For our study, we ex­am­ined the gait be­hav­iour and brain func­tions of 1500 par­tic­i­pat­ing in­di­vid­u­als who are cur­rent­ly en­rolled in var­i­ous clin­i­cal tri­als. In this way, we analysed for the first time how dif­fer­ent pat­terns of gait in old­er peo­ple can be used to di­ag­nose dif­fer­ent types of de­men­tia more ac­cu­rate­ly and pos­si­bly even de­tect Alzheimer’s dis­ease at an ear­ly stage.

We have long had cues that cog­ni­tive prob­lems such as mem­o­ry im­pair­ment and ex­ec­u­tive dys­func­tion can be pre­cur­sors to de­men­tia. Now we see that mo­tor per­for­mance, es­pe­cial­ly the way peo­ple walk, can help di­ag­nose dif­fer­ent types of neu­rode­gen­er­a­tive dis­eases. We were able to iden­ti­fy four in­de­pen­dent gait pat­terns. These in­clud­ed rhythm, tem­po, vari­abil­i­ty, and pos­tur­al con­trol (abil­i­ty of the hu­man body to main­tain an up­right body po­si­tion un­der the in­flu­ence of grav­i­ty). High gait vari­abil­i­ty was found to be as­so­ci­at­ed with low­er cog­ni­tive per­for­mance, which helped iden­ti­fy Alzheimer’s dis­ease with 70 per­cent ac­cu­ra­cy. So-called gait vari­abil­i­ty in­cludes changes from step-to-step in length or time that oc­cur dur­ing walking.

This is the first strong ev­i­dence that gait vari­abil­i­ty is an im­por­tant mark­er of process­es oc­cur­ring in ar­eas of the brain as­so­ci­at­ed with both cog­ni­tive im­pair­ment and mo­tor con­trol. We have shown that high gait vari­abil­i­ty as a mark­er of cog­ni­tive-cor­ti­cal dys­func­tion can re­li­ably iden­ti­fy Alzheimer’s dis­ease com­pared with oth­er neu­rode­gen­er­a­tive dis­eases. In cog­ni­tive-cor­ti­cal dys­func­tion, the abil­i­ty of in­di­vid­u­als to per­form mul­ti­ple tasks as well is im­paired. This in­cludes, for ex­am­ple, speak­ing while walk­ing or cut­ting veg­eta­bles while talk­ing to family.

Es­tab­lish­ing gait vari­abil­i­ty as a mo­tor mark­er for cog­ni­tive de­cline and dif­fer­ent types of med­ical con­di­tions could make it pos­si­ble to use gait as­sess­ment as a clin­i­cal test, for ex­am­ple, by us­ing wear­able tech­nol­o­gy to cap­ture gait, the re­search team ex­plains. Gait vari­abil­i­ty could then be mea­sured in clin­ics in a sim­i­lar way to car­diac ar­rhyth­mias, for ex­am­ple, and used for med­ical assessment.

CON­CLU­SION

In­creased gait vari­abil­i­ty may re­flect the pro­gres­sion of cog­ni­tive im­pair­ment in neu­rode­gen­er­a­tive dis­eases, and po­ten­tial­ly with speci­fici­ty for Alzheimer’s dis­ease de­men­tia, which is the ar­che­typ­al cor­ti­cal cog­ni­tive dis­or­der. Our study, there­fore, sup­ports the no­tion that, com­pared with oth­er gait pa­ra­me­ters, gait vari­abil­i­ty may be a pu­ta­tive mark­er of cog­ni­tive-cor­ti­cal de­te­ri­o­ra­tion in neu­rode­gen­er­a­tive dis­or­ders. A fu­ture study us­ing a val­i­da­tion co­hort is re­quired to con­firm our findings.