Human speech is far more than an arbitrary assembly of words and syntactic rules; it is an intrinsically musical medium animated by fluctuations in pitch, duration, rhythm, and intensity. When neurological injury or disease disrupts the neural architecture that orchestrates this vocal melody, individuals experience aprosody—a profound impairment in the ability to express or comprehend the emotional and grammatical contours of spoken language. Stripping spoken dialogue of its affective warmth, nuance, and communicative color, aprosody often leaves patients sounding robotic, emotionally detached, or unable to decipher the conversational intentions and feelings of others.
Aprosody
1. Concise Definition
Aprosody is a neurological and neuropsychological disorder characterized by the inability or impaired capacity to properly produce, comprehend, or repeat prosody—the melodic, rhythmic, and intonational elements of spoken language. It encompasses deficits in both affective prosody, which signals emotional states such as anger, sorrow, or joy, and linguistic prosody, which communicates grammatical distinctions such as sentence mode, emphasis, and contrastive stress.
Clinically, aprosody is classified into expressive (motor) subtypes, where the individual is unable to modulate acoustic parameters such as pitch variation, volume, and speech timing despite intact emotional feelings, and receptive (sensory) subtypes, where the individual cannot interpret the emotional tone, irony, or grammatical inflection in the voices of others. Although classically attributed to lesions within the non-dominant (typically right) cerebral hemisphere, aprosody can also arise from subcortical pathology, diffuse axonal injury, neurodegenerative disorders, and severe neuropsychiatric syndromes.
2. Etymology & Linguistic Origin
The term aprosody is derived from the Classical Greek prefix a- (ἀ-), meaning “without” or “lacking” (the privative alpha), combined with prosōidía (προσῳδία), which translates literally to “song sung to music” or “the tune or accent of a syllable.” The Greek root prosōidía is itself a compound formed from pros (πρός, meaning “toward” or “in addition to”) and ōidē (ᾠδή, meaning “song” or “ode”). Historically, the term in ancient Greek linguistics denoted the variation in pitch accents, syllabic quantities, and vocal modulation accompanying recited poetry and rhetoric.
In twentieth-century medical and linguistic literature, the root was first adapted by the Norwegian neurologist Georg Herman Monrad-Krohn in 1947, who introduced the term dysprosody to describe foreign accent syndrome and related alterations in vocal melody following brain trauma. In 1981, American behavioral neurologist Elliott D. Ross formally introduced the systematic neurological construct of aprosodia (often used interchangeably with aprosody) to designate clinical syndromes of emotional-prosodic deficits analogous to Paul Broca and Carl Wernicke’s classic taxonomy of aphasia.
3. Pronunciation & Grammatical Form
In standard medical and linguistic English, aprosody is pronounced phonetically as /eɪˈprɒsədi/ or /æˈprɒsədi/. The noun form designates the general condition or phenomenon. The plural form is aprosodies, which refers to the distinct clinical and neuroanatomical subtypes of the condition.
The related lexical term aprosodia (/eɪprəˈsoʊdiə/) is widely preferred in behavioral neurology and neuropsychiatry, reflecting its historical mirroring of the term aphasia (plural: aprosodias). The adjectival form is aprosodic (/ˌeɪprəˈsɒdɪk/), used to describe speech patterns, vocal contours, or patient profiles (e.g., “an aprosodic vocal delivery”). An individual exhibiting the disorder is occasionally referred to as an aprosodic patient.
4. Detailed Conceptual Explanation
To fully understand aprosody, one must distinguish between the lexical-syntactic content of an utterance and its suprasegmental acoustic architecture. Spoken communication operates across two concurrent information channels: the verbal channel, which conveys propositional, symbolic content through phonemes, morphemes, and syntax; and the prosodic channel, which conveys paralinguistic and emotional meaning through continuous physical variations in the acoustic waveform. These variations depend upon four core acoustic parameters: fundamental frequency (pitch and pitch variability, denoted as $F_0$), amplitude (intensity and dynamic loudness range), duration (tempo, syllabic elongation, and pause patterns), and spectral tilt (vocal quality, resonance, and timbre).
Aprosody disrupts the central neurological encoding, decoding, or integration of these acoustic parameters. When an individual suffers from expressive aprosody, their voice is typically described as monotonic, flat, robotic, or uninflected. Even when the speaker experiences intense grief, excitement, or rage, their acoustic output remains rigidly flat, with negligible fundamental frequency variation, unvarying volume, and metronomic rhythm. Conversely, receptive aprosody cripples the listener’s ability to decode the affective valence or communicative intent behind vocal shifts. An individual with receptive aprosody may hear a speaker yelling in terror or whisper-chuckling with irony, yet perceive the utterance purely as an emotionally neutral proposition.
Crucially, aprosody operates across two primary domains: affective prosody and linguistic prosody. Affective prosody communicates primary and secondary emotional states (e.g., distinguishing an enraged “Get out!” from an affectionate “Get out!”). Linguistic prosody governs communicative grammar and discourse structures, including the distinction between declarative statements and questions based on terminal pitch contours (e.g., “You are going home.” versus “You are going home?”), syntactic chunking (parsing ambiguous phrase boundaries through pauses), and contrastive emphasis (e.g., “I did not take your keys” versus “I did not take your keys”). While right-hemisphere damage predominantly degrades affective prosody, complex left-hemisphere injuries or subcortical disruptions can impair linguistic prosody, demonstrating the intricate distributed nature of the prosodic network.
The boundaries of aprosody must be carefully circumscribed. It is distinct from peripheral neuromuscular dysfunctions such as dysarthria, wherein mechanical constraints of the vocal tract, tongue, or pharynx distort articulation. Aprosodic patients frequently possess entirely normal neuromuscular speech apparatus and clear articulation, yet lack the central neural control required to modulate emotional inflection. It is also structurally distinct from classical aphasia; an individual can suffer severe aprosody with completely preserved vocabulary, grammar, reading, and writing, or conversely, exhibit fluent emotional prosody despite catastrophic global aphasia.
5. Historical Development
The neuroscientific understanding of vocal melody emerged long after the 19th-century establishment of classical aphasiology. Although John Hughlings Jackson observed in the 1870s that patients with catastrophic left-hemisphere damage and total loss of propositional speech could still emit emotionally laden exclamations and melodic swearing, the clinical study of prosodic deficits was largely sidelined by the dominant scientific focus on left-hemisphere language specialization.
In 1947, Norwegian neurologist Georg Herman Monrad-Krohn published his landmark monograph documenting the case of Astrid L., a Norwegian woman who sustained severe shrapnel trauma to the left cerebral hemisphere during World War II. Upon regaining her speech, she exhibited an altered rhythmic and melodic inflection that caused fellow Norwegians to perceive her as speaking with a thick German accent. Monrad-Krohn introduced the terms hyperprosody (excessive musicality), hypoprosody (diminished musicality), and dysprosody (distorted musicality), asserting for the first time that the melodic components of speech constituted an independent domain of brain-based semiotics.
During the late 1970s, Kenneth Heilman and his colleagues at the University of Florida began systematic experimental work demonstrating that patients with right-hemisphere cortical lesions showed profound impairments in comprehending emotional prosody, establishing that the non-dominant hemisphere played a specialized role in non-verbal affective communication. Building upon this empirical work, neurologist Elliott D. Ross published a seminal 1981 paper in Archives of Neurology titled “The Aprosodias: Functional-Anatomic Organization of the Affective Components of Language in the Right Hemisphere.” Ross proposed a comprehensive functional-anatomical model that directly mirrored the classic Wernicke-Lichtheim model of left-hemisphere aphasia, categorizing the aprosodias into motor, sensory, global, transcortical, and conduction subtypes based on specific right-hemisphere cortical and subcortical lesion sites.
Throughout the 1990s and early 2000s, the introduction of functional neuroimaging (PET and fMRI) transformed the historical model of rigid right-hemisphere lateralization. Researchers such as Marc Pell, Sonja Kotz, Dirk Wildgruber, and Karsten Specht showed that while the right hemisphere exhibits preferential sensitivity to slow acoustic modulations and affective valence, prosodic processing relies upon a bilateral fronto-temporal-subcortical network. This modern phase integrated aprosody into mainstream cognitive neuroscience, exploring its presence in basal ganglia disorders like Parkinson’s disease, traumatic brain injuries, autism spectrum conditions, and schizophrenia.
6. Theoretical Foundations
Multiple neurocognitive and psycholinguistic frameworks have been formulated to explain the mechanisms governing prosody and the etiology of aprosody:
The Right-Hemisphere Hypothesis: Formulated by Heilman, Ross, and colleagues, this theory posits that the right cerebral hemisphere is uniquely specialized for the production, perception, and integration of non-linguistic, affective communication. According to this framework, the right hemisphere possesses a functional-anatomical architecture that parallels the left hemisphere’s language circuitry. Damage to the right inferior frontal gyrus produces expressive aprosody (akin to Broca’s aphasia), whereas damage to the right superior temporal gyrus causes receptive aprosody (akin to Wernicke’s aphasia), connected by the right arcuate fasciculus.
The Acoustic Cue / Functional Lateralization Framework: Advanced by David Poeppel and Sophie Scott, this model explains prosodic processing through biophysical signal processing rather than strict emotional-versus-linguistic dichotomies. The Asymmetric Sampling in Time (AST) hypothesis argues that the left auditory cortex is optimized for temporal resolution over short integration windows (~20–40 milliseconds), essential for phonemic discrimination and lexical decoding. In contrast, the right auditory cortex is optimized for spectral resolution over longer temporal integration windows (~150–300 milliseconds), making it exquisitely sensitive to the slow fundamental frequency excursions, melodic contours, and rhythmic variations that constitute prosody.
The Dual-Stream Model of Affective Prosody: Adapting the dorsal and ventral stream architecture of language to prosody, this model posits that prosodic perception begins in primary and secondary auditory cortices bilaterally, progressing into the right superior temporal sulcus (STS) to extract paralinguistic voice cues. From the right STS, a ventral stream projects to the right anterior temporal lobe and inferior frontal cortex for semantic, social, and emotional evaluation, while a dorsal auditory-motor integration stream interfaces with the right premotor cortex and frontal operculum for prosodic imitation, rehearsal, and expressive modulation.
7. Key Components, Types & Dimensions
Following the clinical-anatomical taxonomy established by Elliott Ross and subsequent neuropsychological revisions, aprosodic conditions are classified according to the specific functional domains and anatomical substrates affected:
- Motor (Expressive) Aprosodia: Characterized by an inability to impart emotional inflection or melodic modulation to spontaneous speech, repeat prosodic variations, or match vocal tone to internal affective states. Comprehension of affective prosody in others remains intact. Typically associated with lesions in the right frontal operculum (anatomically homologous to Broca’s area in the left hemisphere).
- Sensory (Receptive) Aprosodia: Characterized by severe difficulty or total failure in identifying and comprehending emotional and grammatical prosody in the speech of others. Spontaneous speech production retains normal, fluid melodic modulation. Typically associated with lesions in the right posterior superior temporal cortex (homologous to Wernicke’s area).
- Global Aprosodia: Characterized by the simultaneous destruction of both expressive and receptive prosodic capabilities. Patients can neither produce emotional vocal inflection nor decode it in conversational partners, often resulting from large right perisylvian strokes affecting frontal, parietal, and temporal cortices.
- Transcortical Motor Aprosodia: Characterized by flat, uninflected spontaneous speech coupled with preserved prosodic repetition abilities and intact affective prosodic comprehension. Associated with lesions disconnecting the right anterior prosodic production centers from supplementary motor areas.
- Transcortical Sensory Aprosodia: Characterized by intact spontaneous prosodic production and intact prosodic repetition, but a marked inability to comprehend or evaluate the emotional meaning of prosodic contours. Typically linked to lesions isolating the right posterior temporal-parietal junction from associative semantic regions.
- Conduction Aprosodia: A rare presentation where spontaneous emotional prosody and prosodic comprehension are preserved, but the patient exhibits a selective inability to repeat prosodic contours upon command. Classically attributed to damage along the right arcuate fasciculus or deep insular white matter tracts.
- Subcortical / Basal Ganglia Aprosodia: Characterized by a pervasive hypoprosody, marked by reduced fundamental frequency range, diminished vocal intensity, and impaired dynamic timing. Frequently observed in Parkinson’s disease, progressive supranuclear palsy, and focal basal ganglia or thalamic infarctions.
8. Examples & Illustrative Cases
Case Illustration 1: Acute Ischemic Right-Hemisphere Stroke. A 58-year-old corporate director sustained an acute ischemic stroke localized to the right inferior frontal gyrus and anterior insula. Neurological assessment confirmed completely intact lexical, grammatical, and syntactic speech; the patient scored normally on standard aphasia batteries. However, his family reported profound personality changes. When speaking of the recent birth of his first grandchild, his words were joyful (“I have never felt so completely delighted in my life”), but his acoustic delivery was flat, metronomic, and monotonic, devoid of pitch excursion or emotional cadence. When told that his beloved dog had died, his vocal response was delivered with the identical, uninflected pitch contour. Acoustic analysis using fundamental frequency tracking revealed a standard deviation of $F_0$ of less than 4 Hz throughout continuous discourse (normal reference range: 18–35 Hz). Expressive aprosodia left his family feeling that he had become cold, unfeeling, and pathologically indifferent, despite his internal feelings of profound distress.
Case Illustration 2: Subcortical Aprosody in Idiopathic Parkinson’s Disease. A 66-year-old retired schoolteacher with a five-year history of Parkinson’s disease developed progressive hypoprosody alongside hypophonia. During social interactions, she struggled to project emotional warmth or sarcastic wit. Her speech was characterized by reduced dynamic pitch variability, shortened phrase lengths, and prolonged pause intervals. In a clinical consultation, her spouse remarked that she “constantly sounded angry or bored.” Receptive testing revealed that she also experienced subtle deficits in distinguishing subtle variations between fearful and surprised voices. Her aprosodic symptoms led to social withdrawal and misdiagnoses of major depressive disorder with psychomotor poverty, when in fact her deficits were driven by striatal dopamine depletion within the basal ganglia-thalamocortical circuits that govern speech prosody.
9. Measurement & Assessment
Diagnosing and characterizing aprosodia requires a multimodal approach combining psychometric clinical batteries, perceptual psychophysical tests, and objective acoustic phonetics:
Standardized Neuropsychological Batteries:
- The Aprosodia Battery (Ross et al.): Evaluates six distinct communication behaviors across multiple primary emotions (happy, sad, angry, surprised, fearful, neutral). The behaviors include: spontaneous prosody production, prosodic repetition, comprehension of affective prosodic categories, discrimination of paired prosodic contours, and congruent versus incongruent prosodic-lexical matching.
- The Montreal-Toulouse Protocol for the Evaluation of Communication (MEC): Widely used in speech-language pathology to assess right-hemisphere communication disorders, offering standardized subscales for linguistic prosody (distinguishing statements from questions) and emotional prosody (production and comprehension).
- Profiling Elements of Prosodic Systems for Children and Adults (PEPS-C): A structured, psycholinguistically validated battery assessing communicative aspects of prosody including chunking, focus/stress placement, interactional affect, and question-statement intonation.
Acoustic Analysis: Objective quantification of prosody is conducted using phonetic analysis software such as Praat. Key objective markers include:
- Pitch Variability ($F_0$ SD): The standard deviation of the fundamental frequency across continuous speech samples, serving as the gold standard for vocal flatness.
- Mean Pitch Range: The difference between the highest and lowest fundamental frequency peaks during expressive emotional tasks.
- Vocal Intensity Dynamic Range (dB): Quantifies variations in volume, identifying mechanical and affective dynamics.
- Speech Rhythm and Pause Architecture: Ratio of vocalization time to silent pause duration, quantifying monotonic cadence and speech hesitation.
10. Applications & Practical Significance
The identification and treatment of aprosody hold vital importance across clinical neuropsychology, speech-language pathology, and psychiatric medicine. In acute clinical neurology, aprosody often goes undiagnosed because standard bedside assessments focus predominantly on left-hemisphere functions (e.g., naming, repetition, limb motor strength). When an uninflected, monotonic voice is mistaken for emotional apathy, clinical depression, or poor patient compliance, clinical management suffers.
In rehabilitation, targeted speech-language therapies have been developed to address aprosodic deficits. These interventions fall into two major paradigms: imitative (motoric) therapy and cognitive-linguistic therapy. Imitative therapies employ visual pitch biofeedback and hierarchical acoustic modeling, where patients repeatedly imitate the clinician’s exaggerated pitch contours, gradually fading cues until emotional inflection can be maintained independently. Cognitive-linguistic therapy, on the other hand, guides patients to verbally describe the acoustic characteristics of specific emotions (e.g., “anger requires a louder voice, elevated pitch, and rapid cadence”) and consciously incorporate these physical parameters into functional speech.
Caregiver psychoeducation represents another crucial application. Family members of patients with right-hemisphere stroke or Parkinson’s disease often interpret aprosodic delivery as emotional rejection, passive-aggressive detachment, or cognitive decline. By educating loved ones about the neurological distinction between internal emotional capacity and acoustic motor output, clinicians can mitigate social alienation, marital discord, and caregiver burnout.
11. Research & Empirical Evidence
Modern empirical investigations have illuminated the complex neural substrates underlying aprosody. Neuroimaging studies utilizing functional magnetic resonance imaging (fMRI) have demonstrated that the perception of affective prosody relies upon hierarchical processing along the right lateral temporal lobe. Research led by Sonja Kotz and Dirk Wildgruber has revealed that the posterior superior temporal sulcus (pSTS) functions as a specialized “voice area,” extracting acoustic features before routing them anteriorly to the middle superior temporal gyrus for affective categorization.
Diffusion tensor imaging (DTI) studies have mapped the structural disconnections underlying specific aprosodic phenotypes. Research confirms that disruption of the right arcuate fasciculus and the right superior longitudinal fasciculus impairs the integration of prosodic comprehension and expressive imitation, echoing the disconnection models long recognized in left-hemisphere aphasia syndromes.
Extensive empirical work by Marc Pell and colleagues on Parkinson’s disease has characterized the role of subcortical networks in prosodic regulation. Pell showed that basal ganglia pathology damages the internal timing mechanisms and dynamic parameter-scaling systems necessary to generate vocal pitch excursion and rhythm, demonstrating that aprosody is not exclusively a cortical right-hemisphere disorder, but can stem from disruptions in complex striato-pallido-thalamic-cortical loops.
12. Cultural & Cross-Cultural Considerations
The manifestation and assessment of aprosody are deeply mediated by linguistic and cultural contexts. The most striking division exists between non-tonal languages (such as English, Spanish, or German) and tonal languages (such as Mandarin Chinese, Thai, or Yoruba). In non-tonal languages, pitch variations ($F_0$) are deployed almost exclusively at the suprasegmental level to convey grammatical structures and emotional valence. In tonal languages, however, pitch height and pitch contour are phonemic: a change in pitch variation at the individual syllable level alters the lexical meaning of the word itself.
Remarkably, neurolinguistic research in Mandarin-speaking stroke patients indicates that tonal language speakers with right-hemisphere lesions exhibit profound affective aprosody while maintaining completely intact lexical tones, whereas those with left-hemisphere damage exhibit lexical tone errors with preserved affective prosody. This double dissociation illustrates that the brain segregates the communicative function of acoustic cues rather than the acoustic parameter itself: pitch carrying symbolic, phonemic value is processed predominantly in the left hemisphere, whereas pitch carrying affective, non-lexical value is lateralized to the right hemisphere.
Cultural display rules also heavily influence the clinical evaluation of aprosody. Societies vary considerably regarding baseline levels of vocal expressiveness, dynamic range, and normative vocal volume. In cultures characterized by high-context, emotionally restrained conversational norms, a lower baseline pitch variability may be misinterpreted by Western-normed assessment tools as pathological hypoprosody. Neuropsychologists must therefore interpret assessment results relative to appropriate ethnolinguistic baselines.
13. Criticisms, Debates & Limitations
The academic study of aprosody remains surrounded by theoretical debates and clinical controversies:
Critique of Ross’s Direct Mirror Model: While Elliott Ross’s classification provided an invaluable organizing framework, several behavioral neurologists and cognitive linguists have criticized the strict mapping of left-hemisphere aphasic syndromes directly onto the right hemisphere. Functional imaging and lesion-mapping studies frequently show that prosodic processing is far more widely distributed across bilateral neural circuits than classical aphasiology models suggest, with lesions rarely producing isolated, pure aprosodic subtypes identical to classical Broca’s or Wernicke’s aphasias.
The Valence Hypothesis versus Right-Hemisphere Dominance: A longstanding debate centers on whether the right hemisphere commands all emotional prosody, or whether affective lateralization is valence-dependent. The Valence Hypothesis posits that positive, approach-oriented emotions (such as joy) engage left-hemisphere networks, whereas negative, avoidance-oriented emotions (such as fear and anger) engage right-hemisphere circuits. Although evidence exists for valence-based modulation, clinical aprosodia most consistently follows right-sided or subcortical lesions regardless of emotional polarity.
Ecological Validity of Diagnostic Tools: Many clinical tests for aprosodia rely upon artificial, decontextualized tasks, such as having patients listen to semantically neutral sentences (e.g., “The grass is green”) read with simulated anger, sadness, or joy. Critics argue that these contrived tasks fail to capture the multi-sensory, dynamic nature of real-world discourse, where vocal prosody continuously interacts with facial expressions, body language, context, and semantic content.
14. Related Terms & Distinctions
Understanding aprosody requires clearly distinguishing it from related neurological, phonetic, and psychiatric phenomena:
- Dysprosody: An umbrella term denoting any qualitative distortion or abnormality in speech prosody (such as irregular cadence or foreign accent syndrome), whereas aprosody specifically denotes the near-total loss or absence of prosodic variation.
- Aphasia: An acquired loss or impairment of language faculties affecting symbolic-propositional communication, lexical retrieval, syntactic formation, reading, or writing, primarily caused by left-hemisphere injury. Aprosody preserves the lexical and syntactic structure of speech while erasing its musical and emotional overlay.
- Dysarthria: A motor speech execution disorder caused by weakness, paralysis, ataxia, or incoordination of the peripheral speech musculature. Aprosody, by contrast, is a higher-order cognitive-affective disorder that can occur in the complete absence of motor articulatory deficits.
- Alexithymia: A psychological construct characterized by an inability to consciously identify, differentiate, and name one’s own internal emotional states. Aprosodic individuals frequently experience rich, intact emotional awareness and empathy, but are neurologically unable to project those emotions through their vocal apparatus.
- Amusia: An acquired or congenital deficit in musical processing (the inability to perceive, produce, or appreciate music). While prosody and musicality share overlapping right-hemisphere auditory networks and acoustic properties (pitch, rhythm, timbre), amusia and aprosody can dissociate clinically.
- Blunted / Flat Affect: A psychiatric symptom classically observed in schizophrenia and severe depression, characterized by reduced emotional expressivity in voice, face, and gesture. While expressive aprosodia produces an identical acoustic profile, flat affect involves a profound reduction in affective experience and motivation, whereas aprosodia is an acoustic encoding/decoding disconnect.
15. Summary / Key Takeaways
Aprosody is the acquired or developmental disruption of the musical, rhythmic, and intonational dimensions of spoken language. It impairs both the production (expressive aprosody) and comprehension (receptive aprosody) of vocal emotion and linguistic emphasis, profoundly altering an individual’s communicative capacity.
Rooted anatomically in the non-dominant right cerebral hemisphere, basal ganglia, and fronto-temporal connecting tracts, aprosody decouples the lexical meaning of speech from its emotional and grammatical nuance. While often mistaken for depression, cognitive decline, or cold detachment, aprosodic patients typically retain full internal emotional awareness and intact linguistic vocabularies. Objective diagnostic protocols, computer-assisted acoustic analyses, targeted speech rehabilitation, and caregiver psychoeducation serve as the foundation for modern clinical management.
Ultimately, aprosody reveals that the human voice is a dual-channel instrument. While the verbal channel conveys our thoughts and concepts, it is the prosodic channel that breathes affective life into human dialogue, making vocal melody an essential biological architecture for empathy, social bonding, and shared understanding.
References
- Heilman, K. M., Scholes, R., & Watson, R. T. (1975). Auditory affective agnosia: Disturbed comprehension of affective speech. Journal of Neurology, Neurosurgery & Psychiatry, 38(1), 69–72. https://pubmed.ncbi.nlm.nih.gov/1127415/
- Monrad-Krohn, G. H. (1947). Dysprosody or altered “melody of language”. Brain, 70(4), 405–415. https://pubmed.ncbi.nlm.nih.gov/18903399/
- Pell, M. D., & Baum, S. R. (1997). The ability to encode emotional prosody following right or left hemisphere damage. Brain and Language, 58(2), 209–236. https://pubmed.ncbi.nlm.nih.gov/9178637/
- Poeppel, D. (2003). The analysis of speech in different time domains: Convergent evidence from psychophysics, neurobiology and neuroimaging. Cognitive Science, 27(2), 245–263. https://www.nature.com/articles/nrn738
- Ross, E. D. (1981). The aprosodias: Functional-anatomic organization of the affective components of language in the right hemisphere. Archives of Neurology, 38(9), 561–569. https://pubmed.ncbi.nlm.nih.gov/7212450/