The Snellgrove Maze Task (SMT)™

Screening for the likely on-road competence of older drivers with mild cognitive impairment (MCI), stroke, or early dementia
001
RESEARCH

The purpose of cognitive screening tests such as the SMT is to estimate the likelihood of genuine cognitive impairment, inferred from the relationship between patients’ scores to reference norms.

002
BUILD

The digital SMT represents the only known digital screener of the likely driving competence of older people with MCI or early dementia. It is administered on various tablet devices using a handheld stylus pen. The digital SMT replicates the original exactly in terms of size and task requirements

003
OPTIMIZE

The results will be available through a user account. This will include a pictorial representation of the patients performance, providing both qualitative and quantitative information.

The Snellgrove Maze Task (SMT) : Version 1 (Pencil & Paper) versus Version 2 (Digital)

The pencil and paper version of the SMT is out of license, and has been replaced by the digital format. The Digital SMT (Version 2) provides more standardised administration, automated scoring, and richer data performance than the paper version.

Feature SMT Version 1
(Pencil + Paper)
SMT Digital Version 2
(Tablet + Stylus)
Standard Snellgrove Maze Administration
Established Clinical Familiarity
Client Acceptability
Completion Time Measurement ✓ Manual timing ✓ Automatic timing
Error Recording ✓ Manual observation ✓ Automatic capture
Scoring ✓ Manual ✓ Automatic
Report Generation ✓ Instant
Data Storage Paper files Secure digital records
Progress Monitoring Over Time Difficult ✓ Automatic comparison
Longitudinal Tracking Limited ✓ Built-in
Research Data Collection Manual entry required ✓ Automatic export
Standardised Administration Variable ✓ Consistent
Clinician Administrative Burden Higher Lower
Movement Analysis Not possible ✓ Available
Pause/Hesitation Analysis Difficult ✓ Captured automatically
Audit Trail Limited ✓ Complete digital record
Multi-site Data Collection Difficult ✓ Easy
Telehealth Potential No Possible future capability
Environmental Sustainability Paper dependent Reduced paper usage

The point at which cognitive decline in older people renders driving unsafe has proven not easy to determine, and the development of a screening instrument has been widely advocated.

To overcome the practical and conceptual limitations of previous attempts to develop an appropriate instrument, the pencil and paper version of the Snellgrove Maze Task (SMT) was developed in 2006.

Description

In its original format, the SMT was a timed pencil and paper screening test of the cognitive domains of attention, visuoconstructional skills, and the executive functions of planning and foresight, all of which are required for safe driving.

A study has examined the performance characteristics of the SMT, and estimated its criterion-referenced validity, using a group of 115 older drivers with MCI or early dementia recruited from an Outpatient Memory Clinic in South Australia (SA). The gold standard used for driving competence was a standardised on-road driving assessment administered by authorised and accredited driving instructors employed by Transport SA. They were unaware of the cognitive status of participants. The SMT was able to be standardized, and found to be simple, brief to administer and score, and safe and acceptable to the target group. Scores (time for completion in seconds, and number of errors) were not influenced by age, gender, educational attainment, or country of birth. The SMT only measured those skills required for safe driving; speed for attention (SMT time), and visuoconstructional skills, and the executive functions of planning and foresight (SMT errors). In this sample the SMT time and error scores predicted on-road driving competence with high sensitivity, specificity, and overall accuracy (Snellgrove, 2005, 2006).

Subsequent independent studies have supported the criterion-referenced validity, sensitivity, specificity, and overall accuracy of the pencil and paper version of the SMT (Carr et al., 2011; Barco et al., 2014; Ott et al., 2013,). The SMT has been recommended for the screening of likely on-road competence of older drivers with early cognitive impairment, and has been well accepted among researchers, clinicians and patients for its ease of use and short administration time (American Geriatrics Society, 2016; Antimisiaria & Morton, 2017; ANZSGM Position Statement, 2009; Bolz & Galvin, 2015; Canadian Stroke Best Practice Recommendations, 2019; Chun, 2020; Cochrane Database Systematic Reviews, 2013; Ham’s Primary Care Geriatrics, 2021; Mwarni et al., 2013; Platz, 2021; RACP & AFRM Position Statement, 2014).

Some pencil and paper cognitive assessment techniques can suffer from human error and bias, despite standardised administration. Computer based technologies are increasingly common in neuropsychology with benefits of standardisation of administration, immediate scoring, accurate recording, and secure data storage (Bracken et al., 2018). For example, and specific to older adults with MCI or early dementia, the Digital Clock Drawing Test (Muller et al., 2017), and Digital Trail Making Test (Dahmen et al., 2017) have been shown to measure the same aspects of cognition as their original pencil and paper versions.

The digital SMT represents the only known digital screener of the likely driving competence of older people with MCI or early dementia. It is administered on various tablet devices using a handheld stylus pen. The digital SMT replicates the original exactly in terms of size (11 cm2, 14 cm2 for the SMT), and task requirements. The results will be available through a user account and users will also receive an email with a link to results. This will include a pictorial representation of the patients performance, providing both qualitative and quantitative information.

References

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