Contemporary Dance Practice Improves Motor Function and Body Representation in Huntington's Disease: A Pilot Study.

BACKGROUND: Physical exercise improves neurological conditions, but adherence is hard to establish. Dance might be a promising alternative; however, since patients with Huntington's disease (HD) suffer from rhythmic movement execution deficits, any metric dance practice must be avoided. OBJECTIVE: Here we asked, if contemporary dance, a lyrical dance form, practiced for two hours per week over five months, might improve motor function, neuropsychiatric variables, cognition and brain volume of HD patients. METHODS: Nineteen patients aged between 43 and 78 years with mild to moderate HD (TFC range 7-13, UHDRS motor score range 3-58) participated in this randomized, controlled pilot study (NCT 01842919). The primary outcome measure was total motor score. Secondary outcome measures were differences in brain structure, cognitive function, neuropsychiatric variables, apathy and quality of life. A semi-structured interview assessed participants' experiences. RESULTS: Adherence to dance classes was very good. All participants completed 5 months of dance practice. Motor impairment (median [IQR] decreased from 28[6-51] to 27[7-33] for the dance group compared to an increase of 19[13-35] - 25[14-42] for usual care, Z = -2.44, p = 0.015). No other behavioral measures showed any changes.Brain volume increased in the medial superior parietal and paracentral lobule, in line with compensatory structural brain changes in areas supporting spatial and somatosensory processing. These changes were also reflected in patients' reports that contemporary dance altered the way they "felt and lived in their bodies". CONCLUSIONS: Contemporary dance practice, through work on spatial and bodily representations, helps improve motor function in HD patients.

Embodied emotion impairment in Huntington's Disease.

Theories of embodied cognition suggest that perceiving an emotion involves somatovisceral and motoric re-experiencing. Here we suggest taking such an embodied stance when looking at emotion processing deficits in patients with Huntington's Disease (HD), a neurodegenerative motor disorder. The literature on these patients' emotion recognition deficit has recently been enriched by some reports of impaired emotion expression. The goal of the study was to find out if expression deficits might be linked to a more motoric level of impairment. We used electromyography (EMG) to compare voluntary emotion expression from words to emotion imitation from static face images, and spontaneous emotion mimicry in 28 HD patients and 24 matched controls. For the latter two imitation conditions, an underlying emotion understanding is not imperative (even though performance might be helped by it). EMG measures were compared to emotion recognition and to the capacity to identify and describe emotions using alexithymia questionnaires. Alexithymia questionnaires tap into the more somato-visceral or interoceptive aspects of emotion perception. Furthermore, we correlated patients' expression and recognition scores to cerebral grey matter volume using voxel-based morphometry (VBM). EMG results replicated impaired voluntary emotion expression in HD. Critically, voluntary imitation and spontaneous mimicry were equally impaired and correlated with impaired recognition. By contrast, alexithymia scores were normal, suggesting that emotion representations on the level of internal experience might be spared. Recognition correlated with brain volume in the caudate as well as in areas previously associated with shared action representations, namely somatosensory, posterior parietal, posterior superior temporal sulcus (pSTS) and subcentral sulcus. Together, these findings indicate that in these patients emotion deficits might be tied to the "motoric level" of emotion expression. Such a double-sided recognition and expression impairment may have important consequences, interrupting empathy in nonverbal communication both ways (understanding and being understood), independently of intact internal experience of emotion.

Joint recognition-expression impairment of facial emotions in Huntington's disease despite intact understanding of feelings.

Patients with Huntington's disease (HD), a neurodegenerative disorder that causes major motor impairments, also show cognitive and emotional deficits. While their deficit in recognising emotions has been explored in depth, little is known about their ability to express emotions and understand their feelings. If these faculties were impaired, patients might not only mis-read emotion expressions in others but their own emotions might be mis-interpreted by others as well, or thirdly, they might have difficulties understanding and describing their feelings. We compared the performance of recognition and expression of facial emotions in 13 HD patients with mild motor impairments but without significant bucco-facial abnormalities, and 13 controls matched for age and education. Emotion recognition was investigated in a forced-choice recognition test (FCR), and emotion expression by filming participants while they mimed the six basic emotional facial expressions (anger, disgust, fear, surprise, sadness and joy) to the experimenter. The films were then segmented into 60 stimuli per participant and four external raters performed a FCR on this material. Further, we tested understanding of feelings in self (alexithymia) and others (empathy) using questionnaires. Both recognition and expression were impaired across different emotions in HD compared to controls and recognition and expression scores were correlated. By contrast, alexithymia and empathy scores were very similar in HD and controls. This might suggest that emotion deficits in HD might be tied to the expression itself. Because similar emotion recognition-expression deficits are also found in Parkinson's Disease and vascular lesions of the striatum, our results further confirm the importance of the striatum for emotion recognition and expression, while access to the meaning of feelings relies on a different brain network, and is spared in HD.

Viewing another person's body as a target object: a behavioural and PET study of pointing.

Humans usually point at objects to communicate with other persons, although they generally avoid pointing at the other's body. Moreover, patients with heterotopagnosia after left parietal damage cannot point at another person's body parts, although they can point at objects and at their own body parts and although they can grasp the others' body parts. Strikingly, their performance gradually improves for figurative human body targets. Altogether, this suggests that the body of another real person holds a specific status in communicative pointing. Here, we test in healthy individuals whether performance for communicative pointing is influenced by the communicative capacity of the target. In Experiment 1, pointing at another real person's body parts was compared to pointing at objects, and in Experiment 2, the person was replaced by a manikin. While reaction times for pointing at objects were shorter compared to pointing at other person's body parts, they were similar for objects and manikin body parts. By adapting Experiment 1 to PET-scan imaging (Experiment 3), we showed that, compared to pointing at objects, the brain network for pointing at other person's body parts involves the left posterior intraparietal sulcus, lesion of which could cause heterotopagnosia. Taken together, our results indicate that the specificity of pointing at another person's body goes beyond the visuo-spatial features of the human body and might rather rely on its communicative capacity.

Feeling of presence in Parkinson's disease.

BACKGROUND: A feeling of presence (FP), that is, the vivid sensation that somebody (distinct from oneself) is present nearby, is commonly reported by patients with Parkinson's disease (PD), but its phenomenology has not been described precisely. The objective of this study was to provide a detailed description of FP in PD and to discuss its possible mechanisms. PATIENTS AND METHODS: The authors studied 52 non-demented PD patients reporting FP in the preceding month (38 consecutive outpatients and 14 inpatients). FP characteristics were recorded with a structured questionnaire. The outpatients with FP were compared with 78 consecutive outpatients without FP. RESULTS: About half the patients said they recognised the 'identity' of the presence. More than 75% of patients said the FP were not distressing, were short-lasting, were felt beside and/or behind the patient, and occurred while indoors; most patients checked for a real presence, but their insight was generally preserved. In 31% of cases, the patients had an unformed visual hallucination simultaneously with the FP. A higher daily levodopa-equivalent dose and the presence of visual illusions or hallucinations were independently associated with FP. DISCUSSION: Although FP is not a sensory perception, projection of the sensation into the extrapersonal space, along with the frequent co-occurrence of elementary visual hallucinations and the strong association with visual hallucinations or illusions, supports its hallucinatory nature. FP may be viewed as a 'social' hallucination, involving an area or network specifically activated when a living being is present, independently of any perceptual clue.

The impairment of emotion recognition in Huntington's disease extends to positive emotions.

Patients with Huntington's Disease (HD) are impaired in the recognition of emotional signals. However, the nature and extent of the impairment is controversial: it has variously been argued to disproportionately affect disgust (e.g., Sprengelmeyer et al., 1996), to be general for negative emotions (Snowden et al., 2008), or to be a consequence of item difficulty (Milders et al., 2003). Yet no study to date has included more than one positive stimulus category in emotion recognition tasks, and most studies have focused on the recognition of emotions from facial stimuli. In this study, we test the hypothesis that patients with HD may be impaired in their recognition of positive as well as negative emotional signals, by examining the recognition of a range of positive emotions from vocal cues. We present a study of 14 Huntington's patients and 15 controls performing a forced-choice task with a previously validated set of negative and positive non-verbal emotional vocalizations (Sauter and Scott, 2007). Although HD patients performed above chance for each emotion, they were found to be impaired in both positive and negative emotions, including pleasure, fear and anger. These findings complement previous work by demonstrating that impairments in emotion recognition in HD extend to positive and negative emotions, which may imply a general deficit.

Behavioral and neural correlates of communication via pointing.

Communicative pointing is a human specific gesture which allows sharing information about a visual item with another person. It sets up a three-way relationship between a subject who points, an addressee and an object. Yet psychophysical and neuroimaging studies have focused on non-communicative pointing, which implies a two-way relationship between a subject and an object without the involvement of an addressee, and makes such gesture comparable to touching or grasping. Thus, experimental data on the communicating function of pointing remain scarce. Here, we examine whether the communicative value of pointing modifies both its behavioral and neural correlates by comparing pointing with or without communication. We found that when healthy participants pointed repeatedly at the same object, the communicative interaction with an addressee induced a spatial reshaping of both the pointing trajectories and the endpoint variability. Our finding supports the hypothesis that a change in reference frame occurs when pointing conveys a communicative intention. In addition, measurement of regional cerebral blood flow using H(2)O(15) PET-scan showed that pointing when communicating with an addressee activated the right posterior superior temporal sulcus and the right medial prefrontal cortex, in contrast to pointing without communication. Such a right hemisphere network suggests that the communicative value of pointing is related to processes involved in taking another person's perspective. This study brings to light the need for future studies on communicative pointing and its neural correlates by unraveling the three-way relationship between subject, object and an addressee.

Heterotopagnosia: When I point at parts of your body.

Heterotopagnosia is the acquired inability of brain-lesioned patients to point at someone else's body parts when prompted. The cognitive basis of this disorder is unclear. It might result from a biological function deficit critical for communication in human beings; alternatively, it could result from the disruption of a body representation. Here, we report three patients with heterotopagnosia following a recent left parieto-occipital stroke and a previous insular lesion. The patients were tested on their ability to name, point out and grasp several targets including body parts (own, real others' and figurative others'). Language, visuo-spatial deficits or any confounding neuropsychological disorders were controlled for. We found that the patients erroneously pointed to their own body parts when asked to point at someone else's. Strikingly, their ability to grasp someone else's body parts was largely unimpaired. The dissociation between their grasping and communicative pointing abilities supports the hypothesis that heterotopagnosia is a disorder of communicative function conveyed by pointing but not by grasping. In addition, pointing performance in our patients varied according to the target: the more similar the target was to a real person, the worse the patients' pointing performance. We suggest that communicative pointing might require a specific representation of the addressee's body and point of view, a heterocentric representation. In the patients described here this phenomenon resulted from a combined insulo-parietal lesion, which may explain why, in contrast to other patients described previously, the heterotopagnosia was long-lasting.

Neural bases of autobiographical support for episodic recollection of faces.

Incidental retrieval of autobiographical knowledge can provide rich contextual support for episodic recollection of a recent event. We examined the neural bases of these two processes by performing fMRI scanning during a recognition memory test for faces that were unfamiliar, famous, or personally known. The presence of pre-experimental knowledge of a face was incidental to the task, but nonetheless resulted in improved performance. Two distinct networks of activation were associated with correct recollection of a face's prior presentation (recollection hits vs. correct rejections) on one hand, and with pre-experimental knowledge about it (famous or personally known vs. unfamiliar faces) on the other. The former included mid/posterior cingulate cortex, precuneus, and ventral striatum. The latter included bilateral hippocampus, retrosplenial, and ventromedial prefrontal cortices. Anterior and medial thalamic activations showed an interaction between both effects, driven by increased activation for recollection of unfamiliar faces. When recollecting the presentation of a famous or personally known face, hippocampal activation increased with participants' ratings of how well they felt they knew the person shown. Ventromedial prefrontal cortex showed significantly greater activation for personally known than famous faces. Our results indicate a dissociation between the involvement of retrosplenial vs. mid/posterior cingulate and precuneus in memory tasks. They also indicate that, during recognition memory experiments, the hippocampus supports incidental retrieval of pre-experimental knowledge about the stimuli presented. This type of knowledge likely underlies the additional recollection found for prior presentation of well known stimuli compared with novel ones and may link hippocampal activation at encoding to subsequent memory performance more generally.

Impaired allocentric spatial memory underlying topographical disorientation.

The cognitive processes supporting spatial navigation are considered in the context of a patient (CF) with possible very early Alzheimer's disease who presents with topographical disorientation. Her verbal memory and her recognition memory for unknown buildings, landmarks and outdoor scenes was intact, although she showed an impairment in face processing. By contrast, her navigational ability, quantitatively assessed within a small virtual reality (VR) town, was significantly impaired. Interestingly, she showed a selective impairment in a VR object-location memory test whenever her viewpoint was shifted between presentation and test, but not when tested from the same viewpoint. We suggest that a specific impairment in locating objects relative to the environment rather than relative to the perceived viewpoint (i.e. allocentric rather than egocentric spatial memory) underlies her topographical disorientation. We discuss the likely neural bases of this deficit in the light of related studies in humans and animals, focusing on the hippocampus and related areas. The specificity of our test indicates a new way of assessing topographical disorientation, with possible application to the assessment of progressive dementias such as Alzheimer's disease.

Geometric determinants of human spatial memory.

Geometric alterations to the boundaries of a virtual environment were used to investigate the representations underlying human spatial memory. Subjects encountered a cue object in a simple rectangular enclosure, with distant landmarks for orientation. After a brief delay, during which they were removed from the arena, subjects were returned to it at a new location and orientation and asked to mark the place where the cue had been. On some trials the geometry (size, aspect ratio) of the arena was varied between presentation and testing. Responses tended to lie somewhere between a location that maintained fixed distances from nearby walls and a location that maintained fixed ratios of the distances between opposing walls. The former were more common after expansions and for cued locations nearer to the edge while the latter were more common after contractions and for locations nearer to the center. The spatial distributions of responses predicted by various simple geometric models were compared to the data. The best fitting model was one derived from the response properties of 'place cells' in the rat hippocampus, which matches the 'proximities' 1/(d+c) of the cue to the four walls of the arena, where d is the distance to a wall and c is a global constant. Subjects also tended to adopt the same orientation at presentation and testing, although this was not due to using a view matching strategy, which could be ruled out in 50% of responses. Disoriented responses were most often seen where the cued location was near the center of the arena or where the long axis of a rectangular arena was changed between presentation and testing, suggesting that the geometry of the arena acts as a weak cue to orientation. Overall, the results suggest a process of visual landmark matching to determine orientation, combined with an abstract representation of the proximity of the cued location to the walls of the arena consistent with the neural representation of location in the hippocampus.

The hippocampal role in spatial memory and the familiarity--recollection distinction: a case study.

Memory for object locations and for events (comprising the receipt of an object) was tested in a case of developmental amnesia with focal hippocampal damage. Tests used virtual reality environments and forced-choice recognition with foils chosen to equalize the performance of control participants across conditions. Memory for the objects received was unimpaired, but the context of their receipt was forgotten. Memory for short lists of object locations was unimpaired when tested from the same viewpoint as presentation but impaired when tested from a shifted viewpoint. Same-view performance was disrupted by changing the background scene. These results are consistent with Jon having preserved matching to fixed sensory-bound representations but impaired reconstructed or manipulable representations underlying shifted-viewpoint recognition and episodic recollection.