogenic from neurogenic stuttering. Neurogenic stuttering typically is contributed to injury or disease to the brain or central nervous system. It seems to me that if your client was not lying about the changes/consistencies in medication dosages. That the changes in medications would affect his nervous system and brain, thus the the sudden onset of stuttering could be diagnosed as neurogenic. It too is possible that the client was malingering, but if the client expressed frustration related to stuttering, he must have put on a good act. I would not take one doctors report non neuropathology as concrete evidence. Was the doctor aware of the changes/inconsistencies with medication? Psychogenic stuttering is related stress emotionally traumatic events (Shapiro, 2011). I believe that children and adults can be diagnosed with psychogenic stuttering following many types of various trauma. Differentiating between “neurogenic” stuttering and “psychogenic” stuttering may be as hard as trying differentiate between the “brain” and the “mind”. The anatomy of the human brain is thoroughly documented the anatomy of the human psyche is only vaguely interrupted by psychologist, psychiatrist, philosophers and people with religious significance. The only thing that specifies a diagnosis of psychogenic stuttering is the lack of evidence related to any predisposing factors such as genetics, development or cognition. As far as this relates to the ABCs (affective, behavioral, cognitive) aspects of stuttering I feel that psychogenic stuttering is associated with negative affect a person experiences following a traumatic event. To begin to speak of trauma here now would only open Pandora’s Box. I would not diagnosis a client with psychogenic stuttering when there might be a plausible cognitive reason for onset of stuttering. The difference of diagnosis is found within the prefixes of the words themselves, neuro(nervous system, brain and psycho(mind, spirit, soul).

    Derek Taylor CCC-SLP

    References

    Shapiro, D. A. (2011). Stuttering intervention: A collaborative journey to fluency freedom (2nd ed.). Austin, TX: PRO-ED.

    • Hi Derek,

      Thank you for taking the time to write a comment. Indeed, this was a puzzling case. That is why it is so interesting and worth sharing. Unfortunately, our field is not always one of hard science. Rather, SLPs interpret what we can on the basis of all available data. When looking at the big picture, we felt psychogenic acquired stuttering was the most appropriate diagnosis. As I mentioned above, neurogenic stuttering as well as malingering are both possibilities by themselves or in combination with one another. This was an interesting and unique case; challenges are welcome. They raise insightful questions and encourage us to consider new viewpoints. Thank you for your comment.

      Best,
      Tessa

  3. I found this paper both interesting and insightful. I’ve never read about an individual who had a psychogenic acquired stutter. I wanted to know if you could elaborate on the slow, rhythmic speech used in therapy and how Harry reacted. Do you think he was trying to suppress his disfluencies, and as a result developed a headache? Or do you think this reaction was psychological as well?

    • Hi Lauren,

      What a wonderful question. The slow rhythmic speech used in therapy utilized evenness and gentleness to increase fluency. Have you ever read a text with others at the same time? There is a rhythmic pattern that allows the readers to say the words together. The speech we used sounded similar to the speech used for reading with others. Concerning your second question, it is possible that Harry could have developed a headache because he perceived suppressing disfluencies would induce a headache. It is incredible to consider the possible power of the mind.

      Best,
      Tessa

  4. Hi Tessa, Beth and David. I enjoyed reading your article on psychogenic acquired stuttering. It is interesting the idea that psychogenic stuttering emerges from a psychological disturbance or from an emotionally traumatic event. Since humans in the world are faced with much suffering and traumatic events, it is amazing that the psychogenic stuttering does not impact a larger number of people. Or, could psychogenic stuttering be prevalent but underreported?

    • Hi Lourdes,

      Thank you for taking the time to comment. You raised a good question. It is possible that psychogenic stuttering is relatively rare. It is also possible that it is underreported. Additionally, it could occur in conjunction with other types of fluency disorders. All three are possibilities. This is a great question. What do you think?

  5. You introduced this article stating that there are few reports of psychogenic acquired stuttering in the literature. Why do you think this is the case? Is it an uncommon condition or an under-researched topic? Have you treated many clients diagnosed with psychogenic acquired stuttering?
    Thank you for sharing your interesting experience in this article.
    C. Goldberg

    • Hi Chana,

      Thank you for commenting. I think the heart of your question is similar to Lourdes’ question. It truly is a great question. I’m unsure if psychogenic acquired stuttering is rare, underreported, or occurs in conjunction with other fluency disorders and receives less attention. Although the cause is unclear, there is limited research. Identifying why could lead to more research and a deeper understanding. Concerning your second question, this was my first client diagnosed with psychogenic acquired stuttering. Not many cases of psychogenic acquired stuttering are reported, and it was an interesting case. That is why I wanted to share it. Again, thank you for your comment.

      Best,
      Tessa

  6. Hello, thank you for sharing this truly unique case study! I’ve never heard of a client with a psychogenic acquired stutter and I found the case history and behaviors to be very interesting. You said that the client was only treated for two sessions, and that some activities were difficult due to his headaches. I wonder how much progress would have been made in therapy if he had not regained his fluency. Was this a concern for you at the time? Did you have plans to try different techniques due to the headaches caused by suppressing disfluencies?

    Thanks again,
    Madison

    • Hi Madison,

      Thank you for your thoughtful questions. Some techniques produced more frequent headaches than others, so we were focusing on the techniques that did not provoke headaches. Progress was a concern; we explored many different avenues to find highly effective techniques, and we contacted other professionals who worked with him in order to gain a better understanding of what might help. Thank you again for you questions!

      Best,
      Tessa

      Best,
      Tessa

  7. Hello Tessa. I would also like to thank you for sharing such an intriguing case. I find the nature of psychogenic stuttering fascinating and I am also interested to know what else you would have tried had Harry’s stutter persisted.

    Thank you,

    Heather

    • Hi Heather,

      That is a great question. As I mentioned to Madison, we planned to continue using the techniques that did not produce headaches. We also contacted other professionals that Harry worked with in order to gain a deeper insight into new treatment options. Thank you for taking the time to comment.

      Best,
      Tessa

  8. Hi Tessa,
    Thank you for sharing this interesting case study. I’d never heard of a case like this before. Had you suspected psychogenic acquired stuttering before the client called to say he did not stutter anymore? I was very surprised that his stuttering went away so quickly (I imagine you were too). Could this case still be diagnosed as psychogenic stuttering if the client’s stuttering had not subsided?

    Thank you for your time,
    Kari

    • Hi Kari,

      Indeed, it was a very interesting case. Before the disfluencies disappeared we considered psychogenic and neurogenic acquired stuttering as well as malingering. All three options are still possible in isolation or in combination with one another. Typically, psychogenic stuttering disappears quickly, but this might not always be the case. Each case is unique and often does not fit perfectly into one category. Thank you for the questions!

      Best,
      Tessa

  9. Hi Tessa,

    Thank you very much for sharing your experience in this particular case of psychogenic stuttering! I have two questions regarding the case. In your paper you shared that Your client did not experience fluency during tasks such as choral reading and singing. Is this typical for psychogenic cases? My second question is about the onset of your client’s stuttering. You stated that psychogenic stuttering is preceded by a traumatic event. Harry shared with you that his stuttering was preceded by his neurology appointment. Was the appointment traumatic for Harry or unrelated to what may have triggered the onset?

    Cheers,

    Katrina

    • Hi Katrina,

      It’s good to hear from you. Regarding your first question, typically it is more challenging for people who have psychogenic or neurogenic acquired stuttering to establish fluency during choral reading and singing but with more coaching fluency can often be established. Regarding your second question, it was evident that Harry was highly upset about what he perceived the neurologist to say. We believed that was the traumatic event that could have been the trigger. Very good questions. Thank you for taking the time to write a comment.

      Best,
      Tessa

      • Hi Tessa,

        Thank you for your response! I believe we discussed in our fluency class that in most cases of malingering, fluency cannot be established during tasks such as choral reading and singing. I imagine that this factor made it very difficult to diagnose the particular case. Also Lauren made a good point about Harry’s symptoms resolving shortly after seeing a psychologist. Very interesting!

  10. Hi Tessa,

    Thanks so much for sharing this paper! I recently just wrote a paper on psychogenic stuttering for my graduate fluency class, and boy was it hard to find both sources and to differentiate between neurogenic and psychogenic stuttering. My question is: Because Harry was seeing a psychologist, do you believe that this was the main reason his stuttering ceased? If so, do you think that the primary treatment for a psychogenic stutterer should be psychological consultation?

    -Lauren

    • Hi Lauren,

      Excellent question! It is very possible that multiple factors contributed to Harry’s fluency success. I feel psychologists play a critical role in helping patient’s who have psychogenic acquired stuttering, but I also feel SLPs do as well. When multiple disciplines focus on helping an individual the greatest outcomes are likely possible. Again, thank you for asking such a thoughtful question.

      Best,
      Tessa

  11. Thank you for sharing this case. I have never heard of psychogenic stuttering before. My first reaction when I read that he called to cancel the third appointment after being questioned about the neurologist visit on the second appointment was that he was malingering and it seemed like he was being “caught.” However, I don’t have any experience with psychogenic stuttering and it appears that you have ruled out other possibilities for a diagnosis. It is amazing to me that this type of disfluency can appear and disappear so suddenly. It has definitely given me something to think about.

    • Hi Kayla,

      Thank you for commenting on the paper. Indeed, it can be difficult to differentiate between malingering and psychogenic stuttering. It is even possible that both could be at work. We didn’t rule out any of the disfluency types; rather we selected the one that best fit the symptoms. It is possible that it was a combination of even more factors. Great comment!

      Best,
      Tessa

  12. Hi Tessa,

    This was such an interesting read. Today in my voice class we learned about psychogenic voice disorders so no wonder this article caught my eye.

    Are you familiar with other cases such as these? I am assuming they are pretty rare.

    I am also wondering how much stress/anxiety must be accumulated to cause this kind of stuttering? That question is probably silly. Just wondering if you had any insight!

    • Hi Layne,

      Thank you for commenting. You are so right. These cases are pretty rare, which makes them difficult to compare to other cases. You asked a good question. I’m not sure if there is a specific amount of stress that can cause this type of stuttering; it is likely different for each person, but it must be “traumatic”. Thank you for commenting!

      Best,
      Tessa

  13. Hey there Tessa,

    Thank you so much for sharing about this topic. I am curious about the contrast between most psychogenic cases being brought on more suddenly vs the chronic nature of mental health issues that often precipitate psychogenic stuttering. Additionally, when we consider anxiety as a mental health issue, I’m compelled to wonder whether psychogenic stuttering could be brought on by authentic neurogenic stuttering because of the anxiousness an adult may feel after beginning to stutter at an older age. Please write back, as this is less of a question and more of a concern I have had for several months since having had a client with neurogenic stuttering.

    Thank you so much,

    K. Riddle

    • Hi Katie,

      You asked a good question. It is interesting to consider the contrast between the chronic nature of mental health issues vs psychogenic stuttering. Unfortunately, I’m not sure there is a clear answer to your question about onset. I think your second question, is a valid theory. It is possible, but I’m not sure there are enough cases documented to find a clear answer. It could branch from the demands and capacities theory, having a later onset when demands are greater.

      I hope this helps.
      Best,
      Tessa

  14. Thanks for the response, Tessa. I think demands and capacities offers a really great lens for considering neurogenic stuttering as most adults who have not struggled with their speech prior to the sudden onset of stuttering caused by stroke or some other traumatic event might, themselves, magnify the demand for fluent speech as what is “normal”.

    Thanks again,

    K. Riddle