Development of a new high sensitivity mechanical switch for augmentative and alternative communication access in people with amyotrophic lateral sclerosis

Abstract

BackgroundPeople with Amyotrophic Lateral Sclerosis (PwALS) in the advanced phase are critically affected by an almost total loss of mobility and severe communication problems. Scanning access based on the patient’s interaction with a sensor (or switch) that intercepts even a weak body movement is a valid communication aid. However, its use becomes limited with the progressive decline of residual movements. To overcome this problem, we designed a new sensor, the Lever Magnetic-spring Mechanical Switch (LeMMS), allowing repeated activation/release cycles requiring a very small activation force.MethodsThe LeMMS was applied and validated in a group of 20 PwALS in an advanced stage of disease. All subjects were regular users of communication aids employing other sensors, but which they could no longer operate their sensors (different from LeMMS). Patients were assessed at baseline (t0) and after one (t1), 6 (t2) and 12 (t3) months. Assessment at t0 included administration of standardized clinical scales, the Click-Test-30 counting the maximum number of LeMMS activations in 30 s, and thumb/fingers strength assessment with the Kendall scale. The QUEST 2.0-Dev questionnaire was administered at t1. Some use-related information and the Click-Test-30 were collected at t1, t2 and t3.ResultsAfter one training session, all patients could operate the LeMMS with minimal residual movement of one finger. At t1, they used it on average 5.45 h/day. The mean score of the QUEST 2.0-Dev was 4.63, suggesting strong satisfaction with the LeMMS. Regarding Click-Test-30 scores, no significant difference was found between t0 and t1, but performance at t2 and t3 declined significantly (p < 0.005 vs. t0). At t3, 9/20 patients were still able to use their communication aid.ConclusionsThis new switch sensor can enable PwALS to use their communication aids for a prolonged time even in the advanced phase of disease. It is easy to use, reliable and cheap, thus representing an intermediate alternative to more sophisticated and costly devices.

Writing Blindly in Incomplete Locked-In Syndrome with A Custom-Made Switch-Operated Voice-Scanning Communicator—A Case Report

“…To evaluate Lisa’s effective ability to interact with a switch, a single session of the click-test [ 37 ] was administered by a physiotherapist with experience in the AAC field. The test required to click (activate/deactivate) the control switch as many times as possible in 30 s, and then count the number of activations.…”

“…To allow Lisa to interact with the computer, we opted for a mechanical switch, based on a lever system and previously created for patients with ALS [ 37 ] (see Appendix A ). The switch needed to be both easy to activate voluntarily and at the same time have a certain resistance to unintentional micro-movements that could activate it at the wrong time.…”

Fostering Daily Life Skills in Young and Older Adults With Neurodegenerative Diseases Through Technological Supports

“…For instance, Caligari et al (2019) designed a new sensor (i.e., the Lever Magnetic-spring Mechanical Switch, LeMMS), ensuring repeated activation and/or releasing cycles requiring a verysmallactionforce.Twentyparticipants,meanagedof59yearsanddiagnosedwithadvanced amyotrophic lateral sclerosis (ALS) were enrolled and exposed to the new technology aimed at enhancing their communication skills. All the participants regularly used other sensors but they wereunabletomanagethetechnologyasconsequenceoftheirclinicalconditions,exceptforthe newLeMMS.Observationsoccurredatthebaseline(T0),andafterone(T1),six(T2),andtwelve…”