10 Most Common Causes Of Slurred Speech

Clear speech relies upon the precise coordination of various muscular subsystems involved in respiration (breath), phonation (voice/vocal fold vibration), articulation, and resonance. Any changes or disturbances to the muscles engaged in these processes can potentially disrupt the synchronicity of the motor-speech mechanism leading to instances of slurred speech.

Slurred speech is a term used to describe imprecise articulation or decreased articulatory accuracy and clarity when speaking. It can arise due to various underlying factors. In this post, we explore common causes of slurred speech, emphasizing the importance of understanding these factors for obtaining effective intervention.

Neurological Disorders

One of the leading causes of slurred speech is the presence of a neurological disorder. Any condition that disrupts typical brain function such as a stroke, traumatic brain injury, tumor, or progressive neurological condition such as Parkinson’s disease, can disrupt the strength and coordination of the muscles required for speech.  Neurological changes interfere with the communication signals between the brain and the muscles responsible for speech. This makes it challenging to precisely coordinate these muscles leading to slurred or unclear pronunciation.

When slurred speech arises in face of neurological conditions that affect how muscles control and coordinate the organs required for speaking, it’s termed dysarthria. Speech therapy is a cornerstone of dysarthria treatment. For more information on dysarthria and dysarthria treatment see our posts on Slurred Speech: What Causes Dysarthria? and The Impact of Stroke on Communication: Unveiling Aphasia and Dysarthria and A Guide to Speech Therapy for Parkinson’s Disease and How Brain Injuries Affect Your Speaking Ability

Medication Side Effects

Certain medications, known for their impact on the central nervous system, may cause slurred speech as a side effect. These may include drugs prescribed for pain management, muscle relaxants, or medications that induce sedation. It is crucial for individuals to communicate openly with physicians and attending healthcare professionals about any changes in speech patterns while taking medications to ensure safety and assess and adjust treatment plans accordingly.

Alcohol and Substance Use

Excessive alcohol consumption and substance use can impair cognitive function and motor skills, leading to slurred speech. Alcohol and various substances have an impact on the central nervous system which can alter the muscular control and precise coordination of organs involved in speech production. 

Dehydration and Overhydration (Hyponatremia)

Inadequate hydration can affect various bodily and neurological functions, including speech. Dehydration reduces saliva production, leading to dryness in the mouth and difficulties easily executing fine motor movements needed to articulate words clearly.  In severe cases, dehydration may induce harmful neurological consequences including delirium and confusion resulting in incoherent thoughts and overall reduced control and coordination of the subsystems of speech which are required to produce crisp clear words. 

Overhydration, a condition medically termed hyponatremia, can affect the balance of electrolytes in the body, more often leading to low sodium levels. These imbalances may also alter neurological function and impact clarity and precision of speech sounds. 

Fatigue and Exhaustion

Prolonged periods of fatigue and exhaustion can compromise muscle strength, control, and coordination, including those responsible for speech. Individuals experiencing extreme tiredness may find their speech becoming effortful and slurred due to muscular fatigue affecting articulatory precision. 

Infections and Illnesses

Certain infections affecting the respiratory system or causing generalized muscular weakness can contribute to slurred speech. Conditions such as the flu, pneumonia, or other illnesses that lead to fatigue and weakness may impact the body’s ability to optimally coordinate the substems of breath, phonation (voice), articulation, and resonance with enough strength and precision to articulate words crisply. 

Anxiety and Stress

Emotional factors, particularly anxiety and stress, can manifest physically and affect speech. Individuals experiencing heightened stress levels may find themselves struggling with slurred speech due to increased muscle tension affecting breath patterns as well as the function of the larynx or orofacial muscles. Speech therapy can provide training in exercises and strategies to increase strength and coordination involved in healthy voice production, reducing tension and improving vocal health and comfort.

Structural Issues in the Mouth or Throat

Physical differences or structural issues in the mouth and tongue can contribute to slurred speech. Conditions such as a tongue-tie or structural differences in the lips, tongue, or palate can affect the timing, range of motion, and strength of speech muscle movements. In such cases, decreased articulatory precision may be observed.  Sometimes medical or surgical interventions may be considered along with speech therapy interventions to address the underlying structural concerns.

Allergic Reactions

Severe allergic reactions, especially those leading to swelling or inflammation in the mouth and throat, can result in slurred speech. Anaphylaxis, a life-threatening allergic reaction, can cause rapid swelling of the tongue and difficulty in breathing, impacting speech clarity. Immediate medical attention is crucial in such situations.

Migraines and Seizures

Certain neurological events, such as migraines or seizures, can temporarily affect speech patterns. In the case of migraines, the associated aura may involve language disturbances, including slurred speech. Seizures, which affect the electrical activity in the brain, can also lead to alterations in speech.

Understanding the many underlying causes of slurred speech is essential for accurate diagnosis and effective intervention. Whether stemming from neurological issues, medication side effects, or emotional factors, addressing the root cause is key to restoring clear speech. Intensive speech programs for neurological disorders from Open Lines offer individuals facing neurological changes a pathway to improved communication and enhanced quality of life. Open Lines Voice Therapy Programs for Adults offers speech therapy for adults looking for lasting solutions to a variety of speech and voice needs.

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Our trained speech-language pathologists have years of experience to help treat your speech conditions.

Contact Open Lines® today by phone at 212-430-6800, by email at [email protected], or through our contact form to schedule a treatment.

If you’re struggling with communication difficulties, it’s time to turn to Open Lines®. Contact us via phone (212-430-6800), email [email protected], or by filling out our convenient contact form. Improve your communication skills and unlock your potential with Open Lines® Speech and Communication in New York today!