The top 100 cited neurorehabilitation papers

Abstract

BACKGROUND: Neurorehabilitation covers a large range of disorders, assessment approaches and treatment methods. There have been previous citation analyses of rehabilitation and of its subfields. However, there has never been a comprehensive citation analysis in neurorehabilitation.

OBJECTIVE: The present study reports findings from a citation analysis of the top 100 most cited neurorehabilitation papers to describe the research trends in the field.

METHODS: A de-novo keyword search of papers indexed in the Web of Science Core Collection database yielded 52,581 papers. A candidate pool of the 200 most-cited papers published between 2005 and 2016 was reviewed by the clinician authors. The papers in the top 100 deemed to be irrelevant were discarded and replaced by the most highly-cited articles in the second tier deemed to be clinically relevant.

RESULTS: The most frequently cited neurorehablitation papers appeared in Stroke, Movement Disorders, and Neurology. Papers tended to focus on treatments, especially for stroke. Authorship trends suggest that top cited papers result from group endeavors, with 90% of the papers involving a collaboration among 3 or more authors.

CONCLUSION: Treatment studies, often focused on stroke, appear to have the highest impact in the field of neurorehabilitation.

1 Introduction

The number of citations a manuscript receives is often considered a measure of impact and merit. Citation analyses, or the systematic study of patterns in publications, have been used to evaluate scientific activity for many decades (Narin, 1976) and have proliferated in biomedicine in recent years (King, Tam, Fasano, & Lozano, 2016; Sorenson & Weedon, 2011). These analyses are effective for describing the trends in scholarship in a particular area of study.

As a multidisciplinary field, rehabilitation encompasses diverse clinical and research settings. Consequently, results from citation analyses in rehabilitation can be particularly difficult to synthesize, even in the most common areas of practice (Shadgan, Roig, HajGhanbari, & Reid, 2010). Instead, the approach has been to focus on specific subfields in rehabilitation. For instance, the first citation analysis in rehabilitation was an examination of research in physical therapy (Michels, 1982). Subsequent published works have similarly focused on the physical therapy literature (Bohannon & Gibson, 1986; Roberts, 1992; Wakiji, 1997), identifying the core journals in physical therapy (Bohannon & Roberts, 2009), and assessing the relative ranking of a specific rehabilitation journal (Kuhlemeier, 1992).

There has been only one published review of the top cited articles in the broader field of rehabilitation (Shadgan et al., 2010). Findings from this analysis focused on manuscripts published between 1959 and 2002 identified neurorehabilitation as the most common field of study in rehabilitation, accounting for 41% of published papers. There has not, however, been a recent analysis of the growing neurorehabilitation research literature to assess, in a comprehensive manner, the trends in this area. The present manuscript aims to characterize the published literature in neurorehabilitation over the last decade to identify the most frequently cited papers, the journals in which they were published, and the number of authors of these works. This review also provides guidance for future neurorehabilitation research and highlights where there are deficiencies in the current literature.

2 Methods

The data used in the tabulation of each article’s citations originate from the Web of Science Core Collection database, which includes, but is not limited to all papers indexed by the NIH’s MEDLINE® database. To start, a de-novo keyword search strategy was developed and applied (see Appendix A). The search strategy yielded 52,581 published papers in 2,781 journals. Manuscripts in 23 languages other than English were excluded. Next, two selection filters were used to determine which papers would be evaluated in the analysis. The first filter applied was temporal. Only papers published and subsequently indexed in Web of Science Core Collection between January 1, 2005 and April 18, 2016 were considered. As shown in Fig. 1, the authors focused on the past decade, characterized by substantial and increasing productivity.

The second filter applied to the search was relevance to neurorehabilitation. A candidate pool of the top 200 most cited was identified. From the top 100, papers irrelevant to neurorehabilitation were excluded and replaced by the most highly-cited articles in the second tier deemed to be clinically relevant. Relevance to rehabilitation was judged by consensus decisions of the clinician authors NZ, JSK and MO.

After compiling the 100 published papers with the most citations, papers were categorized by content. The type of article (e.g., review or evaluation, treatment study), clinical diagnosis of focus (e.g., Parkinson’s disease, stroke), and symptom type (e.g., aphasia, cognitive impairment) were determined by consensus between the clinician authors. These categories were not mutually exclusive, such that one paper could be classified into more than one category (i.e., review paper and stroke).

3 Results

The top 100 most cited papers are presented in Table 1.

3.1 Journals of top 100 neurorehabilitation papers

To identify journals that were the greatest source of scientific information on neurorehabilitation, a list of the journals in which the most neurorehabilitation articles were published was compiled (see Table 2). With more than one thousand relevant articles published, the journals, Stroke, Movement Disorders, Neurology, Epilepsia, European Journal of Neurology, and International Journal of Stroke were most often a source for neurorehabilitation content.

3.2 Most common focus of neurorehabilitation papers

Among the 100 most cited papers in neurorehabilitation, treatment studies emerged as the most common type of article (38% of the papers). Treatments evaluated in these papers included devices for stroke patients, basic studies using animal models, and surgical interventions for neurological conditions. With the exception of a few papers (4%), all treatment studies cited involved human subjects. There was a significant minority of published papers (9%) testing the efficacy of transcranial magnetic stimulation (TMS) as an intervention for various neurological conditions such as stroke and spinal cord injury.

As would be expected, a number of the most frequently cited papers had to do with approaches to neurorehabilitation. Nine percent of the top 100 papers dealt with advanced treatment guidelines from key governing bodies within the field including the American Heart Association. Another 16% of the papers describe assessment tools for measuring critical outcomes in neurorehabilitation including psychological functioning and cognitive impairment. The relevance of these two outcomes in the literature over the past 10 years is further reflected in the findings that 14% of the top 100 most cited papers focused on psychological symptoms, most frequently depression and anxiety, while another 5% covered cognitive functioning. Another indicator of consensus, review papers, which summarize accumulated evidence on specific areas within neurorehabilitation, also made up 16% of the most frequently cited works.

A look at the most frequently studied disease state among the top 100 cited published papers shed some light on the disease attributes that shape research in this area of the rehabilitation. Stroke was the most commonly studied neurological condition, appearing in 39% of the top 100 cited papers. The high number may speak to the high prevalence of stroke and its widespread global impact. It may also be related to the great potential for rehab gains in cerebrovascular disease. In contrast, Huntington’s disease is a rare and terminal condition, making up only 1% of the top 100 papers. After stroke, the next conditions are considerably less common in the reviewed literature, ranging from 10–12% compared to a 39% for stroke. These conditions included degenerative (Parkinsons’s Disease—11%; Alzheimers/dementia—10%) and other chronic diseases (TBI—11%; epilepsy—12%). Multiple sclerosis, a neurodegenerative disease, accounted for only 4% of the top 100 cited papers. Notably, although spinal cord injury can often co-occur with brain injury, the former appeared in only 6% of the top 100 most cited papers in neurorehabilitation, compared to 11% for TBI.

As with other disorders that compromise functioning, caregivers play a central role in caring for individuals with neurological conditions. This was captured in the 4% of the top 100 papers that focused on caregivers. Most of these papers (75%) focused on the caregivers of individuals with dementia.

3.3 Number of authors of top 100 neurorehabilitation papers

Authorship patterns for each paper were examined. The number of authors ranged from a low of 1 (2%) to a high of 44 (1%). One quarter of the papers (25%) had 4 authors or less. Nearly half (46%) of the papers had between 5 and 10 authors. Nearly one quarter (23%) had between 11 and 20 authors. Six percent had between 21 and 44 authors.

4 Discussion

Neurorehabilitation is the most common field of study in rehabilitation (Shadgan et al., 2010), yet there have been no citation analyses of neurorehabilitation papers to describe the research trends. The most recent comprehensive citation analysis in the broader rehabilitation field was published over five years ago and only included papers through 2002. The present study updates findings from the 2010 publication by focusing on neurorehabilitation papers appearing in print between 2005 and 2015.

First, findings from this citation analysis of the top 100 most cited neurorehabilitation papers show that over the last decade, the field has been dominated by the study of stroke. Shadagan et al. (2010) similarly found from analyzing rehabilitation papers published more than a decade earlier that 41% of neurorehabilitation articles were on stroke and spinal cord rehabilitation. Very likely, substantial resources in neurorehabilitation have been dedicated to the study of stroke because stroke continues to be the leading cause of adult acquired disability in the United States and worldwide (Brenner, Burke, & Skolarus, 2016).

Second, much of the scientific inquiry in neurorehabilitation has been focused on advancing treatments for neurological disorders. Neurorehabilitation in its most fundamental sense is aimed at improving functioning for individuals affected by neurological disorders. For example, this represents a contrast with the related fields of essential tremor and dystonia, where much of the work up till 2015 has been focused on describing the pathophysiology of the conditions (King et al., 2016).

Included among the dozen most often cited journals were Stroke, Movement Disorders, Neurology, Epilepsia, European Journal of Neurology, International Journal of Stroke, Brain Injury, and Journal of Neurotrauma. Seven of the top 30 journals found in the 2010 citation analysis continue to produce frequently cited manuscripts according to these more recent results.

Lastly, as in all of biomedical literature, the authorship trends show that collaboration continues to be common in top cited manuscripts in neurorehabilitation. Shadagan and colleagues (2010) found that only 7% of the most cited papers were written by a single author, the current findings show an even smaller proportion—2%.

Given the high incidence of neurotrauma and neurological disorders, the field of neurorehabilitation remains an important research area. Increased research productivity is clearly indicated on numerous fronts given the often complex, and long-term needs of this patient population and the dearth of adequate literature in many areas of this subspecialty area of rehabilitation.

Conflict of interest

None.