Estimated Prevalence of the Target Population for Brain-Computer Interface Neurotechnology in the Netherlands

Abstract

Background: People who suffer from paralysis have difficulties participating in society. Particularly burdensome is the locked-in syndrome (LIS). LIS patients are not able to move and speak but are cognitively healthy. They rely on assistive technology to interact with the world and may benefit from neurotechnological advances. Optimal research and design of such aids requires a well-defined target population. However, the LIS population is poorly characterized and the number of patients in this condition is unknown.

Objective: Here we estimated and described the LIS patient population in the Netherlands to define the target population for assistive (neuro)technology.

Methods: We asked physicians in the Netherlands if they had patients suffering from severe paralysis and communication problems in their files. Physicians responding affirmatively were asked to fill out a questionnaire on the patients' status.

Results: We sent out 9570 letters to general practitioners (GPs), who reported 83 patients. After first screening, the GPs of 46 patients received the questionnaire. Based on the responses, 26 patients were classified as having LIS. Extrapolation of these numbers resulted in a prevalence of 0.73 patients per 100 000 inhabitants. Notable results from the questionnaire were the percentage of patients with neuromuscular disease (>50%) and living at home (>70%).

Conclusions: We revealed an etiologically diverse group of LIS patients. The functioning and needs of these patients were, however, similar and many relied on assistive technology. By characterizing the LIS population, our study may contribute to optimal development of assistive (neuro)technology.

Keywords: assistive technology; brain-computer interface; brain-stem stroke; locked-in-syndrome; neuromuscular disease; prevalence.

Figure 1

Flowchart of patient recruitment and selection. Note that the total number of General Practitioners addressed is a combination of the GPs extracted from the database when the first letter was sent and the new and changed records of the database at the time point the second letter was sent. In the end, in total, only 42 filled-out questionnaires were received, note that 10 GPs did not return the questionnaire (i.e. because of lack of time).

Figure 2

Distribution of the primary method for communication and the remaining motor functions of the LIS-patients of this study. The method for communication and the remaining motor functions are related as shown by Fisher’s exact test (see text). Columns are given as percentages, the numbers in the columns represent the number of patients for that specific sub group. The division of the patients over the categories has been made relatively coarsely and the category mouth/head, for example, includes mouth, face and neck movements. The categories "Other" contain responses that did not fit within one of the larger categories specified (i.e. eyes & leg). The total number of patients was 42.