Musical alexia with recovery: a personal account

Four Social Brain Regions, Their Dysfunctions, and Sequelae, Extensively Explain Autism Spectrum Disorder Symptomatology

Autism spectrum disorder (ASD) is a challenging neurodevelopmental disorder with symptoms in social, language, sensory, motor, cognitive, emotional, repetitive behavior, and self-sufficient living domains. The important research question examined is the elucidation of the pathogenic neurocircuitry that underlies ASD symptomatology in all its richness and heterogeneity. The presented model builds on earlier social brain research, and hypothesizes that four social brain regions largely drive ASD symptomatology: amygdala, orbitofrontal cortex (OFC), temporoparietal cortex (TPC), and insula. The amygdala's contributions to ASD largely derive from its major involvement in fine-grained intangible knowledge representations and high-level guidance of gaze. In addition, disrupted brain regions can drive disturbance of strongly interconnected brain regions to produce further symptoms. These and related effects are proposed to underlie abnormalities of the visual cortex, inferior frontal gyrus (IFG), caudate nucleus, and hippocampus as well as associated symptoms. The model is supported by neuroimaging, neuropsychological, neuroanatomical, cellular, physiological, and behavioral evidence. Collectively, the model proposes a novel, parsimonious, and empirically testable account of the pathogenic neurocircuitry of ASD, an extensive account of its symptomatology, a novel physiological biomarker with potential for earlier diagnosis, and novel experiments to further elucidate the mechanisms of brain abnormalities and symptomatology in ASD.

Uncommon and/or bizarre features of dementia: Part III

Clinical neurologists have long recognized that dementia can present as atypical or variant syndromes/symptoms. This study aimed at describing uncommon or bizarre symptoms/syndromes observed in patients suffering from dementia. Medline and Google scholar searches were conducted for relevant articles, chapters, and books published before 2018. Search terms used included compulsion, dementia, extracampine hallucination, disordered gambling, humour, and obsession. Publications found through this indexed search were reviewed for further relevant references. The uncommon/bizarre feature of dementia was described as case reports and there were no systematic investigations.

Oliver Sacks and migraine

Background

Oliver Sacks (1933–2015) published a large number of books on a variety of neurological topics. Of these, numerous copies have been sold and they probably serve as the only or main source of information on neurological diseases for many persons without a medical background. His first book was on migraine and in his subsequent books many descriptions of migraine can be found, mainly those of auras.

Methods

We explored the descriptions of migraine in Sacks’ work in order to evaluate the image of migraine offered to the readers.

Conclusion

Oliver Sacks gave wonderful descriptions of migraine auras, but hardly any of migraine headache. Furthermore, he described rare auras such as ‘amusia’ and olfactory auras. Overall, this makes his descriptions of migraine not very useful to serve as medical information for laypersons. Oliver Sacks, however, wrote great literature.

Music Perception in Dementia

Despite much recent interest in music and dementia, music perception has not been widely studied across dementia syndromes using an information processing approach. Here we addressed this issue in a cohort of 30 patients representing major dementia syndromes of typical Alzheimer's disease (AD, n = 16), logopenic aphasia (LPA, an Alzheimer variant syndrome; n = 5), and progressive nonfluent aphasia (PNFA; n = 9) in relation to 19 healthy age-matched individuals. We designed a novel neuropsychological battery to assess perception of musical patterns in the dimensions of pitch and temporal information (requiring detection of notes that deviated from the established pattern based on local or global sequence features) and musical scene analysis (requiring detection of a familiar tune within polyphonic harmony). Performance on these tests was referenced to generic auditory (timbral) deviance detection and recognition of familiar tunes and adjusted for general auditory working memory performance. Relative to healthy controls, patients with AD and LPA had group-level deficits of global pitch (melody contour) processing while patients with PNFA as a group had deficits of local (interval) as well as global pitch processing. There was substantial individual variation within syndromic groups. Taking working memory performance into account, no specific deficits of musical temporal processing, timbre processing, musical scene analysis, or tune recognition were identified. The findings suggest that particular aspects of music perception such as pitch pattern analysis may open a window on the processing of information streams in major dementia syndromes. The potential selectivity of musical deficits for particular dementia syndromes and particular dimensions of processing warrants further systematic investigation.

Brain disorders and the biological role of music

Despite its evident universality and high social value, the ultimate biological role of music and its connection to brain disorders remain poorly understood. Recent findings from basic neuroscience have shed fresh light on these old problems. New insights provided by clinical neuroscience concerning the effects of brain disorders promise to be particularly valuable in uncovering the underlying cognitive and neural architecture of music and for assessing candidate accounts of the biological role of music. Here we advance a new model of the biological role of music in human evolution and the link to brain disorders, drawing on diverse lines of evidence derived from comparative ethology, cognitive neuropsychology and neuroimaging studies in the normal and the disordered brain. We propose that music evolved from the call signals of our hominid ancestors as a means mentally to rehearse and predict potentially costly, affectively laden social routines in surrogate, coded, low-cost form: essentially, a mechanism for transforming emotional mental states efficiently and adaptively into social signals. This biological role of music has its legacy today in the disordered processing of music and mental states that characterizes certain developmental and acquired clinical syndromes of brain network disintegration.

Fifty Percent Prevalence of Extracampine Hallucinations in Parkinson's Disease Patients

Extracampine hallucinations (EH), the sense of a presence or fleeting movement in the absence of an associated visual percept, have been reported in Parkinson's disease (PD) patients but their prevalence, characteristics, and temporal relationship to visual hallucinations (VH) remain unclear. Given that, VH are predictive of cognitive impairment in PD, improved understanding of EH may have significant prognostic implications. The objective of this study is to evaluate the prevalence and characteristics of EH in a large unselected population with PD and to assess the temporal relationship between EH, VH, and memory decline. Cross-sectional data were collected from 414 PD patients using a questionnaire circulated via an online patient community. Data were obtained regarding the occurrence, timing, and characteristics of VH and EH and symptoms of PD, disease duration, disease severity, and medication history. About 50.4% of respondents reported EH and 15.5% reported VH. EH were typically experienced alongside, rather than behind, the individual (p < 0.001) without clear lateralization (p = 0.438) and were more likely to be of unfamiliar presences (p < 0.001). The occurrence of EH was associated with Hoehn and Yahr score (p = 0.002) but not disease duration (p = 0.158). EH onset was associated with VH onset (p = 0.046) and occurred after the onset of anosmia (p < 0.001), cognitive decline (p = 0.002), and sleep disturbance (p = 0.002). The reported prevalence of EH in PD patients was threefold greater than that of VH, with similar timings of onset, suggesting that EH are under-recognized and under-reported. Further work is needed to determine whether EH are predictive of cognitive decline.

Acquired amusia

Recent developments in the cognitive neuroscience of music suggest that a further review of the topic of amusia is timely. In this chapter, we first consider previous taxonomies of amusia and propose a fresh framework for understanding the amusias, essentially as disorders of cognitive information processing. We critically review current cognitive and neuroanatomic findings in the published literature on amusia. We assess the extent to which the clinical and neuropsychologic evidence in amusia can be reconciled; both with the information-processing framework we propose, and with the picture of the brain organization of music and language processing emerging from cognitive neuroscience and functional neuroimaging studies. The balance of evidence suggests that the amusias can be understood as disorders of musical object cognition targeting separable levels of an information-processing hierarchy and underpinned by specific brain network dysfunction. The neuroanatomic associations of the amusias show substantial overlap with brain networks that process speech; however, this convergence leaves scope for separable brain mechanisms based on altered connectivity and dynamics across culprit networks. The study of the amusias contributes to an increasingly complex picture of the musical brain that transcends any simple dichotomy between music and speech or other complex sounds.

Hallucinations of musical notation

Hallucinations of musical notation may occur in a variety of conditions, including Charles Bonnet syndrome, Parkinson's disease, fever, intoxications, hypnagogic and hypnopompic states. Eight cases are described here, and their possible cerebral mechanisms discussed.

The cognitive organization of music knowledge: a clinical analysis

Despite much recent interest in the clinical neuroscience of music processing, the cognitive organization of music as a domain of non-verbal knowledge has been little studied. Here we addressed this issue systematically in two expert musicians with clinical diagnoses of semantic dementia and Alzheimer’s disease, in comparison with a control group of healthy expert musicians. In a series of neuropsychological experiments, we investigated associative knowledge of musical compositions (musical objects), musical emotions, musical instruments (musical sources) and music notation (musical symbols). These aspects of music knowledge were assessed in relation to musical perceptual abilities and extra-musical neuropsychological functions. The patient with semantic dementia showed relatively preserved recognition of musical compositions and musical symbols despite severely impaired recognition of musical emotions and musical instruments from sound. In contrast, the patient with Alzheimer’s disease showed impaired recognition of compositions, with somewhat better recognition of composer and musical era, and impaired comprehension of musical symbols, but normal recognition of musical emotions and musical instruments from sound. The findings suggest that music knowledge is fractionated, and superordinate musical knowledge is relatively more robust than knowledge of particular music. We propose that music constitutes a distinct domain of non-verbal knowledge but shares certain cognitive organizational features with other brain knowledge systems. Within the domain of music knowledge, dissociable cognitive mechanisms process knowledge derived from physical sources and the knowledge of abstract musical entities.