Aprosodia, Aprosody

Contents

  1. Definition and Core Concepts
  2. Clinical Classification and Subtypes
  3. Pathophysiology and Anatomical Correlates
  4. References

Definition and Core Concepts

Aprosodia or aprosody (also referred to as dysprosodia or dysprosody) is a neurological deficit characterized by the inability to produce or comprehend the nonlinguistic aspects of spoken language. While standard aphasia involves a loss of grammar or vocabulary, aprosodia involves the loss of "prosody"—the speech melody, intonation, cadence, rhythm, and accentuations that convey or imply a speaker's emotion and attitude.

Patients with aprosodia may speak in a flat, monotone voice, unable to convey anger, joy, or questioning through their tone, or they may be entirely unable to detect these emotional cues when listening to others speak.

Conceptual illustration of speech prosody and emotion

Aprosodia is the loss of the "music" of speech, leaving a patient unable to convey or interpret the emotional coloring of language.

Clinical Classification and Subtypes

Aprosodia can be classified in a manner analogous to the major aphasia syndromes (such as Wernicke's and Broca's aphasias), reflecting a functional-anatomic organization primarily within the right cerebral hemisphere:

  • Sensory (Posterior or Receptive) Aprosodia: Characterized by an impaired comprehension of the emotional overtones of spoken language or emotional gesturing. Also known as "affective agnosia," patients with this subtype cannot tell if a speaker is angry, sad, or happy based on tone of voice alone.
  • Expressive/Motor (Anterior) Aprosodia: An inability to produce emotional overtones in one's own speech, resulting in a flat, monotone delivery. This is sometimes referred to as "emotional dysprosody" or, rather confusingly, speech dyspraxia. The patient feels emotion internally but cannot vocalize it.

Pathophysiology and Anatomical Correlates

Just as the left hemisphere is typically dominant for the propositional and linguistic aspects of language (grammar, syntax, semantics), the right hemisphere is broadly dominant for the emotional and prosodic aspects of language.

  • Right Hemisphere Lesions: Sensory aprosodia typically reflects pathology in the right posterior temporoparietal region. It may be clinically associated with visual extinction and anosognosia. Expressive aprosodia may occur in isolation with right-sided anterior (frontal) lesions.
  • Left Hemisphere Lesions: Dysprosody can also occur with left hemisphere damage, but in these cases, it is usually a secondary consequence of linguistic or motor speech deficits, such as the agrammatism seen in Broca’s aphasia or the severe articulatory difficulty in aphemia.

 

References

Monrad-Krohn GH. Dysprosody or altered "melody of language." Brain 1947; 70: 405-415

Ross ED. The aprosodias: functional-anatomic organization of the affective components of language in the right hemisphere. Archives of Neurology 1981; 38: 561-569

 

Cross References

Agnosia; Anosognosia; Aphasia; Aphemia; Broca’s aphasia; Fisher’s sign; Visual extinction