Preliminary Validation of the Bulgarian SCCAN: Initial Reliability, Validity, and Screening Accuracy Across Neurological Populations

Bulgaria is facing a critical gap in standardized assessment tools for cognitive-communicative abilities in adults with neurological disorders. A recent study, published in Frontiers in Psychology, reports promising preliminary validation evidence for the Bulgarian version of the Scales of Cognitive and Communicative Ability for Neurorehabilitation (SCCAN-B), an instrument designed to address this unmet need. The research, conducted at a tertiary university hospital in Plovdiv, involved 89 Bulgarian-speaking adults, including neurotypical controls and individuals diagnosed with mild cognitive impairment (MCI), Alzheimer’s disease (AD) dementia, and ischemic stroke.

The SCCAN-B aims to provide a comprehensive evaluation of cognitive-communication skills, which are frequently impacted by neurological conditions. These deficits can significantly affect an individual’s daily functioning, autonomy, and overall quality of life. Until now, Bulgaria has lacked a standardized tool to meticulously assess these abilities, relying primarily on broader screening instruments like the Bulgarian version of the Mini-Mental State Examination (MMSE-B). The development and validation of the SCCAN-B represent a significant step towards improving diagnostic accuracy and tailoring rehabilitation strategies for Bulgarian patients.

The Need for a Standardized Cognitive-Communicative Assessment in Bulgaria

Cognitive-communicative disorders are a common consequence of neurological conditions such as Alzheimer’s disease, stroke, and mild cognitive impairment. These disorders manifest as deficits in crucial areas including attention, orientation, memory, language expression and comprehension, reading, writing, and problem-solving. The impact of these impairments extends beyond individual function, affecting rehabilitation outcomes, social integration, and overall quality of life. Comprehensive assessment is therefore paramount for accurate differential diagnosis and effective therapy planning.

While international research highlights the importance of psychometrically sound assessment tools, their availability varies significantly across linguistic and cultural contexts. Bulgaria has historically faced limitations in this regard. The MMSE-B, while valuable for general cognitive screening, does not offer the detailed, domain-specific insights required for nuanced cognitive-communication profiling. The SCCAN, originally developed and validated in English, offers a robust solution by assessing a wide range of cognitive-communication abilities. Its adaptation and validation for the Bulgarian population, now reported as the SCCAN-B, fills a crucial void in clinical practice.

Methodology: Rigorous Adaptation and Validation

The study’s methodology involved a systematic process of translation and cultural adaptation of the original SCCAN instrument. This process adhered to international guidelines for cross-cultural test adaptation, ensuring semantic, conceptual, cultural, and functional equivalence. Key steps included:

• Dual Translation: Two independent translators, experienced in medical terminology and speech-language pathology, translated the SCCAN materials from English to Bulgarian.
• Consensus Review: The research team and clinical experts compared the two translations, resolving any discrepancies to produce a unified Bulgarian version.
• Back-Translation: This Bulgarian version was then translated back into English to verify semantic correspondence with the original instrument.
• Pilot Testing: The adapted Bulgarian version underwent pilot testing to assess comprehension, cultural relevance, and practical feasibility among Bulgarian speakers.

Culturally specific adaptations were carefully implemented to maintain functional equivalence. For instance, the phonemic fluency task was adapted to a Bulgarian letter (‘M’), a map of Bulgaria replaced a US map, the emergency number was changed from ‘911’ to the European standard ‘112’, US-specific medication names were replaced with familiar Bulgarian equivalents, and a culturally relevant idiom ("she has golden hands") substituted an English one ("she has a green thumb"). Date and currency formats were also adjusted to Bulgarian conventions. These modifications were designed to enhance cultural accessibility without altering the fundamental cognitive-communicative demands of the tasks.

The study recruited 89 Bulgarian-speaking adults from St. George University Hospital in Plovdiv. Participants were categorized into four main groups: Alzheimer’s disease (n=21), Mild Cognitive Impairment (n=13), acute ischemic stroke (n=24), and healthy neurotypical controls (n=31). A small group of individuals with multiple sclerosis (n=9) was included for exploratory purposes but excluded from the main analysis due to sample size and potential confounding factors related to treatment. All participants provided informed consent, and the study received ethical approval from the Medical University of Plovdiv.

Participants underwent assessment using both the SCCAN-B and the validated Bulgarian version of the Mini-Mental State Examination (MMSE-B). The SCCAN-B comprises eight performance scales: Oral Expression, Orientation, Memory, Auditory Comprehension, Reading Comprehension, Writing, Attention, and Problem Solving. The MMSE-B served as a global cognitive screening measure to assess convergent validity.

Statistical analyses were comprehensive, focusing on:

• Internal Consistency: Evaluating the reliability of the SCCAN-B scales using Cronbach’s alpha.
• Convergent Validity: Examining the correlation between SCCAN-B scores and MMSE-B scores using Spearman’s rank-order correlations.
• Known-Groups Differences: Assessing the ability of the SCCAN-B to differentiate between the neurotypical control group and the clinical neurological groups using the Kruskal-Wallis H test and post-hoc pairwise comparisons.
• Preliminary Screening Utility: Employing Receiver Operating Characteristic (ROC) analysis to determine the SCCAN-B’s effectiveness in distinguishing between controls and clinical groups, including calculating the area under the curve (AUC) and identifying potential cut-off scores.

Key Findings: Promising Psychometric Properties

The results of the study indicate that the SCCAN-B exhibits strong psychometric properties, suggesting its potential as a valuable clinical tool.

• High Internal Consistency: The SCCAN-B demonstrated excellent internal consistency across its eight performance scales, with an overall Cronbach’s alpha of 0.931. This indicates that the scales are reliably measuring the same underlying construct. Correlations between individual performance scales and the SCCAN-B total score were significant and generally strong, with Memory, Attention, Oral Expression, and Problem Solving showing particularly high associations.

• Strong Convergent Validity: A robust positive correlation (r_s = 0.840, p < 0.001) was found between the SCCAN-B total score and the MMSE-B scores. This suggests that the SCCAN-B aligns well with a widely used global cognitive screening measure, supporting its convergent validity. The strongest correlations with the MMSE-B were observed for Memory, Oral Expression, Attention, Orientation, and Problem Solving scales.

• Significant Group Differences: The Kruskal-Wallis H test revealed statistically significant differences in SCCAN-B total scores and all individual performance scales across the four main groups. As anticipated, individuals with Alzheimer’s disease exhibited the most severe impairments, scoring significantly lower than all other groups. Participants with mild cognitive impairment and ischemic stroke also showed significantly lower scores compared to neurotypical controls. The memory scale, in particular, showed the largest between-group differences, highlighting its sensitivity to cognitive decline. The effect size estimates (eta-squared) were large to moderate across most scales, indicating clinically meaningful differences beyond statistical significance.

• Preliminary Screening Accuracy: ROC analysis indicated that the SCCAN-B has good preliminary classification performance in distinguishing between controls and the combined clinical groups, with an Area Under the Curve (AUC) of 0.850. A preliminary total score cut-off of 80 was identified, yielding 70.7% sensitivity and 87.1% specificity in this sample. This suggests that a score below 80 might indicate a higher likelihood of cognitive-communicative difficulties, warranting further investigation.

Performance Patterns Across Neurological Conditions

The study’s findings provide initial insights into the cognitive-communicative profiles of different neurological conditions within the Bulgarian population.

• Neurotypical Controls: Consistently demonstrated high scores across all SCCAN-B domains, reflecting intact cognitive-communicative functioning.

• Mild Cognitive Impairment (MCI): Participants with MCI showed intermediate performance levels. While orientation, writing, and auditory comprehension remained relatively preserved, deficits were most pronounced in memory and attention. This pattern aligns with the understanding of MCI as a transitional stage where specific cognitive functions begin to decline.

• Alzheimer’s Disease (AD): The AD group exhibited the most severe and widespread impairments. Memory, orientation, oral expression, attention, and problem-solving were significantly affected. These findings are consistent with the known progression of AD, where memory and executive functions are typically impacted early.

• Ischemic Stroke: The performance profile of the ischemic stroke group was more heterogeneous, likely reflecting the varied nature of stroke lesions. Orientation and oral expression were relatively preserved, while attention and problem-solving showed greater deficits. The exclusion of individuals with severe aphasia may have contributed to the relative preservation of language-related scores in this group.

The study emphasizes that while these patterns are broadly consistent with international findings, they are preliminary. The heterogeneity within clinical groups, particularly the stroke group, and the modest sample sizes limit definitive disorder-specific interpretations.

Clinical Implications and Future Directions

The development of the SCCAN-B holds significant promise for Bulgarian clinical practice. It offers clinicians a standardized tool to:

• Identify Cognitive-Communicative Difficulties: The instrument can help pinpoint specific areas of cognitive-communicative impairment in individuals with neurological disorders.
• Profile Strengths and Weaknesses: It allows for a detailed description of relative strengths and weaknesses across multiple cognitive-communication domains.
• Support Referral and Rehabilitation Planning: The comprehensive profiles generated by the SCCAN-B can inform referral decisions for specialized assessments and guide the development of individualized rehabilitation plans.
• Enhance Interdisciplinary Communication: Standardized assessment results can improve communication and collaboration among neurologists, speech-language pathologists, neuropsychologists, and other rehabilitation professionals.

The preliminary cut-off score of 80 for the SCCAN-B total score may serve as a useful indicator for identifying individuals who might benefit from further, more in-depth cognitive-communicative or neuropsychological evaluation. However, researchers and clinicians are cautioned that this cut-off is preliminary and requires validation in larger, more diverse Bulgarian populations.

The successful adaptation and preliminary validation of the SCCAN-B underscore the feasibility of developing culturally relevant assessment tools for Bulgarian-speaking populations. However, further research is essential to solidify its clinical utility. Future studies should focus on:

• Normative Data: Establishing age- and education-stratified normative data for the Bulgarian population.
• Test-Retest and Interrater Reliability: Evaluating the consistency of SCCAN-B scores over time and across different administrators.
• Broader Validation: Comparing SCCAN-B performance with a wider range of neuropsychological assessments, communication-specific instruments, and functional outcome measures (e.g., Instrumental Activities of Daily Living).
• Longitudinal Studies: Investigating the SCCAN-B’s ability to monitor disease progression, track rehabilitation effects, and assess changes in functional communication over time.
• Disorder-Specific Profiles: Conducting larger, multicenter studies with diagnostically homogeneous samples to confirm disorder-specific performance patterns.

Limitations and Cautious Interpretation

The authors acknowledge several limitations in the current study that necessitate cautious interpretation of the findings. The modest sample size, particularly within the MCI group, limits statistical power and the stability of cut-off estimates. The convenience sampling method, drawing participants from a single tertiary university hospital, means the results may not be generalizable to the broader Bulgarian population.

The clinical heterogeneity within the groups, especially the stroke cohort, where factors like lesion location, aphasia severity, and handedness were not systematically analyzed, also warrants consideration. The fixed order of test administration, while ensuring consistency, means potential order effects or fatigue cannot be entirely ruled out. Furthermore, standardized measures of psychological factors such as depression, anxiety, and fatigue were not included, which could influence cognitive and communicative performance.

The reliance on the MMSE-B as the sole external cognitive comparison measure is also noted. While validated and widely used in Bulgaria, it does not provide the detailed assessment of cognitive-communicative abilities that the SCCAN-B offers.

Conclusion: A Promising Tool for Bulgarian Neurorehabilitation

In conclusion, this preliminary validation study provides encouraging evidence for the SCCAN-B as a promising screening and profiling instrument for Bulgarian-speaking adults with neurological disorders. Its high internal consistency, strong correlation with the MMSE-B, and ability to differentiate between neurotypical and clinical groups suggest its potential to significantly enhance the assessment of cognitive-communicative abilities in Bulgaria. The identified preliminary cut-off score offers a potential starting point for clinical screening.

However, the findings are preliminary and do not constitute full normative standardization. Larger, multicenter studies with representative samples and comprehensive psychometric evaluations are crucial to confirm the SCCAN-B’s reliability, validity, and clinical utility. The ongoing development and validation of such culturally adapted instruments are vital for improving diagnostic accuracy, optimizing treatment planning, and ultimately enhancing the quality of life for individuals affected by neurological disorders in Bulgaria.