Correctness and response time distributions in the MemTrax continuous recognition task: Analysis of strategies and a reverse-exponential model

Abstract

A critical issue in addressing medical conditions is measurement. Memory measurement is difficult, especially episodic memory, which is disrupted by many conditions. On-line computer testing can precisely measure and assess several memory functions. This study analyzed memory performances from a large group of anonymous, on-line participants using a continuous recognition task (CRT) implemented at https://memtrax.com. These analyses estimated ranges of acceptable performance and average response time (RT). For 344,165 presumed unique individuals completing the CRT a total of 602,272 times, data were stored on a server, including each correct response (HIT), Correct Rejection, and RT to the thousandth of a second. Responses were analyzed, distributions and relationships of these parameters were ascertained, and mean RTs were determined for each participant across the population. From 322,996 valid first tests, analysis of correctness showed that 63% of these tests achieved at least 45 correct (90%), 92% scored at or above 40 correct (80%), and 3% scored 35 correct (70%) or less. The distribution of RTs was skewed with 1% faster than 0.62 s, a median at 0.890 s, and 1% slower than 1.57 s. The RT distribution was best explained by a novel model, the reverse-exponential (RevEx) function. Increased RT speed was most closely associated with increased HIT accuracy. The MemTrax on-line memory test readily provides valid and reliable metrics for assessing individual episodic memory function that could have practical clinical utility for precise assessment of memory dysfunction in many conditions, including improvement or deterioration over time.

Toward digitally screening and profiling AD: A GAMLSS approach of MemTrax in China

“…In recognition of an imminent greater widespread impact and social/financial burden from AD, numerous computerized cognitive assessment tools continue to be developed. Primarily developed to specifically measure episodic memory, which is associated with early AD, MemTrax has been implemented and utilized online in various countries for the general population 7,15,24,25 . In this study, MemTrax tests were performed on a large annual exam population to generate reference norms in China…”

Episodic memory assessment: effects of sex and age on performance and response time during a continuous recognition task

“…In the next implementation of MemTrax, May 27, 2014 to May 7, 2022), 602,272 individuals took the test, and there were 344,165 first-time users identified. This analysis divided TC into HITs and CRs ( Ashford et al, 2022a ). The number of HITs corresponded significantly with faster RT-HITs, though CRs did not.…”

“…MemTrax provides a method for quickly and precisely measuring EM, the central process affected by AD and several related dementias. This study re-examined behavioral data produced by the online application of the MemTrax CRT ( Ashford et al, 2019 ), using an approach that separates TC into HITs and CRs, and a novel analytic method for response time, reverse exponential (RevEx) ( Ashford et al, 2022a ). These variables were further examined in this study to determine relationships with age and sex.…”

Brain health registry updates: An online longitudinal neuroscience platform

“…The BHR platform currently administers the following online neuropsychological tests: (1) Cogstate Brief Battery 72 ; (2) MemTrax Memory Test 73,74 ; and (3) Cambridge Cognition Paired Associates Learning, 75 which was added in the summer of 2021. The Lumos Labs NeuroCognitive Performance Tests 76 was previously administered on the BHR platform for 5 years from 2014 until 2019.…”