An Unusual Cause of Stuttering: A Case Report

Vague neurologic symptoms, including impaired speech, can be difficult to diagnose and – for female patients – dismissed as behavioral.

But commonly prescribed medications such as SSRIs may be a cause of movement disorders and speech disturbance. This case of adult-onset stuttering illustrates the importance of a thorough history and an open-minded approach.

Case

A 23-year-old patient with a history of depression, attention deficit hyperactivity disorder (ADHD), hyperlipidemia, and diabetes presented to the ED with a 2-week history of tremor and a new symptom of stuttering.

She first noticed the stuttering while trying to have a conversation with her manager 2 days prior to the ED visit and reported associated symptoms of difficulty forming sentences, confusion, and bilateral lower extremity weakness that had gradually worsened since the time of onset. The patient had not experienced fever, cough, chills, nausea, vomiting, diarrhea, shortness of breath, chest pain or abdominal pain. Vital signs were as follows: blood pressure 113/79 mmHg, pulse 63 beats/min, respiratory rate 17 breaths/min, and temperature 37°C.

Physical examination showed a patient in no distress. Cardiovascular, respiratory and abdominal examination was unremarkable. Cranial nerves II-XII were intact. Motor strength was 5/5 in all extremities. Sensation to light touch was intact. Reflexes were 2+ in all extremities. There was no clonus noted.

The patient was ambulatory with a normal gait. Pronator drift and Romberg sign were negative, and no nystagmus was observed. Assessment of the patient’s speech revealed an obvious stutter that was difficult to control. When the patient was asked to lift her head upwards, the emergency physician noted a tremor and titubation on extension of the neck.

ED evaluation included blood glucose, CBC with differential, CMP, HCG, CK, urinalysis, CT brain, MRI brain (Figure 1), and MRI cervical spine. Laboratory results were within normal limits aside from a very minimal leukocytosis at 10.96 and hemoglobin of 15.3 that was normocytic. There was no evidence of renal dysfunction, transaminitis, or anion gap acidosis.

Figure 1. MRI-brain

CT imaging was unremarkable.  MRI of the brain with and without contrast showed no acute intracranial disease. MRI of the cervical spine showed no evidence of abnormal cord signal or enhancement.

The patient later revealed she was taking sertraline to manage depression, and her dose of 50 mg per day was increased to 100 mg a few days before symptoms started.

Discussion

Movement and speech disorders are associated with multiple medications. Extrapyramidal symptoms (EPS) include motor dysfunctions such as dystonia, akathisia, parkinsonism, tremor, and tardive dyskinesia. Drug-induced parkinsonism encompasses a wide array of symptoms including tremor, rigidity, and/or bradykinesia. EPS commonly present in patients taking dopamine-blocking drugs; however, they can occur with other psychotropic medications, including antidepressants.¹ The pathogenesis of parkinsonism has been extensively studied in the setting of antipsychotic and dopamine blocking agents; however, cases have been documented with selective serotonin reuptake inhibitor (SSRI) use as well. Common risk factors for drug-induced parkinsonism are female gender, older age, current or prior use of antipsychotic medications, and prior history of movement disorder.²

The connection between SSRIs and movement disorders has been previously documented.^3,4  Tremor has been listed as the most common movement disorder side effect of SSRIs.⁵ Stuttering has also been shown to be associated with SSRI use. Symptoms typically resolve when the agent is discontinued.⁶

Stuttering can be developmental or acquired. Developmental stuttering presents during speech development in childhood at ages 3-9. Acquired stuttering is multifactorial and can be further divided into psychogenic and neurogenic categories. Neurogenic stuttering occurs after brain injuries or damage from drugs and toxins, while psychogenic stuttering appears in patients with psychiatric illness or emotional trauma.

The differential diagnosis of adult-onset stuttering includes traumatic brain injury, brain mass, stroke, epilepsy, drug abuse, psychogenic, medication induced, or chronic depression. Our laboratory and radiology results as well as a thorough history narrowed this list to medication induced stuttering. A literature review of drug-induced stuttering showed three publications describing stuttering caused by sertraline.⁷ Other medications associated with stuttering include theophylline⁸ antipsychotics,⁹ tricyclic antidepressants,¹⁰ memantine,¹¹ and pregabalin.¹² Additional speech changes can also be attributed to medication use. For example, topiramate, used in the treatment of seizure disorders and migraine, has been associated with echolalia¹³ and is known to negatively affect verbal fluency.¹⁴

It has been hypothesized that elevated dopamine levels contribute to stuttering.¹⁵ This hypothesis is further reinforced by findings of dopamine blocking medications used in successfully treating stutters.¹⁵ SSRIs, by definition, increase serotonin levels, but they also have been found to increase dopamine levels and play a role in movement regulation at the level of the basal ganglia. Interestingly, a prior study utilizing numerous SSRIs resulted in sertraline as the only medication in its class that was able to cause inhibition of dopamine reuptake in the striatum and nucleus accumbens.¹⁶ These findings, along with the temporal association of the stutter in our patient, further strengthen the working diagnosis of medication-induced stuttering. A very similar presentation with the same dosages was also documented in 1994.¹⁷

Case Resolution

After clinical assessment and workup in the emergency department, the patient was admitted to the hospital. The patient presented to the emergency department late in the evening. They were admitted overnight for monitoring, further imaging and neurology evaluation. The consulting neurologist noted the only abnormalities on neurologic examination were an apparent stutter and titubation with extension of the neck.

The patient’s presentation was determined to be secondary to a medication side effect. The hospitalist and neurology team agreed to the plan of titrating the sertraline dose back to the previously tolerated dose of 50 mg daily. The patient was discharged from the hospital the next day in stable condition with instructions to follow up with her psychiatrist.

Take-Home Points

• Commonly prescribed medications such as SSRIs may be a potential cause of movement disorders and speech disturbance. These unusual symptoms present a diagnostic challenge for the ED physician, and although not life-threatening, they can severely affect a patient’s quality of life.
• Female patients with seemingly vague neurologic complaints are often dismissed as having a behavioral component to their presentation.^18,19
• Women with ischemic strokes are less likely to have their symptoms recognized,²⁰ to undergo diagnostic testing, or to see a specialist.²¹

This report encourages emergency physicians to reflect on implicit biases and the tendency to overlook or downplay atypical neurologic symptoms. It also stresses the importance of taking a thorough and complete medication history.

References

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