Aprosodia and prosoplegia with right frontal neurodegeneration.

Affective prosody and facial expression are essential components of human communication. Aprosodic syndromes are associated with focal right cerebral lesions that impair the affective-prosodic aspects of language, but are rarely identified because affective prosody is not routinely assessed by clinicians. Inability to produce emotional faces (affective prosoplegia) is a related and important aspect of affective communication has overlapping neuroanatomic substrates with affective prosody. We describe a patient with progressive aprosodia and prosoplegia who had right greater than left perisylvian and temporal atrophy with an anterior predominance. We discuss the importance of assessing affective prosody and facial expression to arrive at an accurate clinical diagnosis.

Decoding facial blends of emotion: visual field, attentional and hemispheric biases.

Most clinical research assumes that modulation of facial expressions is lateralized predominantly across the right-left hemiface. However, social psychological research suggests that facial expressions are organized predominantly across the upper-lower face. Because humans learn to cognitively control facial expression for social purposes, the lower face may display a false emotion, typically a smile, to enable approach behavior. In contrast, the upper face may leak a person's true feeling state by producing a brief facial blend of emotion, i.e. a different emotion on the upper versus lower face. Previous studies from our laboratory have shown that upper facial emotions are processed preferentially by the right hemisphere under conditions of directed attention if facial blends of emotion are presented tachistoscopically to the mid left and right visual fields. This paper explores how facial blends are processed within the four visual quadrants. The results, combined with our previous research, demonstrate that lower more so than upper facial emotions are perceived best when presented to the viewer's left and right visual fields just above the horizontal axis. Upper facial emotions are perceived best when presented to the viewer's left visual field just above the horizontal axis under conditions of directed attention. Thus, by gazing at a person's left ear, which also avoids the social stigma of eye-to-eye contact, one's ability to decode facial expressions should be enhanced.

Affective Prosody and Its Impact on the Neurology of Language, Depression, Memory and Emotions.

Based on the seminal publications of Paul Broca and Carl Wernicke who established that aphasic syndromes (disorders of the verbal-linguistic aspects of communication) were predominantly the result of focal left-hemisphere lesions, "language" is traditionally viewed as a lateralized function of the left hemisphere. This, in turn, has diminished and delayed the acceptance that the right hemisphere also has a vital role in language, specifically in modulating affective prosody, which is essential for communication competency and psychosocial well-being. Focal lesions of the right hemisphere may result in disorders of affective prosody (aprosodic syndromes) that are functionally and anatomically analogous to the aphasic syndromes that occur following focal left-hemisphere lesions. This paper will review the deductive research published over the last four decades that has elucidated the neurology of affective prosody which, in turn, has led to a more complete and nuanced understanding of the neurology of language, depression, emotions and memory. In addition, the paper will also present the serendipitous clinical observations (inductive research) and fortuitous inter-disciplinary collaborations that were crucial in guiding and developing the deductive research processes that culminated in the concept that primary emotions and related display behaviors are a lateralized function of the right hemisphere and social emotions, and related display behaviors are a lateralized function of the left hemisphere.

Differential Hemispheric Lateralization of Emotions and Related Display Behaviors: Emotion-Type Hypothesis.

There are two well-known hypotheses regarding hemispheric lateralization of emotions. The Right Hemisphere Hypothesis (RHH) postulates that emotions and associated display behaviors are a dominant and lateralized function of the right hemisphere. The Valence Hypothesis (VH) posits that negative emotions and related display behaviors are modulated by the right hemisphere and positive emotions and related display behaviors are modulated by the left hemisphere. Although both the RHH and VH are supported by extensive research data, they are mutually exclusive, suggesting that there may be a missing factor in play that may provide a more accurate description of how emotions are lateralization in the brain. Evidence will be presented that provides a much broader perspective of emotions by embracing the concept that emotions can be classified into primary and social types and that hemispheric lateralization is better explained by the Emotion-type Hypothesis (ETH). The ETH posits that primary emotions and related display behaviors are modulated by the right hemisphere and social emotions and related display behaviors are modulated by the left hemisphere.

Disorders of vocal emotional expression and comprehension: The aprosodias.

Language is traditionally considered to be a dominant function of the left hemisphere because of its role in modulating the propositional or literal aspects of language (what is said). This chapter, however, will address the vital role of the right hemisphere in modulating the nonverbal, affective-prosodic aspects of speech (how it is said) that are essential for appropriate interpersonal interactions, communication competency, and psychosocial well-being. Focal right hemisphere lesions cause various disorders of affective prosody (aprosodic syndromes) that are analogous to the various aphasic syndromes that occur following focal left hemisphere lesions. Disorders of affective prosody may present clinically as loss of psychosocial well-being with disruption of interpersonal relationships. This chapter will review the research published over the last four decades that has helped to elucidate the neurobiology of affective prosody and the pathophysiology underlying the aprosodic syndromes.

Deficits in affective prosody comprehension: family history of alcoholism versus alcohol exposure.

BACKGROUND: Abstinent alcoholics have deficits in comprehending the affective intonation in speech. Prior work suggests that these deficits are due to alcohol exposure rather than preexisting risk factors for alcoholism. The present paper examines whether family history of alcoholism is a contributor to affective prosody deficits in alcoholics. METHODS: Fifty-eight healthy, nonabusing young adults with and without a family history of alcoholism or other substance abuse (29 FH+ and 29 FH-) were compared on affective prosody comprehension using the Aprosodia Battery. A secondary analysis was done comparing affective prosody comprehension in FH+ and FH- detoxified alcoholics from an earlier study (17 FH+ and 14 FH-). RESULTS: Performance on the Aprosodia Battery was not related to FH status in either the healthy, nonabusing sample or in the detoxified alcoholic group. CONCLUSIONS: The present study lends support to previous research suggesting that deficits in affective prosody comprehension observed in detoxified alcoholics are associated with a history of heavy drinking rather than with a family history of alcoholism.

Differences in coated-platelet production between frontotemporal dementia and Alzheimer disease.

OBJECTIVE: Coated-platelets are a subset of platelets produced by dual-agonist activation with collagen and thrombin. These platelets retain full-length amyloid precursor protein on their surface and correlate inversely with disease severity in Alzheimer disease (AD). We have now investigated coated-platelet production and its relationship with disease severity in frontotemporal dementia (FTD) patients to determine whether our earlier observations were unique to AD. METHODS: Coated-platelet levels were assayed in 40 FTD, 40 AD patients, and 40 controls. Both patient groups were equally divided between mild-stage (Clinical Dementia Rating < or =1) and advanced stage dementia (Clinical Dementia Rating >1). RESULTS: Coated-platelet levels were not significantly different between patients with early-stage and advanced stage FTD (P=0.9), whereas early-stage AD patients had significantly higher levels than advanced stage AD (P<0.001). In addition, coated-platelet production was significantly elevated in early-stage AD versus early-stage FTD patients (P=0.01). CONCLUSIONS: In contrast to AD, there is no significant relationship between disease severity and coated-platelet levels in FTD. Differences in coated-platelet levels between early-stage AD and early-stage FTD patients warrant further investigation for potential clinical applications in helping to differentiate between these 2 disorders.

Comprehension of affective prosody in veterans with chronic posttraumatic stress disorder.

Posttraumatic stress disorder (PTSD) is one of the few psychiatric conditions in which a subjective decrease in emotional range serves as a diagnostic criterion. In order to investigate whether veterans with chronic PTSD also experienced objective limitations in emotional perception, the authors administered the Aprosodia Battery to a group of 11 veterans with chronic PTSD, nine subjects with right hemisphere damage, seven subjects with left hemisphere damage, and 12 comparison subjects. The patients with PTSD displayed significant deficiencies in the comprehension and discriminative components of affective speech, similar in severity and performance profile on the Aprosodia Battery to the individuals with focal right hemisphere damage due to ischemic infarction.

Neurophysiology of spontaneous facial expressions: II. Motor control of the right and left face is partially independent in adults.

Facial expressions are described traditionally as monolithic or unitary entities. However, humans have the capacity to produce facial blends of emotion in which the upper and lower face simultaneously display different expressions. Recent neuroanatomical studies in monkeys have demonstrated that there are separate cortical motor areas for controlling the upper and lower face in each hemisphere that, presumably, also occur in humans. Using high-speed videography, we began measuring the movement dynamics of spontaneous facial expressions, including facial blends, to develop a more complete understanding of the neurophysiology underlying facial expressions. In our part 1 publication in Cortex (2016), we found that hemispheric motor control of the upper and lower face is overwhelmingly independent; 242 (99%) of the expressions were classified as demonstrating independent hemispheric motor control whereas only 3 (1%) were classified as demonstrating dependent hemispheric motor control. In this companion paper (part 2), 251 unitary facial expressions that occurred on either the upper or lower face were analyzed. 164 (65%) expressions demonstrated dependent hemispheric motor control whereas 87 (35%) expressions demonstrated independent or dual hemispheric motor control, indicating that some expressions represent facial blends of emotion that occur across the vertical facial axis. These findings also support the concepts that 1) spontaneous facial expressions are organized predominantly across the horizontal facial axis and secondarily across the vertical facial axis and 2) facial expressions are complex, multi-component, motoric events. Based on the Emotion-type hypothesis of cerebral lateralization, we propose that facial expressions modulated by a primary-emotional response to an environmental event are initiated by the right hemisphere on the left side of the face whereas facial expressions modulated by a social-emotional response to an environmental event are initiated by the left hemisphere on the right side of the face.

Interpersonal prosodic correlation in frontotemporal dementia.

Communication accommodation describes how individuals adjust their communicative style to that of their conversational partner. We predicted that interpersonal prosodic correlation related to pitch and timing would be decreased in behavioral variant frontotemporal dementia (bvFTD). We predicted that the interpersonal correlation in a timing measure and a pitch measure would be increased in right temporal FTD (rtFTD) due to sparing of the neural substrate for speech timing and pitch modulation but loss of social semantics. We found no significant effects in bvFTD, but conversations including rtFTD demonstrated higher interpersonal correlations in speech rate than healthy controls.

fMRI evidence for the effect of verbal complexity on lateralisation of the neural response associated with decoding prosodic emotion.

The pattern of intonation accompanying an utterance provides a powerful cue as to a speaker's emotional state of mind. Most prior lesion studies have demonstrated that the nodal point for decoding these prosodic emotion cues is mediated by unimodal auditory cortex in the right posterior lateral temporal lobe. However, functional neuroimaging has brought with it increasing attention to the equivalent left hemisphere region in this role. This study used fMRI to quantitatively assess the hypothesis that involvement of the left posterior lateral temporal lobe depended on the linguistic load or verbal complexity of the prosodic emotion stimuli. BOLD contrast data was acquired on a 3T scanner whilst 16 healthy young adults identified the prosodic emotion in three conditions: 'sentences' comprised of words, a repeated monosyllable, and a single prolonged syllable (asyllabic). Whole-brain analyses were performed using SPM5 and supplemented by posterior lateral temporal lobe region of interest (ROI) analyses. The whole-brain analyses appeared to show bilateral temporal lobe activation across the conditions, however, the ROI analyses indicated a highly significant decrease in activity in the left ROI as verbal complexity decreased. Changes in right ROI activity were not statistically significant. Our results indicate that the likelihood of observing a notable left temporal lobe response in functional neuroimaging studies of emotional prosody comprehension depends on the verbal complexity of the prosodic emotion stimuli. Despite the right hemisphere dominance underlying this task, the left hemisphere region may be co-activated in its attempt to extract phonetic-segmental information from the acoustic stimuli whether or not the stimuli contain meaningful phonetic-segmental information.

Sensory-specific amnesia and hypoemotionality in humans and monkeys: gateway for developing a hodology of memory.

Amnesia is a dramatic clinical syndrome caused by diverse pathologies and lesion localizations. Although amnesia is typically screened for by clinicians using verbal stimuli, amnestic syndromes have been described that do not impair verbal memory and may be confined to a single sensory system or a dominant or highly lateralized sensory function. Thus, the functional-anatomic basis for various types of amnestic disorders is complex and, in most instances, better understood as a disconnection syndrome rather than a primary processing deficit. Using the clinical disorder of sensory-specific visual amnesia in humans as a springboard, a hodological model for understanding the various types of amnestic syndromes encountered in the clinic and those produced by discrete experimental lesions in monkeys is offered. The model is then expanded to encompass memory functions, in general, including agnostic deficits and the role of prefrontal cortex in learning and remembering.

Neurology of affective prosody and its functional-anatomic organization in right hemisphere.

Unlike the aphasic syndromes, the organization of affective prosody in brain has remained controversial because affective-prosodic deficits may occur after left or right brain damage. However, different patterns of deficits are observed following left and right brain damage that suggest affective prosody is a dominant and lateralized function of the right hemisphere. Using the Aprosodia Battery, which was developed to differentiate left and right hemisphere patterns of affective-prosodic deficits, functional-anatomic evidence is presented in patients with focal ischemic strokes to support the concepts that (1) affective prosody is a dominant and lateralized function of the right hemisphere, (2) the intrahemispheric organization of affective prosody in the right hemisphere, with the partial exception of Repetition, is analogous to the organization of propositional language in the left hemisphere and (3) the aprosodic syndromes are cortically based as part of evolutionary adaptations underlying human language and communication.

Human facial expressions are organized functionally across the upper-lower facial axis.

Most clinical research has focused on intensity differences of facial expressions between the right and left hemiface to explore lateralization of emotions in the brain. Observations by social psychologists, however, suggest that control of facial expression is organized predominantly across the upper-lower facial axis because of the phenomena of facial blends: simultaneous display of different emotions on the upper and lower face. Facial blends are related to social emotions and development of display rules that allow individuals to sculpt facial expressions for social and manipulative purposes. We have demonstrated that facial blends of emotion are more easily and accurately posed on the upper-lower than right-left hemiface, and that upper facial emotions are processed preferentially by the right hemisphere whereas lower facial emotions are processed preferentially by the left hemisphere. Based on these results, recent anatomical studies showing separate cortical areas for motor control of upper and lower face and the neurology of posed and spontaneous expressions of emotion, a functional-anatomic model of how the forebrain modulates facial expressions, is presented. The unique human ability to produce facial blends of emotion is, most likely, an adaptive modification linked to the evolution of speech and language.

Processing of facial blends of emotion: support for right hemisphere cognitive aging.

Clinical research on facial emotions has focused primarily on differences between right and left hemiface. Social psychology, however, has suggested that differences between upper versus lower facial displays may be more important, especially during social interactions. We demonstrated previously that upper facial displays are perceived preferentially by the right hemisphere, while lower facial displays are perceived preferentially by the left hemisphere. A marginal age-related effect was observed. The current research expands our original cohort to include 26 elderly individuals over age 62. Fifty-six, strongly right-handed, healthy, adult volunteers were tested tachistoscopically by flashing randomized facial displays of emotion to the right and left visual fields. The stimuli consisted of line drawings displaying various combinations of emotions on the upper and lower face. The subjects were tested under two conditions: without attend instruction and with instructions to attend to the upper face. Based on linear regression and discriminant analyses modeling age, subject performance could be divided into two distinct groups: Young (< 62 years) and Old (> 62 years). Without attend instructions, both groups robustly identified the emotion displayed on the lower face, regardless of visual field presentation. With instructions to attend to the upper face, the Old group demonstrated a markedly decreased ability to identify upper facial displays, compared to the Young group. The most significant difference was noted in the left visual field/right hemisphere. Our results demonstrate a significant decline in the processing of upper facial emotions by the right hemisphere in older individuals, thus providing partial support for the right hemisphere hypothesis of cognitive aging. The decreased ability to perceive upper facial displays coupled with age-related deficits in processing affective prosody may well cause impaired psychosocial competency in the elderly.

Facial expressions are more easily produced on the upper-lower compared to the right-left hemiface.

Clinical research has concentrated on differences in intensity of expression between the right and left hemiface as a means to assess hemispheric differences in motor control. However, observations by social psychologists suggest that control of facial expression may be organized predominantly across the upper-lower hemiface because during social interactions individuals may produce brief facial blends of emotions, in which the upper and lower face display a different emotion. Full facial versus upper/lower and right/left facial blends of emotion were posed by 20 subjects, 10 men and 10 women ranging in age from 20 to 37 years. The subjects rated the difficulty of each pose on a 5-point Likert scale. Digital photographs of the poses were taken and the full and half-facial poses were shown in random order to four judges who indicated what pose was being performed. The results were very robust and confirmed that facial blends of emotion are more easily and accurately posed on the upper-lower than on the right-left hemiface. Our results are consistent with recent anatomical studies showing separate cortical areas for motor control of the upper versus lower face in primates. Based on recent research exploring hemispheric differences in perceiving facial blends of emotion, the left hemisphere may be more involved with modulating lower facial expressions and the right hemisphere more involved with modulating upper facial expressions.

Altered saccadic targets when processing facial expressions under different attentional and stimulus conditions.

Depending on a subject's attentional bias, robust changes in emotional perception occur when facial blends (different emotions expressed on upper/lower face) are presented tachistoscopically. If no instructions are given, subjects overwhelmingly identify the lower facial expression when blends are presented to either visual field. If asked to attend to the upper face, subjects overwhelmingly identify the upper facial expression in the left visual field but remain slightly biased to the lower facial expression in the right visual field. The current investigation sought to determine whether differences in initial saccadic targets could help explain the perceptual biases described above. Ten subjects were presented with full and blend facial expressions under different attentional conditions. No saccadic differences were found for left versus right visual field presentations or for full facial versus blend stimuli. When asked to identify the presented emotion, saccades were directed to the lower face. When asked to attend to the upper face, saccades were directed to the upper face. When asked to attend to the upper face and try to identify the emotion, saccades were directed to the upper face but to a lesser degree. Thus, saccadic behavior supports the concept that there are cognitive-attentional pre-attunements when subjects visually process facial expressions. However, these pre-attunements do not fully explain the perceptual superiority of the left visual field for identifying the upper facial expression when facial blends are presented tachistoscopically. Hence other perceptual factors must be in play, such as the phenomenon of virtual scanning.

Neurophysiology of spontaneous facial expressions: I. Motor control of the upper and lower face is behaviorally independent in adults.

Facial expressions are described traditionally as monolithic entities. However, humans have the capacity to produce facial blends, in which the upper and lower face simultaneously display different emotional expressions. This, in turn, has led to the Component Theory of facial expressions. Recent neuroanatomical studies in monkeys have demonstrated that there are separate cortical motor areas for controlling the upper and lower face that, presumably, also occur in humans. The lower face is represented on the posterior ventrolateral surface of the frontal lobes in the primary motor and premotor cortices and the upper face is represented on the medial surface of the posterior frontal lobes in the supplementary motor and anterior cingulate cortices. Our laboratory has been engaged in a series of studies exploring the perception and production of facial blends. Using high-speed videography, we began measuring the temporal aspects of facial expressions to develop a more complete understanding of the neurophysiology underlying facial expressions and facial blends. The goal of the research presented here was to determine if spontaneous facial expressions in adults are predominantly monolithic or exhibit independent motor control of the upper and lower face. We found that spontaneous facial expressions are very complex and that the motor control of the upper and lower face is overwhelmingly independent, thus robustly supporting the Component Theory of facial expressions. Seemingly monolithic expressions, be they full facial or facial blends, are most likely the result of a timing coincident rather than a synchronous coordination between the ventrolateral and medial cortical motor areas responsible for controlling the lower and upper face, respectively. In addition, we found evidence that the right and left face may also exhibit independent motor control, thus supporting the concept that spontaneous facial expressions are organized predominantly across the horizontal facial axis and secondarily across the vertical axis.

Impaired comprehension of affective prosody in elderly subjects is not predicted by age-related hearing loss or age-related cognitive decline.

Impairments in the ability of elderly people to comprehend affective prosody have been reported, but little is known about the relationship between affective prosodic comprehension and age-related changes in hearing and cognition. The Aprosodia Battery, which included an assessment of attitudinal comprehension, was used to compare affective-prosodic comprehension in young and elderly subjects and to investigate the relationship of results to selected hearing and neuropsychological measures. As a group, the healthy elderly subjects were impaired relative to young subjects on all tasks assessing comprehension of affective prosody. Variability within the elderly group was not predicted by mild to moderate peripheral hearing loss and was only marginally predicted by traditional cognitive measures. These findings along with those of other researchers suggest that loss of affective-prosodic comprehension in elderly persons is related to a specific aging effect that impairs right hemisphere function.

Postural instability in Parkinson Disease: to step or not to step.

Postural instability is a key feature of Parkinson Disease that is associated with falls and morbidity. We designed a pull apparatus to quantitatively measure the force needed to pull subjects off-balance. Thirteen Controls and eight individuals with Parkinson Disease (PD) were evaluated. All individuals with PD reported subjective symptoms of postural instability and were symptomatic for approximately 9.4years when tested. No significant differences were found between Controls and PD subjects in the magnitude of force required to pull them off-balance. None of the Controls fell and all took a step into the direction of pull to maintain their balance. 59% of the time PD subjects fell because they did not take a step in the direction of pull to maintain their center of mass (COM) over their feet, thus indicating a deficiency in postural reflexes. If they fell on the first pull, PD subjects did not show a learning effect when pulled multiple times in the same direction. The utility of the Pull Test to detect postural instability is related to the subject's behavioral response, not the force needed to pull them off balance. Our findings may also help explain certain features of the PD gait as an attempt by subjects to avoid postural instability by not placing their COM in gravitationally unstable positions.