Virtual Reality Technology in Cognitive Rehabilitation Application: Bibliometric Analysis


IntroductionBackground

Cognition refers to the mental processes associated with acquiring knowledge and converting it into mental activities []. Cognitive function is composed of multiple cognitive domains such as memory, language comprehension ability, spatial orientation, executive ability, and computing power []. Cognitive dysfunction refers to a decline in one or more domains of cognition caused by various factors. The main symptoms include poor responsiveness, apathy, reduced proactive behavior, and short-term memory impairment, which in turn affects the individual’s activities of daily living [].

Cognitive impairment increases stroke risk in older adults []. In the presence of a stroke, dementia onset might occur 10 years earlier, with up to one-third of persons who have experienced a stroke being diagnosed with dementia [,]. Therefore, it is crucial to explore treatments that could prevent or delay cognitive impairment. Owing to the limited effectiveness of pharmacological treatments, nonpharmacological interventions to treat cognitive deficits have been widely studied in recent years []. Several advantages of computer-assisted cognitive rehabilitation have been demonstrated, such as individualized, flexible, and economical programs that provide immediate feedback []. In this type of treatment, technologies such as robots, noninvasive brain stimulation, wearable systems, and neuroprosthetics were used. Among these, virtual reality (VR) shows great potential for neurorehabilitation [].

A VR system can be defined as a highly interactive 3D digital media environment. Users can receive multisensory feedback, such as auditory, tactile, and visual feedback, in the simulated environment []. Developed in the 1990s and used as a tool to assess and treat diseases [], VR has the advantage of providing an environment that simulates the sensation of the real world, combined with the situations and physical needs in daily lives []. Several studies have confirmed the effectiveness of VR in treating diseases such as anxiety, cognitive decline in older adults, and bulimia nervosa []. Jang et al [] found that sensory feedback during VR training affected neuroplasticity and promoted brain reorganization. Optale et al [] conducted a randomized controlled trial to examine the effectiveness of a VR intervention in older adults with memory deficits. The control group was treated with music therapy and the treatment group underwent 3 months of VR memory intervention. After completing the training series, the VR group showed significant improvements in memory tests, especially in long-term recall, with an effect size of 0.7 []. The study by Burdea et al [] showed that individuals with chronic poststroke symptoms in the VR group achieved significant improvements in depression (effect size=0.75) and cognition (effect size=0.46; P<.05). These examples suggest that VR can be used to improve impaired cognitive functions.

Research Problem and Aim

Bibliometrics is the cross-disciplinary science of quantitative analysis of all knowledge carriers using mathematical and statistical methods. It is a commonly used method to identify the development of a certain field []. The advantage of bibliometrics is that it can help scholars quickly grasp the research hot spots and development trends of a specific research area by analyzing citations, cocitations, distribution of countries or regions, authors, and journals in the research field []. The study by Keshner et al [] applied topic modeling methods to 3141 publications included in the Web of Science (WoS), highlighting the research emphasis on VR in rehabilitation. Studies on VR-based cognitive rehabilitation have been published worldwide. However, there is little research that analyzes the scientific output in this field from a bibliometric and visualization perspective. Understanding the research status and hot spots in this field is of great significance for promoting the rehabilitation of disorders related to cognitive impairment. Therefore, based on the WoS Core Collection, this study comprehensively analyzed the research field to provide a reference for future research.


MethodsData Sources and Search Strategy

In this study, only articles and reviews published in English between 2001 and 2021 were included. The data used in this study were downloaded from the WoS Core Collection. The search strategy was as follows: (1) topic (“reality” OR “VR”) AND (“cognition” OR “cognitive function” OR “cognitive impairment” OR “cognitive dysfunction” OR “cognitive rehabilitation”); (2) the document type was selected as “Article” OR “Review”; (3) the language was selected as “English”; (4) the dates of the search were from January 1, 2001, to December 20, 2021. In total, 1286 documents met the selection criteria.

Screening Strategy

The structured approach by Kable et al [] to searching and critiquing the research literature was used to guide and support this review. In this study, 2 reviewers (DH and YC) screened the search results independently, and the results were then cross-checked. Upon encountering any disagreements, a third researcher (SC) was consulted. All the researchers received training in document retrieval and screening by studying the textbook Medical Literature Information Retrieval [].

WoS generates and provides keywords plus for research publications. Keywords plus are words and phrases that are generated using algorithms based on the titles referenced or cited in the documents. WoS-assigned keywords plus express the knowledge structure of the discipline and interconnectedness of different research areas []. During the literature selection process, the titles, abstracts, keywords, and keywords plus of the articles were used to accept or remove published material. Articles that did not contain content related to cognition and VR in these parts were considered to be irrelevant to the topic. The author, title, publication year, and journal were used to identify duplicate records. In total, 20 duplicate records and 7 irrelevant papers were identified and removed. A total of 1259 articles were exported in the form of a full record and cited references, saved as plain text files, and stored in download_txt format ().

Figure 1. Flowchart of literature selection. View this figureData Analysis

In this study, CiteSpace (version 5.8.R2; Drexel University), Scimago Graphica (version 1.0.16; Scimago lab), and gCLUTO (version 1.0; Kerapis lab) software were used to perform the bibliometric visual analysis. CiteSpace was used to analyze the distribution of countries or regions, authors, journals, and cocited references. Scimago Graphica was used to generate geographic visualization maps of the countries or regions. gCLUTO was used for the keyword clustering analysis. Repeated bisection was chosen as the clustering method. The similarity was calculated by choosing the cosine function. The clustering criterion function was set to I2. The clustering results with a high ISim and low ESim were selected [], and the number of clusters was adjusted.

Ethical Considerations

No application for an ethical permit was submitted for this paper. According to the Chinese Hospital Association, an ethics review was not required for this secondary analysis of published data.


ResultsThe Annual Trends of Publications

The number of documents published in each period reflects the development trend of research in the field. plots the distribution of annual research publications on the application of VR in cognitive rehabilitation in the past 20 years.

Microsoft Excel 2019 was used to conduct linear regressions using the Trendline function and polynomials. The dotted lines in are polynomial fitting created by the application, which predict future publication trends in this field. The trendline equation is y = 1.22x2 – 10.17x + 25.54. In this equation, y represents the number of publications, and x represents the ID of publication years in temporal order. Model fitting curve revealed a positive trend in annual publication numbers over the past 20 years (R2=0.977; the closer R2 is to 1, the better the fit of the trendline). The trend line shows that the number of publications will continue to increase in the future.

According to the number of publications, the publication year can be divided into 3 periods: from 2004 to 2011, from 2012 to 2016, and from 2017 to 2021. As shown in , no relevant papers were published before 2004. From 2004 to 2016, the number of articles in this field increased annually; however, the growth rate was relatively slow. The number of publications in 2017 reached 101, surpassing 100 for the first time. From 2017 to 2021, the number of published articles increased significantly, indicating that an increasing number of scholars have begun to focus on the potential of VR in the field of cognitive rehabilitation.

Figure 2. Annual publication outputs and the model fitting curve of time trend of virtual reality in cognitive rehabilitation. View this figurePopular Research Themes

Each publication indexed in the WoS is associated with one or more subject categories (SCs). We identified the top 10 SCs (). The most popular research areas were neurosciences and neurology (n=392), followed by psychology (n=314), computer science (n=131), and rehabilitation (n=125). SC “computer science” accounted for only 5.2% (7/134) of publications during period 1 but increased to 10.3% (93/907) during period 3. SC “health care sciences and services” accounted for 0.8% (1/134) of publications during period 1 and then increased to about 4.9% (44/907) during period 3.

The 10 most frequently studied diseases are listed in . Aging is listed in the table because human aging is usually accompanied by typical structural and neurophysiological changes in the brain and varying degrees of cognitive decline []. Reviews that aimed to investigate the status of VR aid treatment for neurological or psychiatric disorders were not included in the statistics because they did not investigate a specific disease. Stroke, dementia, and mild cognitive impairment (MCI) were the 3 major research areas of the publications.

Table 1. The number of publications in the top 10 Web of Science (WoS) subject categories for the total study period and for each period.WoS subject categoriesTotal (N=1416), n (%)Period 1 (n=134), n (%)Period 2 (n=375), n (%)Period 3 (n=907), n (%)Neurosciences and neurology392 (27.7)35 (26.1)109 (29.1)248 (27.3)Psychology314 (22.2)32 (23.9)84 (22.4)198 (21.8)Computer science131 (9.2)7 (5.2)31 (8.3)93 (10.3)Rehabilitation125 (8.9)16 (11.9)36 (9.6)73 (8.1)Psychiatry124 (8.8)17 (12.7)34 (9.1)73 (8.1)Engineering110 (7.8)7 (5.2)24 (6.4)79 (8.7)Geriatrics and gerontology71 (5.0)6 (4.5)21 (5.6)44 (4.9)Health care sciences and services54 (3.9)1 (0.8)9 (2.4)44 (4.9)Education and educational research48 (3.4)7 (5.3)11 (2.9)30 (3.3)Behavioral science47 (3.4)6 (4.5)16 (4.2)25 (2.8)Table 2. Top 10 most frequently studied diseases in virtual reality–based cognitive rehabilitation (N=1259).RankingDiseasePublication, n (%)1Stroke104 (8.26)2Dementia91 (7.23)3Mild cognitive impairment83 (6.59)4Aging75 (5.96)5Brain injury64 (5.08)6Schizophrenia spectrum and other psychotic disorders60 (4.77)7Parkinson disease45 (3.57)8Multiple sclerosis22 (1.75)9Autism spectrum disorder20 (1.59)10Posttraumatic stress disorder11 (0.87)Distribution of Countries or Regions

The data were imported into CiteSpace, “Country” was selected as a node, the number of objects in each time slice was set to 50, and the minimum spanning tree algorithm was used to draw the countries or regions cooperation network map (). A total of 1259 articles were published in 62 countries or regions. The size of the node label represents the number of papers published in the country or region. The larger the node font, the higher the number of papers published. The purple outer circle of the node indicates that the node has a high centrality. The centrality of a node is a graph-theoretical property that measures the importance of the node’s position in a network. A commonly used centrality metric is betweenness centrality. CiteSpace helped identify pivotal points by measuring the betweenness centrality of a node. It quantifies the probability that the node is on an arbitrary shortest path in the graph. Nodes with high betweenness centrality tend to be found in paths connecting different specialties or tipping points in a network []. The betweenness centrality of a node v is defined as follows as g(v):

g(v) =∑s≠v≠t σst(v) / σst(1)

where σst is the total number of shortest paths from node s to node t and σst(v) is the number of shortest paths from s to t going through v [].

Figure 3. Distribution of publications from different countries. View this figure

As shown in , in the field of VR on cognitive rehabilitation, the most significant number of publications came from the United States (328/1259, 26.05%), followed by Italy (140/1259, 11.12%), the United Kingdom (130/1259, 10.33%), China (115/1259, 9.13%), and Germany (101/1259, 8.02%). These 5 countries published 64.65% (814/1259) of the total number of articles. Among the top 10 countries, the United States, the United Kingdom, Australia, Spain, France, Germany, and Canada showed a high degree of centrality.

Scimago Graphica software was used to analyze the countries with more than 5 publications to generate a geographic visualization map (). The lines in the figure represent cooperation between countries, and the edge width of the lines represents the intensity of cooperation. It can be seen that the United States, the United Kingdom, Australia, China, and other countries have actively cooperated with other countries. Moreover, many European scholars have shown interest in the application of VR in cognitive rehabilitation and have conducted international cooperation to a certain extent.

Table 3. Countries with the top 10 publications on virtual reality in cognitive rehabilitation (N=1259).RankingCountryPublication, n (%)Centrality1United States328 (26.05)0.362Italy140 (11.12)0.063United Kingdom130 (10.33)0.354China115 (9.13)0.095Germany101 (8.02)0.16Australia90 (7.15)0.27Spain81 (6.43)0.188Canada81 (6.43)0.19France80 (6.35)0.1510The Netherlands75 (5.96)0.05Figure 4. Geographic locations of countries with more than 5 publications. View this figureAuthors and Cooperative Relationships

A total of 537 authors have published articles on the application of VR in cognitive rehabilitation (). Giuseppe Riva was the most prolific author, with 2.3 (29/1259) of articles, followed by Rocco Salvatore Calabro with 1.91 (24/1259) of articles. Rocco Salvatore Calabro (24/1259, 1.91%), Rosaria De Luca (20/1259, 1.59%), Maria Grazia Maggio (14/1259, 1.11%), and Antonino Naro (14/1259, 1.11%) conducted active cooperation and communication, forming the largest author collaboration network. It is worth noting that the centrality of the top 10 authors was 0 (), suggesting that the influence of the authors on the of VR in cognitive rehabilitation needs to be improved.

Figure 5. Visualization map of authors involved in the application of virtual reality in cognitive rehabilitation. View this figureTable 4. Top 10 productive authors on the application of virtual reality in cognitive rehabilitation (N=1259).RankingAuthorPublication, n (%)Centrality1Giuseppe Riva [,,,]29 (2.3)02Rocco Salvatore Calabro24 (1.91)03Rosaria De Luca20 (1.59)04Maria Grazia Maggio []14 (1.11)05Antonino Naro []14 (1.11)06Silvia Serino [,]13 (1.03)07Placido Bramanti12 (0.95)08Anat Mirelman9 (0.71)09Alfredo Manuli []8 (0.64)010Pietro Cipresso8 (0.64)0Cocited Academic Journals

The journal cocitation analysis revealed the overall structure of the subject and the characteristics of a journal. As shown in , the most cited journal is Plos One (466/28,765, 1.62%). Among the top 10 academic journals, the highest impact factor is neurology (impact factor 9.910). Furthermore, it can be seen that half of the journals in the table belong to quartile ranking position 1. The dual-map overlay of journals represents the topic distribution of the academic journals. In the dual map, the map of the citing journals is on the left, the map of the cited journals is on the right, and the colored paths between them suggest the cited relationships. There are 5 main citation paths, with 2 blue paths, 2 pink paths, and 1 orange path (), representing that the documents published in psychology, education, or social journals are often cited by psychology, education, health, neurology, sports, ophthalmology, molecular biology, or immunology journals, and the documents published in molecular biology or genetics journals are often cited by psychology, education, health, neurology, sports, or ophthalmology journals.

Table 5. Top 10 cocited journals that published articles on the application of virtual reality in cognitive rehabilitation (N=28,765).RankingCocited journalCitation, n (%)Impact factor based on Clarivate Analytics Journal Citation Report (2020)JCRa1Plos One466 (1.62)3.240Qb22Neuropsychologia377 (1.31)3.139Q13Frontiers in Human Neuroscience353 (1.23)3.169Q34Cyberpsychology Behavior and Social Networking349 (1.21)4.157Q15Frontiers in Psychology319 (1.11)2.988Q26Neurology318 (1.11)9.910Q17Archives of Physical Medicine and Rehabilitation305 (1.06)3.966Q18Neuroscience295 (1.03)3.590Q29Neuroimage268 (0.93)6.556Q110Presence: Teleoperators and Virtual Environments265 (0.92)0.597Q4

aJCR: Clarivate Analytics Journal Citation Report.

bQ: quartile ranking position.

Figure 6. The dual-map overlay of journals on the application of virtual reality in cognitive rehabilitation. View this figureCocited References

As a statistical approach to detecting research trends, cocitation refers to the phenomenon in which 2 or more articles are cited by other articles at the same time. When a group of authors cite a common set of documents, these cocitations indicate documents that may contain concept symbols []. Cited articles are the foundations upon which current research is being conducted; they represent the intellectual base [,]. These publications may contain foundational theories, groundbreaking early works, and methodological principles in the field []. Among the 821 cocited references retrieved, shows the 10 most frequently cited references, of which “Using Virtual Reality to Characterize Episodic Memory Profiles in Amnestic Mild Cognitive Impairment and Alzheimer’s Disease: Influence of Active and Passive Encoding” is the most frequently cited (n=26).

Table 6. Top 10 cocited references on the application of virtual reality in cognitive rehabilitation.RankingReferenceNumber of citationCentrality1Using Virtual Reality to Characterize Episodic Memory Profiles in Amnestic Mild Cognitive Impairment and Alzheimer’s Disease: Influence of Active and Passive Encoding2602Cognitive Training on SStroke Patients via Virtual Reality-Based Serious Games250.023A Feasibility Study With Image-Based Rendered Virtual Reality in Patients With Mild Cognitive Impairment and Dementia230.044Computerized and Virtual Reality Cognitive Training for Individuals at High Risk of Cognitive Decline: Systematic Review of the Literature230.065The Effectiveness of Virtual Reality for People With Mild Cognitive Impairment or Dementia: a Meta-analysis220.016Benefits of Virtual Reality-Based Cognitive Rehabilitation Through Simulated Activities of Daily Living: a Randomized Controlled Trial With Stroke Patients220.077A Succinct Overview of Virtual Reality Technology Use in Alzheimer’s Disease220.148Effects of Virtual Reality-Based Physical and Cognitive Training on Executive Function and Dual-Task Gait Performance in Older Adults With Mild Cognitive Impairment: a Randomized Control Trial2109Effects of Virtual Reality-Based Training With BTs-Nirvana on Functional Recovery in Stroke Patients: Preliminary Considerations200.0110Virtual Reality in the Assessment, Understanding, and Treatment of Mental Health Disorders200.03Distribution of Keywords

By analyzing the keywords, we can summarize the study topics in a specific field and explore hot spots. Data cleaning was performed to remove coding errors, because different articles may use different keywords to refer to the same concept. For example, “older people,” “elderly,” and “old adult” represent the same concept, they were recorded as “old adult,” and “cognitive impairment” and “cognitive dysfunction” were combined into the keyword “cognitive impairment.” In all 1259 publications, we obtained 544 keywords. The keyword “virtual reality” has the highest frequency of 851. Other keywords with high frequency include “cognition” (n=236), “rehabilitation” (n=193), “performance” (n=164), “older adult” (n=151), “memory” (n=143), “dementia” (n=143), “Alzheimer’s disease” (n=141), “mild cognitive impairment” (n=125), and “environment” (n=123; ).

CiteSpace burst-detection algorithms were adapted for detecting sharp increases in interest in a specialty []. According to keyword burst detection, lists the top 20 keywords with the strongest citation bursts. The red line represents the duration of the burstness. Among these words, “social cognition” (6.22) was the strongest burst keyword during the period between 2004 and 2021, followed by “environment” (6.00), “brain injury” (5.86), “spatial memory” (5.55), and “episode memory” (5.51).

Table 7. Top 10 keywords related to the application of virtual reality in cognitive rehabilitation.RankingKeywordFrequencyCentrality1Virtual reality8510.062Cognition2360.13Rehabilitation1930.044Performance1640.175Older adult1510.056Memory1430.077Dementia1430.048Alzheimer’s disease1410.069Mild cognitive impairment1250.0410Environment1230.09Table 8. Top 20 keywords with the strongest citation burst related to the application of virtual reality in cognitive rehabilitation.RankingKeywordsStrengthStart yearEnd year2004-20211Brain injury5.86200620132Environment6.00200620093fMRIa4.14200720154Strategy3.45200720155Performance3.41200720126Spatial memory5.55200820147Skill3.45200920148Cognitive function4.78200920139Hippocampus5.352010201710Ecological validity3.522013201711Neuropsychological assessment3.882013201612Human3.852013201513Spectrum disorder3.652013201414Social cognition6.222014201715Prefrontal cortex3.992014201716Episodic memory5.512015201717Serious game3.592017201818Randomized controlled trial3.402018201919Telerehabilitation3.362019202120Recognition3.3420192021

afMRI: functional magnetic resonance imaging.

Different clusters can be formed based on the keywords with different degrees of closeness. Identifying these clusters can provide an intuitive understanding of various hot subfields of research in a particular field. The keyword co-occurrence matrix was imported into gCLUTO for clustering analysis. A keyword clustering hill plot was generated (). Each hill represents a cluster, and there are 7 clusters. The shape of the hill is a Gaussian curve. The height of the hill is proportional to the similarity of the documents within the cluster, while the volume of the hill is proportional to the number of documents contained within the cluster. Only the color of the top of the hill is meaningful, with a red bias representing a low intraclass SD and a blue bias representing a high intraclass SD []. The dendrogram from clustering shows that the hot spots of research on the application of VR in cognitive rehabilitation are focused on MCI in older adults, Alzheimer disease (AD), stroke, and traumatic brain injury (). Cluster 6 was the largest cluster and contained 11 keywords. The high-frequency keywords were “neuropsychological assessment,” “presence,” “embodiment,” and “virtual reality.”

A time-zone view can help show changes in the research trends in a field over time. From the time-zone view, nodes in the same period can be gathered in the same time zone. The year represents the time when the keyword first appears. The link between keywords means that they appear in the same document. It can be seen from that there is no relevant document was published before 2004. Keywords appeared more intensively from 2006 to 2016, but most were related to diseases, such as “brain injury,” “depression,” “Alzheimer’s disease,” and “attention deficit hyperactivity disorder (ADHD).” Keywords related to psychology and psychiatry, such as “anxiety,” “schizophrenia,” and “depression,” appeared in the early stages of VR-based cognitive rehabilitation development. As time goes on, research hot spots such as “telerehabilitation” and “post-traumatic stress disorder” emerged.

Figure 7. Keyword clustering hill plot of publications related to the application of virtual reality (VR) in cognitive rehabilitation. View this figureFigure 8. Clustering dendrogram of keywords of publications related to the application of virtual reality in cognitive rehabilitation. EEG: electroencephalogram. View this figureFigure 9. The keywords time-zone view of publications related to the application of virtual reality in cognitive rehabilitation. View this figureInstitutions

A total of 65.7% (830/1259) of documents on VR-based cognitive rehabilitation were funded. The top 10 funding institutions by the number of publications are listed in . Half of the top 10 funding support institutions are from the United States, indicating that the United States has strong support and substantial funding for research in this field.

presents the research areas funded by these institutions. We noted that they tend to fund multiple disease areas rather than a single disease. The National Institute on Aging (NIA) seems to place greater emphasis on research in neurosciences and neurology and geriatrics and gerontology. Similarly, research in psychiatry is more likely to be funded by National Institute of Mental Health (NIMH).

Table 9. Funding institutions for publications related to the application of virtual reality in cognitive rehabilitation (N=830).RankFundingCountryPublication, n (%)1United States Department of Health Human ServicesUnited States82 (9.9)2National Institutes of Health United StatesUnited States82 (9.9)3European CommissionEuropean Union75 (9)4National Science FoundationUnited States43 (5.2)5National Natural Science Foundation of ChinaChina30 (3.6)6German Research FoundationGerman25 (3)7National Institute of Mental HealthUnited States23 (2.8)8United Kingdom research innovationUnited Kingdom19 (2.3)9Canadian Institutes of Health ResearchCanada19 (2.3)10National Institute on AgingUnited States18 (2.2)Table 10. Top 10 funding institutions and research area on virtual reality in cognitive rehabilitation.
HHSa (n=92), nNIH USAb (n=91), nEuropean Commission (n=94), nNSFc (n=43), nNSFCd (n=29), nDFGe (n=27), nNIMHf (n=27), nUKRIg (n=23), nCIHRh (n=24), nNIAi (n=22), nTotal (n=472), nNeurosciences and neurology3132314958989146Psychology212118133105772107Computer science1171174100032Rehabilitation9106211002435Psychiatry1212100111031151Engineering3011953011033Geriatrics and gerontology442110012419Health care sciences and services440002101113Education and educational research22120011009Behavioral sciences55812

留言 (0)

沒有登入
gif