Elsevier

Journal of Communication Disorders

Volume 44, Issue 6, November–December 2011, Pages 678-687
Journal of Communication Disorders

A one year prospective study of neurogenic stuttering following stroke: Incidence and co-occurring disorders

https://doi.org/10.1016/j.jcomdis.2011.06.001Get rights and content

Abstract

In this prospective study, data on incidence, stuttering characteristics, co-occurring speech disorders, and recovery of neurogenic stuttering in a large sample of stroke participants were assessed. Following stroke onset, 17 of 319 participants (5.3%; 95% CI, 3.2–8.3) met the criteria for neurogenic stuttering. Stuttering persisted in at least 2.5% (95% CI, 1.1–4.7) for more than six months following the stroke. Participants with comorbid aphasia presented with a significantly higher frequency of stuttering compared to the group without aphasia (U = 13.00, p(1-tailed) = .02) but no difference was found for participants with co-occurring dysarthria and/or cognitive problems. Participants with neurogenic stuttering did not differ from those without stuttering in terms of stroke risk factors or stroke etiologic subtypes. Although the incidence of stuttering following stroke is lower than that for aphasia or dysarthria, these results show that clinicians should take neurogenic stuttering into account when assessing stroke participants’ speech and language.

Learning outcomes

: Readers will be able to: (1) understand the need for systematic, prospective studies in neurogenic stuttering; (2) know the incidence and prevalence of neurogenic stuttering following stroke; and (3) know how neurogenic stuttering co-occurs with other speech-language disorders following stroke.

Highlights

► The incidence of neurogenic stuttering following stroke is 5.3%. ► Stuttering persists in 2.5% of the patients with neurogenic stuttering. ► Aphasia most frequently co-occurs in neurogenic stuttering following stroke.

Introduction

Neurogenic stuttering is an acquired speech disorder characterized by the occurrence of stuttering-like dysfluencies following neurological disease or insult. Stroke is the most common cause of neurogenic stuttering, followed by traumatic brain injury and neurodegenerative diseases (Theys, van Wieringen, & De Nil, 2008). Neurogenic stuttering has been defined in different ways. According to Helm-Estabrooks (1999), Stuttering Associated with Acquired Neurological Disorders (SAAND) is an acquired or reacquired disorder of fluency characterized by notable, involuntary repetitions or prolongations of speech that are not the result of language formulation or psychiatric problems. Duffy (2005, p. 355) has recently described neurogenic stuttering as “characterized by repetition, prolongation or blocking on sounds or syllables in a manner that interrupts the normal rhythm and flow of speech”.

Neurogenic stuttering most frequently has its onset in adulthood and differs in that way from developmental stuttering which typically starts in childhood. Some authors suggest that neurogenic and developmental stuttering also present with different characteristics. One of the first attempts to differentiate between neurogenic and developmental stuttering was published by Canter (1971), and later revised by Helm-Estabrooks (1999). She suggested that the following characteristics apply to neurogenic stuttering: (1) dysfluencies occur on grammatical words nearly as frequently as on substantive words; (2) the speaker may be annoyed, but does not appear anxious; (3) repetitions, prolongations and blocks do not occur only on initial syllables of words and utterances; (4) secondary symptoms such as facial grimacing, eye blinking, or fist clenching are not associated with moments of dysfluency; (5) there is no adaptation effect; and (6) stuttering occurs relatively consistently across various types of speech tasks. While other attempts to differentiate between the two fluency disorders have been published (Ringo & Dietrich, 1995), still others have cast doubt on these proposed differences in symptomatology and have suggested that the dysfluency characteristics of both types of stuttering may be more similar than previously thought (Stewart and Rowley, 1996, Theys et al., 2008, Van Borsel and Taillieu, 2001). Importantly, a recent comprehensive review of the literature has shown that differentiating characteristics of neurogenic or acquired stuttering may depend on the neurological condition that led to the stuttering (Nil, Rochon & Jokel, 2009). For example, syllable and word repetitions tend to occur more frequently following stroke and prolongations and blocks are more commonly reported following neurodegenerative disease (De Nil, Rochon, & Jokel, 2009). This has led to the current project which was aimed at providing a detailed analysis of the incidence, prevalence and co-occurring disorders of neurogenic stuttering following stroke, the etiology most commonly associated with neurogenic stuttering (Theys et al., 2008).

Strokes occur following a sudden interruption of the blood flow to a part of the brain. This may be caused by a blockage in a blood vessel (ischemic stroke) or by a rupture of an artery (hemorrhagic stroke, Hankey, 2002). Hypertension, smoking, hypercholesterolemia, diabetes mellitus and atrial fibrillation are known to be important stroke risk factors (Agostino, Wolf, Belanger & Kannel, 1994). In addition, strokes often result in subsequent speech-language problems. For example, aphasia occurs in 17–38% of subjects following stroke (Kyrozis, Potagas, Ghika, Tsimpouris, Virvidaki & Vemmos, 2009) and dysarthria in 8–30% of stroke participants (Urban et al., 2001). To date, no incidence data on neurogenic stuttering following stroke are available. Neurogenic stuttering has often been considered a rare phenomenon (Bloodstein and Bernstein-Ratner, 2007, Fawcett, 2005, Ringo and Dietrich, 1995). The low incidence of reports of neurogenic stuttering has recently been questioned given the many possible etiologies of this disorder (Lundgren, Helm-Estabrooks, & Klein, 2010). Furthermore, the labeling of neurogenic stuttering as a rare disorder appears to conflict with the observation that it is not uncommon for clinicians in medical settings to encounter participants with neurogenic stuttering (Nil, Jokel & Rochon, 2007). For example, in the survey study of Market, Montague, Buffalo, and Drummond (1990), 100 of the 150 clinicians initially contacted in the United States identified at least one patient with acquired stuttering in their caseload. This was also the case for at least one fourth of the therapists working with patients with neurological disorders in the survey study conducted in Belgium (Theys et al., 2008). These contrasting findings highlight the need for incidence data on neurogenic stuttering. Indeed, the answer to this question will indicate the likelihood that clinicians may encounter patients with such speech fluency disorders in their practice and determine to some extent the need for research on clinical diagnostic guidelines and intervention.

One of the limitations of previously published research on neurogenic stuttering following stroke is that it mostly consists of case studies (De Nil, Jokel, & Rochon, 2007). Studies describing groups of patients are either retrospective studies (Market et al., 1990, Stewart and Rowley, 1996, Theys et al., 2008) or studies on small participant samples combining stroke with other etiologies (Helm et al., 1978, Jokel et al., 2007). These latter studies may pose difficulties with interpretation and generalization of the findings as different neurogenic stuttering etiologies might elicit different characteristics of acquired dysfluencies (De Nil et al., 2009).

Despite the limitations of the available literature on neurogenic stuttering, some valuable information can be inferred from the published studies. Limiting the results to the largest etiology group of stroke-induced neurogenic stuttering, the mean age of the subjects at onset of their stuttering was found to be 60 years in the four cases reported by Grant, Biousse, Cook, and Newman (1999) and 67 years for the 29 stroke patients in the survey study by Theys et al. (2008). The age range in this last study varied from 35 to 92 years. While speech disorders following stroke, and in particular stuttering, can be expected to occur most often in adults, a single case of neurogenic stuttering following stroke in a 2-year-old has also been reported (Nass, Schreter, & Heier, 1994). The occurrence of neurogenic stuttering following stroke seems to be more common in males with gender differences reported from 2:1 (Theys et al., 2008), 5:1 (De Nil et al., 2009) to 10:1 (Mazzucchi, Moretti, Carpeggiani, Parma, & Paini, 1981). Also, the localization of the brain lesions in patients presenting with stuttering following stroke does not seem to be restricted to one specific brain area but involves all four cortical lobes and subcortical regions such as the thalamus, brainstem, basal ganglia and cerebellum (De Nil et al., 2009, Grant et al., 1999).

Neurogenic stuttering following stroke is often reported to co-occur with disorders such as aphasia, apraxia of speech, and dysarthria (Bloodstein and Bernstein-Ratner, 2007, Theys et al., 2008). This co-occurrence might hamper the diagnosis of neurogenic stuttering as the dysfluencies can be attributed to the presence of these other disorders. In the study by Jokel et al. (2007) five of the six patients with stroke-induced stuttering presented with mild aphasia, mostly expressed as anomia, one patient presented with mild apraxia and two with dysarthria. Helm-Estabrooks (1986) pointed out that acquired stuttering can co-occur with different types of aphasia such as Broca's aphasia, Wernicke's aphasia, amnestic aphasia, and conduction aphasia. The problem on the comorbidity of neurogenic stuttering and other speech language disorders was highlighted in a recent review of neurogenic stuttering (Lundgren, Helm-Estabrooks, & Klein, 2010, p. 448): “…it remains unclear whether acquired stuttering is a distinct disorder or an epiphenomenon of other motor speech disorders such as apraxia of speech”. However, reports of cases with neurogenic stuttering without any co-occurring speech-language disorders (e.g. Grant et al., 1999, Nass et al., 1994) point to the existence of neurogenic stuttering as a disorder per se. Clearly, a strong need exists for the further characterization of co-occurring speech-language disorders and their differential diagnosis with neurogenic stuttering.

The lack of precise incidence data, together with an unclear symptomatology and the co-occurrence of other speech-language problems, might result in difficulties with diagnosis and reduced awareness of neurogenic stuttering. Therefore, the current study was designed with the primary purpose to investigate the incidence and prevalence of neurogenic stuttering following stroke in a systematic prospective manner. The secondary purpose of this study was to provide systematic data on behavioral characteristics, co-occurring disorders, and recovery of neurogenic stuttering following stroke. These data are urgently needed because neurogenic stuttering can seriously affect the patient's ability to communicate, and an accurate diagnosis is necessary to ensure optimal therapeutic treatment tools can be developed.

Section snippets

Study population

All 582 patients admitted to the stroke unit of a university hospital in Leuven (Belgium) between September 1, 2006 and August 31, 2007 were screened and considered for inclusion in the study (Fig. 1). Of these, 238 patients were excluded because their symptoms were diagnosed to result from a transient ischemic attack, subdural hemorrhage, subarachnoidal hemorrhage, brain tumor, traumatic brain injury or epilepsy not in accordance with the definition of stroke (Hankey, 2002). Another 15

Study population

Of the 319 participants screened in the acute phase (Fig. 1), 46 (14%) did not survive during the course of the study. An additional 14 participants could not be screened during any of the three follow-up sessions due to their poor medical condition. As a result, at the one month follow-up screening 264 of 295 (89%) surviving participants could be contacted. At the three month follow-up screening, 165 of 285 (58%) participants were seen in the hospital and at the one year follow-up screening

Discussion

This study is the first large systematic study of the incidence and prevalence of acquired stuttering in the acute and chronic phase after stroke. Based on our data, neurogenic stuttering occurs in 5.3% of stroke participants (95% CI, 3.2–8.3) and is observed persistently in at least 2.5% (95% CI, 1.1–4.7) more than six months after stroke. In the current study participants were referred for in-depth fluency testing up to one year post-stroke onset. However, the likelihood of the referrals

Acknowledgments

Dr. Eric Manders, and Herlinde Dely are acknowledged for their reassessment of the dysarthria and stuttering scores, respectively. We thank Mies Van Gils and Mileen de Frene for their help with transcribing the conversations. We are also grateful to Dr. Evy Visch-Brink for providing us a pre-published version of the ScreeLing and to Dr. Rik Vandenberghe for facilitating our access to the stroke unit at the University Hospitals Leuven. This study was partially funded by the Research Foundation

References (43)

  • R. Boey

    Stotteren: detecteren en meten

    (2000)
  • G.J. Canter

    Observations on neurogenic stuttering: A contribution to differential diagnosis

    British Journal of Disorders of Communication

    (1971)
  • L. Caplan

    An investigation of some aspects of stuttering-like speech in adult dysphasic subjects

    Journal of the South African Speech and Hearing Association

    (1972)
  • E.G. Conture

    Stuttering

    (1990)
  • R.M. Crum et al.

    Population-based norms for the Mini-Mental State Examination by age and educational level

    Journal of the American Medical Association

    (1993)
  • B. Dabul

    Apraxia battery for adults. (2nd ABA-2)

    (2000)
  • R.B. D’Agostino et al.

    Stroke risk profile: adjustment for antihypertensive medication. The Framingham Study

    Stroke

    (1994)
  • L.F. De Nil et al.

    Stuttering associated with acquired neurological disorders: Review, assessment and intervention

  • L.F. De Nil et al.

    Adult-onset neurogenic stuttering

  • R. Dharmaperwira-Prins

    Dysartrie en verbale apraxie: beschrijving, onderzoek en behandeling

    Lisse: Swets & Zeitlinger

    (1996)
  • J.R. Duffy

    Motor speech disorders. Substrates, differential diagnosis and management

    (2005)
  • Cited by (0)

    View full text