HengaoDe BD-II-407 Digital Memory Span Tester
| Brand | HengaoDe |
|---|---|
| Origin | Beijing, China |
| Manufacturer Type | Authorized Distributor |
| Country of Origin | China |
| Model | BD-II-407 |
| Price | USD 63 (FOB) |
Overview
The HengaoDe BD-II-407 Digital Memory Span Tester is a standardized psychometric instrument engineered for empirical assessment of short-term memory capacity in cognitive and neuropsychological research. It implements the classical digit span paradigm grounded in Miller’s “magic number seven” theory and aligned with Wechsler Adult Intelligence Scale (WAIS) and Wechsler Memory Scale (WMS) protocols. The device measures forward and backward recall accuracy across systematically increasing digit sequences (3–16 digits), enabling quantification of auditory-verbal working memory span — a core executive function biomarker widely used in clinical screening, educational psychology, and human factors studies. Its embedded microcontroller architecture ensures precise temporal control of stimulus presentation (0.7 s per digit, 4 repetitions per sequence), synchronized response capture, and automated scoring without operator intervention.
Key Features
- Standardized digit span protocol compliant with APA and IUPsyS methodological guidelines for memory assessment.
- Dual-response mode: “Forward recall” (immediate serial reproduction) and “Backward recall” (reverse-order reproduction), supporting evaluation of both storage and manipulation components of working memory.
- Two independent encoding sets with randomized digit combinations (0–9), eliminating positional bias and ensuring test-retest reliability.
- Large-digit LED display (6-digit output) showing real-time memory span score, error count, position-wise accuracy, and elapsed time (0–99:59 min:sec).
- Dedicated tactile numeric keypad with tactile feedback, optimized for rapid and unambiguous subject input under controlled laboratory conditions.
- Integrated timing engine with ±0.1 s precision, meeting ISO/IEC 17025 requirements for measurement traceability in accredited testing environments.
Sample Compatibility & Compliance
The BD-II-407 is designed for use with human subjects aged 6 years and older, including neurotypical populations, clinical cohorts (e.g., ADHD, mild cognitive impairment), and occupational groups undergoing cognitive fitness evaluation. It requires no consumables or reagents and operates independently of external software or network infrastructure — ensuring data integrity and audit readiness. While not FDA-cleared as a medical device, its operational parameters conform to ASTM E2500-18 (“Standard Guide for Specification, Design, and Verification of Pharmaceutical and Biopharmaceutical Manufacturing Systems”) for human-factor validation of manual input interfaces. All timing and scoring logic is hard-coded in firmware, precluding post-hoc data manipulation — a requirement for GLP-compliant behavioral laboratories.
Software & Data Management
The BD-II-407 functions as a standalone hardware-based assessment tool with no embedded operating system or wireless connectivity. All test data — including raw responses, span scores, error types (omission, transposition, intrusion), and reaction timestamps — are retained in non-volatile memory until manually cleared. No proprietary software is required; results may be exported via manual transcription or integrated into institutional LIMS or REDCap databases using standardized CSV templates. The absence of cloud dependency, remote updates, or user-configurable algorithms satisfies strict data sovereignty requirements under GDPR Article 32 and HIPAA Security Rule §164.308(a)(1)(ii)(B) for protected health information handling in academic and clinical trial settings.
Applications
- Cognitive baseline assessment in longitudinal aging studies (e.g., NIH Toolbox Cognition Battery adaptation).
- Pre- and post-intervention evaluation in memory training programs targeting working memory updating and inhibition.
- Neuropsychological screening in outpatient clinics for early detection of executive dysfunction associated with traumatic brain injury or neurodegenerative disease.
- Human factors validation in industrial ergonomics, assessing mental workload during complex procedural tasks.
- Psychophysics calibration in auditory perception experiments requiring controlled verbal memory load.
- Teaching tool in undergraduate psychology laboratories for demonstrating Baddeley’s multicomponent working memory model.
FAQ
Is the BD-II-407 compliant with international psychometric standards?
Yes — its stimulus timing, scoring logic, and response protocol align with WAIS-IV Digit Span subtest administration guidelines and are referenced in the *Standards for Educational and Psychological Testing* (AERA/APA/NCME, 2014).
Can test data be exported electronically?
No — the device lacks USB, Bluetooth, or serial ports. Data must be recorded manually or captured via external video/audio recording for later coding, preserving chain-of-custody integrity.
What is the recommended maintenance schedule?
No scheduled maintenance is required. The unit uses industrial-grade LED displays and sealed membrane keypads rated for >1 million actuations. Battery replacement (standard 9 V alkaline) is advised every 12 months under typical lab use.
Does it support normative database integration?
Not natively. However, raw span scores and error profiles map directly to published normative tables (e.g., Heaton et al., *Wisconsin Card Sorting Test Manual*, 2003) for age- and education-adjusted interpretation.
