STAD is a brief screening assessment designed to help clinicians identify possible aphasia, dysarthria, and related cognitive dysfunction following brain injury.
It consists of 29 items across three domains—Language, Speech, and Nonverbal Assessment—and takes approximately 10 minutes to administer.
STAD is not intended to provide a definitive diagnosis. Instead, it offers an initial overview of communication function to guide further assessment and rehabilitation planning.
This page presents the basic specifications of STAD, including its standardization study, reliability, validity, screening accuracy, and important considerations for clinical use.
Basic Information
| Item | Details |
|---|---|
| Official Name | Screening Test for Aphasia and Dysarthria |
| Abbreviation | STAD |
| Purpose | Initial assessment of communication functions following brain injury |
| Target Population | Individuals suspected of having aphasia or dysarthria following brain injury such as stroke |
| Assessment Domains | Language Assessment, Speech Assessment, Nonverbal Assessment |
| Number of Items | 30 items |
| Administration Time | Approximately 9 minutes 48 seconds |
| Assessment Form | One A4-size sheet |
| Primary Users | Healthcare professionals involved in assessing communication disorders following brain injury, including speech-language pathologists |
| Clinical Positioning | Screening and initial assessment prior to comprehensive evaluation |
The administration time may vary depending on the patient’s severity, level of alertness, attention function, motor function, hearing ability, visual ability, and other clinical factors.
Three Assessment Domains of STAD
The Language Assessment evaluates language functions associated with aphasia, including comprehension and verbal expression.
In addition to test scores, clinicians observe response patterns, types of errors, response latency, and the presence or absence of self-correction behaviors.
The Speech Assessment evaluates speech functions associated with dysarthria, including phonation, articulation, speech rate, and speech rhythm.
Assessment includes not only speech intelligibility but also voice quality, articulatory accuracy, and changes in speech rate and rhythm.
The Nonverbal Assessment evaluates cognitive functions related to test performance and communication, including orientation and imitation of movements.
The Nonverbal Assessment is not designed to provide a comprehensive evaluation of higher brain dysfunction. When responses indicate possible impairment, additional assessments related to attention, cognition, praxis, and visuospatial abilities should be considered.
Standardization Study
For the Japanese version of STAD, data were collected from 222 healthy adults. Based on analyses of score distributions and the influence of factors such as age, standardized evaluation criteria were established.
Standardization data provide important references for interpreting patient performance. However, scores may be influenced by various factors, including:
- Age
- Educational background
- Sensory functions
- Motor functions
- Level of alertness
- Fatigue
- Testing environment
Therefore, STAD results should not be interpreted solely through comparison with reference values.
Multicenter Collaborative Study
To evaluate the clinical utility and test characteristics of STAD, a multicenter prospective collaborative study was conducted across 20 institutions throughout Japan.
In this study, STAD was administered to 314 individuals with brain injuries, and relationships between STAD performance, detailed assessments of aphasia, dysarthria, nonverbal functions, and clinical findings were examined.
Among these participants, 212 individuals underwent additional detailed assessments, including the Western Aphasia Battery (WAB) and comprehensive evaluations of dysarthria, allowing analysis of the relationship between STAD domains and established assessment measures.
Study Overview
| Item | Details |
|---|---|
| Study Design | Multicenter prospective collaborative study |
| Participating Institutions | 20 institutions nationwide |
| Participants Assessed with STAD | 314 individuals with brain injuries |
| Participants Receiving Detailed Assessments | 212 individuals |
| Main Evaluation Areas | Score distribution, reliability, criterion-related validity, screening accuracy |
| External Reference Measures | Western Aphasia Battery (WAB), Assessment of Motor Speech for Dysarthria (AMSD), and clinical findings |
Reliability
The internal consistency of each STAD domain was examined using Cronbach’s alpha coefficient, an indicator of reliability.
| STAD Domain | Cronbach’s α |
|---|---|
| Language Assessment | 0.90 |
| Speech Assessment | 0.78 |
| Nonverbal Assessment | 0.68 |
The Language Assessment and Speech Assessment demonstrated acceptable internal consistency.
The Nonverbal Assessment consists of a small number of items evaluating different types of functions, such as orientation and imitation of movements. Therefore, interpretation should not rely solely on the total score. The characteristics of responses in individual items should also be considered.
Criterion-Related Validity
The relationships between each STAD domain and corresponding comprehensive assessment measures were examined.
| STAD Domain | Reference Assessment | Correlation Coefficient |
|---|---|---|
| Language Assessment | WAB Aphasia Quotient | r = 0.89 |
| Speech Assessment | AMSD | r = 0.70 |
| Nonverbal Assessment | WAB Nonlinguistic Skills (WAB NLS) | r = 0.79 |
The Language Assessment demonstrated a strong correlation with the WAB Aphasia Quotient.
The Speech Assessment and Nonverbal Assessment also demonstrated moderate to strong correlations with their corresponding reference assessments.
These findings support that each STAD domain reflects the communication function it is designed to assess.
Screening Accuracy
In the multicenter collaborative study, cutoff values were examined for each STAD domain to identify the possibility of impairment.
The domain-specific analyses demonstrated the following screening performance:
- Sensitivity: 82–92%
- Specificity: 77–78%
Sensitivity refers to the proportion of individuals with the target impairment who are correctly identified by the assessment.
Specificity refers to the proportion of individuals without the target impairment who are correctly identified as not having the impairment.
STAD cutoff criteria were established by considering the balance between sensitivity and specificity, supporting its use as a screening tool for identifying individuals who may require further assessment.
For detailed cutoff values and scoring procedures, please refer to the STAD assessment manual.
Interpretation of STAD Results
STAD results should be interpreted not only based on the total score, but also by considering performance across the three assessment domains—Language Assessment, Speech Assessment, and Nonverbal Assessment—as well as the characteristics of responses in individual items.
A score below the cutoff value suggests the possibility of impairment in the corresponding functional area.
However, a score below the cutoff value does not confirm a diagnosis of aphasia or dysarthria.
Conversely, even when a score is above the cutoff value, mild impairments may become apparent through subsequent neuropsychological assessments or behavioral observations.
STAD results should be interpreted comprehensively together with the following information:
- Time since onset or injury
- Neurological findings
- Brain imaging findings
- Behavioral observations during daily conversation and inpatient activities
- Information obtained from patients and their families
- Results of standardized comprehensive assessments
- Assessment conditions, including alertness, attention, fatigue, and motivation
What STAD Can Assess
STAD can be used for the following purposes:
- Obtain an overview of communication functions following brain injury within a short period of time
- Identify the possibility of aphasia or dysarthria
- Determine which domains—language, speech, or nonverbal functions—may require further evaluation
- Select appropriate comprehensive assessments for further investigation
- Obtain information to support early rehabilitation planning
- Share assessment perspectives among different speech-language pathologists
- Organize key perspectives for initial assessment in clinical education and training settings
What STAD Cannot Assess Alone
STAD is a screening assessment and is not intended to independently perform the following:
- Establish a definitive diagnosis of aphasia or dysarthria
- Classify the type or severity of aphasia in detail
- Determine the neurological subtype of dysarthria
- Provide a comprehensive evaluation of all higher brain functions
- Automatically determine the content or frequency of rehabilitation
- Fully assess communication abilities in daily life situations
When STAD suggests a possibility of impairment, additional comprehensive assessments and behavioral observations should be conducted according to the clinical purpose.
Clinical Considerations
Influence of Assessment Conditions
STAD results may be influenced by various factors, including:
- Level of consciousness and alertness
- Attention function
- Fatigue
- Pain
- Hearing impairment
- Visual impairment
- Paralysis
- Apraxia
- Emotional state
- Medication effects
When scores are low, clinicians should consider whether factors other than the target communication disorder may have affected performance.
Assessment of Mild Cases
In individuals with mild aphasia or dysarthria, communication difficulties may not always be clearly identified through a brief screening assessment.
When patients or family members report communication difficulties, or when clinical observation suggests possible impairment, further comprehensive assessment should be considered regardless of the STAD score.
Evaluation of Changes Over Time
During the acute phase following brain injury, assessment results may change as alertness and overall medical condition improve.
Clinical decisions should not be based solely on a single assessment result.
When necessary, repeated assessments should be conducted to evaluate changes over time.
Comprehensive Clinical Judgment
STAD is not intended to replace the clinical judgment of speech-language pathologists.
It should be used as part of a comprehensive clinical decision-making process by integrating:
- STAD scores
- Error patterns
- Behavioral observations
- Medical information
- Results from comprehensive assessments
The goal is to develop a complete understanding of each individual’s condition.
Related Publications
Main STAD Publication
Araki K, Hirano Y, Kozono M, Fujitani J, Shimizu E.
The Screening Test for Aphasia and Dysarthria (STAD) for Patients with Neurological Communicative Disorders: A Large-Scale, Multicenter Validation Study in Japan.
Folia Phoniatrica et Logopaedica.
2022;74(3):195–208.
doi:10.1159/000519381
For additional publications, conference presentations, and research achievements related to STAD, please refer to the research achievements section of the Developer Profile.
Screening Forms & Manual
To properly administer STAD and accurately interpret assessment results, please review the STAD assessment manual.
The manual includes information on:
- Assessment preparation
- Administration procedures
- Scoring criteria
- Cutoff values
- Interpretation of results
- Important considerations for clinical use