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Neurology
Published in Kaji Sritharan, Jonathan Rohrer, Alexandra C Rankin, Sachi Sivananthan, Essential Notes for Medical and Surgical Finals, 2021
Kaji Sritharan, Jonathan Rohrer, Alexandra C Rankin, Sachi Sivananthan
This is a group of disorders characterised by frontal/temporal lobe atrophy, often with young onset (<65 years). There are three main syndromes: frontotemporal dementia – personality change/behavioural symptoms.semantic dementia – loss of semantic memory, i.e. conceptual knowledge.progressive non-fluent aphasia – impaired speech production.Other causes of dementia – it is important to rule out ‘reversible’ causesMetabolic: Vitamin B12/folate deficiency, hypothyroidism, Wilson’s diseaseInflammation/infection: HIV, multiple sclerosis, cerebral vasculitis, SLE, neurosyphilisDegenerative: Huntington’s disease, progressive supranuclear palsy, CJD Alcohol/toxicStructural: chronic subdural haematoma, tumours
Estrogens and dementia: a clinical and epidemiological update
Published in Barry G. Wren, Progress in the Management of the Menopause, 2020
The key symptom of Alzheimer’s disease is a defect in long-term episodic memory — the ability to learn new information that can be recalled after a delay of several minutes or longer. Although semantic memory — memory for over-learned general information such as word names — is also affected, a disturbance in semantic memory is usually not the initial symptom, and semantic memory is less severely disrupted early in the disease course. Episodic memory loss in Alzheimer’s disease is linked to severe pathological changes within hippocampal and parahippocampal structures of the medial temporal lobes1 and to a deficiency in the neurotransmitter acetylcholine2. Semantic memory loss reflects more widely distributed pathology within the association cortex of the cerebral hemispheres.Other cognitive and behavioral alterations are common in this illness. Visuospatial impairments, for example, are implied when patients become lost in their own home or are unable to copy simple line drawings3. A depressed mood4 and other behavioral disturbances are observed in some patients.
Sleep Promoting Improvement of Declarative Memory
Published in Bahman Zohuri, Patrick J. McDaniel, Electrical Brain Stimulation for the Treatment of Neurological Disorders, 2019
Bahman Zohuri, Patrick J. McDaniel
Another type of explicit memory is semantic memory. It accounts for our “textbook learning” or general knowledge about the world. It’s what enables us to say, without knowing exactly when and where we learned, that a zebra is a striped animal, or that Paris is the major city in France. Scientists aren’t sure where semantic memory happens in the brain; some say in the hippocampus and related areas, while others think it’s widely spread throughout the brain. As with episodic memory, semantic memory ranges from strong (recall) to weak (familiarity). Unlike episodic memory, semantic memory is better sustained over time. We are often able to retain a highly functioning semantic memory into our 60’s, after which it undergoes a slow decline.
Effects of Musical Mnemonics on Working Memory Performance in Cognitively Unimpaired Young and Older Adults
Published in Experimental Aging Research, 2023
Marije W. Derks-Dijkman, Rebecca S. Schaefer, Maartje L. Stegeman, Ilse D. A. van Tilborg, Roy P. C. Kessels
Cognitive aging refers to cognitive change due to nonpathological aging, which does not affect every cognitive domain to the same extent. For instance, semantic memory (for example measured using vocabulary) is relatively resilient to brain aging, whereas for example conceptual reasoning and processing speed show a gradual decline over time (see for an overview Eikelboom, Bertens, & Kessels, 2020). Furthermore, there is considerable heterogeneity among older adults in the rate of decline (Harada, Natelson Love, & Triebel, 2013). Overall, aging-related decline in memory function is consistently reported (Nyberg, Lövden, Riklund, Lindenberger, & Bäckman, 2012). Notably, the ability to maintain and manipulate information for a brief period of time (i.e., working memory [WM] capacity) declines with age (Nyberg et al., 2012) as does everyday memory function (episodic memory [EM]; Nyberg et al., 2012; Rönnlund, Nyberg, Bäckman, & Nilsson, 2005).
Personality and Authenticity in Light of the Memory-Modifying Potential of Optogenetics
Published in AJOB Neuroscience, 2021
Przemysław Zawadzki, Agnieszka K. Adamczyk
Tulving (1972, 1985) famously proposed to distinguish declarative memory into two systems: semantic and episodic memories. Semantic and episodic memories are believed to be functionally independent7 (see e.g., Klein 2013d; Klein, Chan, and Loftus 1999; Klein and Gangi 2010; Klein and Nichols 2012). The semantic memory system contains relatively general and context-free information: it usually “lacks memory” about the source of its disposition, that is, it is experienced as knowledge without reference to the circumstances of where and when it was acquired; furthermore, it is not usually self-referential, although it can include information about the self (see Klein, Gabriel, et al. 2008; Klein and Gangi 2010; Klein and Lax 2010; Klein and Nichols 2012; Renoult et al. 2012). The authors which hold this last view claim that semantic memory stores factual self-knowledge and also contains a special subsystem that stores knowledge about the personality in the form of generalizations.
Is cortical automatic threshold estimation a feasible alternative for hearing threshold estimation with adults with dementia living in aged care?
Published in International Journal of Audiology, 2020
Anthea Bott, Louise Hickson, Carly Meyer, Fabrice Bardy, Bram Van Dun, Nancy A. Pachana
Over 90% of adults living with dementia in an aged care home (ACH) will have a mild or worse hearing impairment (Hopper et al. 2016; Jupiter 2012), meaning they have a dual sensory-cognitive communication disability. Dementia, an umbrella term for a group of neurodegenerative diseases, typically disrupts semantic memory and language function (Verma and Howard 2012), and impairs conversations as individuals progressively lose the ability to recall words and events (Bayles, Tomoeda, and Trosset 1992; Caramelli, Mansur, and Nitrini 1998). Age-related hearing impairment is caused principally by damage to the sensory structure of the cochlea, which results in difficulty understanding speech particularly in the presence of noise (Tun, McCoy, and Wingfield 2009; Wingfield, Tun, and McCoy 2005). When the two conditions of dementia and hearing impairment co-occur, communication difficulties become exacerbated and the individual experiences a more severe communication disability, compared to that of an individual with dementia or hearing impairment in isolation (Guthrie et al. 2018; Slaughter and Bankes 2007). Thus, hearing interventions have been proposed as being important for adults with dementia and hearing impairment (Hopper and Hinton 2012; Pichora-Fuller et al. 2013). However, to access appropriate hearing interventions; individuals living with dementia must first have their hearing evaluated.