According to a survey by the World Health Organization in 2021, more than 55 million people worldwide suffer from dementia, a number which is rising at a rate of 10 million new cases per year (1). The number of dementia patients worldwide is expected to exceed 150 million by 2050, and the cost of treatment is expected to double by 2030 (2). As the country with the largest number of dementia patients, China accounts for approximately one quarter of global prevalence of dementia (3). Clearly, dementia has become a serious public health problem, placing a heavy burden on society and families. Alzheimer's disease (AD), as the main type of dementia, leads to a loss of function and cognitive and behavioral issues in patients (4), and 90% of dementia patients exhibit behavioral and psychological symptoms of dementia (BPSD), which become manifest as excitement, sleep disorder, anxiety and aggressive behavior (5). These symptoms reduce the quality of life of patients and caregivers (6), increase the cost of care, and entail severe challenges for family caregivers (7), even leading to a deterioration of the relationship between family members (8).

Management of BPSD, cognition and mental status in dementia patients is mainly divided into drug intervention and non-pharmacological intervention categories (9). However, drug interventions are often accompanied by adverse reactions, increasing the risk of death among patients (10), and may lead to cognitive decline and an increase in the number of falls among patients (11). The safety and effectiveness of drug interventions remain controversial (12). Compared with drug interventions, non-pharmacological interventions are more effective in improving cognition and reducing BPSD in dementia patients (13, 14). A number of studies have shown that non-pharmacological intervention has a low level of risk, can effectively manage BPSD symptoms in dementia patients (15), and can accomplish personalized nursing interventions according to the situation of patients and their families (16), which can improve patient quality of life and enhance caregiver satisfaction (17), so this approach is a scientific and effective nursing intervention.

As an important intervention in the non-pharmacological treatment of dementia, music therapy is mainly divided into the categories of active music therapy and passive music therapy (18), that is, active participation in singing, instrument playing and music creation, and passive listening to music. As a nonverbal therapy (19), music therapy is not affected by the course of the disease and can be used at all stages of dementia (20). Participating in singing activities can effectively reduce patients' excited-aggressive moods (21), improve their quality of life, reduce pressure on caregivers, and promote the happiness of family members (22). Personalized music therapy based on patients' musical memory can reduce BPSD (23, 24). A study of 60 patients with moderate to severe dementia who received music therapy intervention reported improvement in psychiatric symptoms and reduced frequency and severity of BPSD (25). Evidence shows that music therapy seems to be effective, but there is no systematic and comprehensive report concerning visual analysis of research hotspots and development trends in music therapy regarding the non-pharmacological management of dementia.

Publications have shown that music therapy appears to be effective in the intervention of dementia. However, as far as we know, no one has systematically analyzed the subject of this field by means of bibliometric analysis. Therefore, this study aims to research hotspots and trends in music therapy intervention for patients with dementia from 2010 to 2021 through bibliometrics. As an effective statistical method, bibliometrics and visual analysis can not only evaluate the published literature but also predict development trends in this field, thus providing a relevant basis for subsequent studies (26). Therefore, based on the WoSCC database, this study used the CiteSpace and gCLUTO software to examine trends and co-occurrence matrices, aiming to analyze the research status, hotspots and development trends in this field, help relevant researchers strengthen their understanding of this field and promote the benign development of relevant research in this field.

The analysis of annual publications, international cooperation and institutions shows that in this research area, annual publications generally show a slowly increasing trend and that the United States has the most publications and the most frequent cooperation among countries. Most research institutions in this field are universities, among which UCL has the strongest comprehensive influence. Although analysis of China's international cooperation and institutions shows that its number of publications ranks second, the central value of China is low, and the country has a lack of influential research institutions in this field. Combined with high-frequency keywords, keyword emergence and the keyword time zone map, we found that the current hotspot in this field is the psychosocial care of patients with dementia. In the time interval chosen, this research field paid more attention to the management and care of the cognitive behavior and function of patients with dementia in the early stage of the disease and explored the mechanisms potentially underlying this aspect. As time progressed, the literature also began to pay more attention to the mental health of patients. Comprehensive analysis of the six clusters found in the biclustering shows that the research hotspots in this field over the past 11 years have mainly focused on autobiographical memory, cognitive function, mental state and BPSD among dementia patients.

In China, dementia has become the fourth leading cause of death among elderly individuals after cancer, heart disease and cerebrovascular diseases (28), which places great pressure on and causes pain to dementia patients, their families, caregivers, and even society as a whole and seriously affects the quality of life of these individuals. The 2018 Guidelines for the Diagnosis and Treatment of Dementia in China indicate that non-pharmacological treatment should be the first choice for psychiatric and behavioral symptoms of dementia and that personalized treatment should be conducted to achieve the best efficacy (29). However, relevant research concerning non-pharmacological intervention remains incomplete. Some dementia patients and their families have insufficient understanding of the disease, resulting in a low attendance rate, difficult care and many problems (30) as well as a lack of exchange and cooperation with other countries and institutions in this research field in China. Therefore, in order to strengthen diagnosis and nursing and improve the health and nursing systems, China should further strengthen exchanges and cooperation with international institutions to carry out in-depth research concerning music therapy intervention for dementia patients, improve the influence of this aspect of this field, and provide more help to dementia patients.

Behavioral and psychological symptoms are the most common symptoms of dementia, with patients often experiencing anxiety, depression, sleep disturbances, apathy and irritability. The physical and mental health of the sufferer is also impaired by life disorders associated with eating difficulties and a strong sense of loneliness (31). Different types of eating difficulties caused by cognitive impairment have been reported to contribute to malnutrition in dementia patients and to increase their risk of respiratory infections (32). Several studies have shown that a lack of social communication in patients with dementia is associated not only with higher mortality but also with increased BPSD and psychological symptoms such as depression and loneliness (33, 34), among which loneliness and isolation are closely associated with dementia. One study of 12,030 participants showed that loneliness increases the risk of dementia by 40% in older adults (35), and another study of 1,547 dementia patients showed that nearly one-third of patients experience moderate social isolation and loneliness (36). Although the causal relationship between loneliness and dementia has not been clearly established (37), enhanced social communication has shown certain benefits in preventing loneliness and improving of cognitive function in dementia patients (38, 39).

Through a comprehensive analysis of the five clusters in the keywords biclustering, it can be concluded that the research hotspots in this field in the past decade have mainly focused on the autobiographical memory, cognitive function, mental state and BPSD of dementia patients. Research in this field were more focused on Alzheimer's patients, aiming to improve the mental symptoms and cognitive behavior of AD patients through music therapy, thereby improving their quality of life. As a common neurodegenerative disease, AD is the most important type of dementia. Symptoms of AD include progressive memory degeneration, language impairment, depressive symptoms and hallucinations, and the disease is accompanied by pathological changes such as cerebrovascular amyloidosis and inflammation (40). Although genetic factors are considered to be the greatest risk factor for AD, the underlying pathogenesis of AD remains unclear, and there is no effective treatment for AD (41). As a non-pharmacological therapy for the treatment of AD, the potential mechanisms of music therapy mainly include the following aspects: (1) improving patients' cognitive neural efficacy and thus affecting neuroplasticity; (2) promoting the regeneration and repair of neurons; (3) affecting hormone levels to prevent deterioration due to the disease; and (4) enhancing autobiographical memory and reducing mental symptoms (42).

At present, the daily life of dementia patients consists mainly of routine nursing care, and the caregiver plays an important role in the treatment process. Nursing homes have become a choice for many families because of the difficulty of caring for individuals with the disease. However, while this approach does relieve pressure on family members, it also entails psychological problems such as guilt and depression (43, 44). In China, more than 90% of dementia patients are cared for by family caregivers. Due to a lack of corresponding social support, family caregivers face great stress and suffer from mental and physical health problems (45). In a UK study involving 1,283 dementia patients, close to 50% of family caregivers reported feeling lonely, and close to 20% of family caregivers reported experiencing severe loneliness (46). Therefore, the psychological status of patients' family members should also be considered, since doing so can also have a positive effect on the nursing care of dementia patients.

As one of the main forms of music therapy, listening to the individual's favorite music or actively participating in musical instrument playing and singing can arouse patients' positive emotions and strongly stimulate changes in neuroplasticity. This method can play a benign role in the treatment of neurological diseases to varying degrees (47). Targeted memory music recall therapy has produced positive effects in improving the cognitive ability and happiness of elderly people (48). Although the underlying therapeutic mechanism of music therapy is unclear, such therapy has been shown to be effective and cost-effective as a nonpharmacological intervention in the treatment of mild to moderate depression in elderly individuals (49), and studies have shown that music therapy can also relieve anxiety by regulating mood (50). Some dementia patients suffer from depression, anxiety and other symptoms, so the use of music therapy has broad clinical value and can also improve the mental state of caregivers (51). In general, music therapy has certain advantages in the treatment of dementia, but there is a lack of a standardized treatment protocol for music stimulation of dementia patients, resulting in differences in treatment results. Most outcomes related to mood and spirit have been measured by self-assessment questionnaires, which may also affect the reliability of the results (52).

This study conducted a bibliometric and visual analysis of relevant studies concerning music therapy intervention for dementia patients in the WoSCC database, and the results indicated that the United States has the most publications and the most frequent cooperation among countries in this field and that and emerging countries are also gradually increasing. Psychological problems faced by dementia patients and the topics of quality of life, individualized music therapy, the mental state of caregivers and other related topics may be important research directions in the future. Therefore, the question of how to develop standardized research protocols and identify unified efficacy evaluation indicators should be a focus of and difficulty for future research.

The original contributions presented in the study are included in the article/Supplementary Material, further inquiries can be directed to the corresponding author.

SY and FZ: study conception and design. LL and DC: administrative support. ZL, YZ, and LZ: collection and assembly of data. LZ, BL, XW, and ZL: data analysis and interpretation. SY and FZ: manuscript writing. All authors final approval of manuscript and contributed to the article and approved the submitted version.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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