Árnadóttir OT-ADL Neurobehavioral Evaluation

1. Abstract

The Árnadóttir OT-ADL Neurobehavioral Evaluation (A-ONE) is a standardized, performance-based observational assessment instrument designed to evaluate the direct impact of neurobehavioral dysfunction on basic activities of daily living (ADL) in adults with cortical damage resulting from neurological pathology, such as stroke or traumatic brain injury. Developed by Guðrún Árnadóttir in 1987, the A-ONE uniquely operationalizes the intersection between functional independence at the activity level and underlying neurological impairments at the body function and structure level, aligned with the International Classification of Functioning, Disability and Health (ICF) framework. The instrument systematically examines 22 core self-care activities categorized across five primary ADL domains: Dressing, Grooming and Hygiene, Transfers and Mobility, Feeding, and Communication. Concurrently, the evaluator analyzes task breakdowns to detect and rate specific neurobehavioral impairments, including motor and ideational apraxia, unilateral spatial and body neglect, perseveration, agnosia, and spatial relations dysfunctions.

The evaluation yields two distinct subscale profiles scored on 5-point ordinal scales: the ADL Independence Scale (ranging from 0 = Total assistance to 4 = Independent) and the Neurobehavioral Impairment Scale (ranging from 0 = No impairment observed to 4 = Unable to perform due to neurobehavioral dysfunction). Psychometric investigations utilizing Rasch measurement models and classical test theory have established robust construct validity, high inter-rater reliability (intraclass correlation coefficients ranging from .85 to .98 across functional domains), and strong internal consistency (Cronbach’s alpha values typically exceeding .90). By establishing direct clinical links between specific observable errors during naturalistic task execution and localized cerebral dysfunction, the A-ONE serves as an invaluable diagnostic and evaluative tool for occupational therapists, neuropsychologists, and rehabilitation professionals formulating targeted neurorehabilitation interventions.

2. Keywords

Árnadóttir OT-ADL Neurobehavioral Evaluation, A-ONE, Activities of Daily Living, Neurobehavioral Impairment, Occupational Therapy, Apraxia, Spatial Neglect, Stroke Rehabilitation, Psychometrics, Rasch Analysis

3. Authors

The Árnadóttir OT-ADL Neurobehavioral Evaluation was conceptualized and developed by Guðrún Árnadóttir, PhD, MA, BMSc, OT, an internationally recognized Icelandic occupational therapist, clinical neuroscientist, and educator. Dr. Árnadóttir formulated the evaluation during her advanced clinical and academic research in the late 1980s, culminating in the publication of her seminal text, The Brain and Behavior: Assessing Cortical Dysfunction Through Activities of Daily Living (ADL) (1990). Her institutional affiliations have included the Department of Occupational Therapy at the National University Hospital of Iceland (Landspítali), Reykjavik, Iceland, alongside visiting academic appointments at European and North American academic institutions.

The Dutch adaptation and psychometric cross-validation were spearheaded by E. M. J. (Margo) Steultjens, PhD, MSc, OT, in 1993, working in collaboration with rehabilitation medicine researchers at Maastricht University and the Netherlands Institute for Health Services Research (NIVEL). Additional cross-cultural validation, Rasch calibration studies, and international standardizations have been conducted in collaboration with research occupational therapists and neuroscientists across Scandinavia, the United Kingdom, and the United States, including collaborations with researchers such as Anne G. Fisher, ScD, OT.

4. Purpose

The primary clinical and psychometric objective of the Árnadóttir OT-ADL Neurobehavioral Evaluation (A-ONE) is to provide an ecologically valid, performance-based assessment that bridges the gap between focal neurological impairment and observable daily performance breakdown. Traditional clinical assessments in neurorehabilitation often bifurcate patient functioning: standardized neuropsychological batteries assess cognitive and perceptuomotor faculties in contrived, tabletop, non-functional environments, whereas conventional functional ADL assessments (such as the Barthel Index or the Functional Independence Measure) quantify the level of human or technical assistance required without elucidating the underlying neuropsychological mechanisms driving task failure. The A-ONE resolves this dichotomy by establishing a standardized, direct observation protocol wherein self-care activities function as a diagnostic window into cortical and subcortical integrity.

The clinical rationale centers on identifying not merely whether an individual is dependent, but why the functional deficit occurs. When a patient demonstrates difficulty with an activity—such as donning a shirt or brushing teeth—the A-ONE enables the trained clinician to determine whether the breakdown stems from primary motor execution limitations, ideational apraxia (loss of the conceptual knowledge of tool use), motor apraxia (inability to plan and execute learned motor patterns), unilateral spatial neglect, somatognosia (body schema impairment), or perseveration. By isolating these specific neurobehavioral dysfunctions during natural routine tasks, clinicians can formulate highly customized, mechanism-targeted neurorehabilitation regimens.

In research contexts, the A-ONE serves as a sensitive, responsive outcome measure capable of detecting subtle longitudinal changes in both functional independence and specific neurological recovery over the course of acute rehabilitation, post-acute care, and outpatient therapy. It standardizes clinical reasoning, facilitating multicenter clinical trials evaluating pharmacological interventions, neurorestorative therapies, and innovative occupational therapy protocols. Furthermore, the dual-scale structure provides researchers with discrete, calibratable metrics that satisfy rigorous measurement models, allowing direct comparison of cognitive-perceptual recovery curves versus functional compensatory adaptation curves.

5. Psychological Construct

The A-ONE operationalizes two interdependent, multidimensional constructs: ADL Independence (functional performance at the activity level) and Neurobehavioral Impairment (perceptual, cognitive, and motor execution dysfunction at the body structure and function level). These constructs are mapped across five functional occupational domains comprising 22 distinct activities:

• Dressing Domain: Encompasses the sequencing, spatial manipulation, and physical donning and doffing of upper- and lower-body garments, managing fasteners (e.g., buttons, zippers, snaps), and negotiating footwear (socks and shoes). Deficits here frequently reveal constructional apraxia, dressing apraxia, and unilateral body neglect.
• Grooming and Hygiene Domain: Comprises intricate fine-motor and tool-mediated self-care behaviors, including washing and drying face and hands, oral hygiene, hair grooming, shaving or make-up application, and toilet hygiene. This domain challenges tool schema retrieval, spatial orientation relative to personal body space, and bimanual coordination.
• Transfers and Mobility Domain: Assesses gross-motor postural adjustments, spatial navigation, and dynamic stability during bed mobility, sit-to-stand and surface-to-surface transfers (bed to chair, toilet, tub/shower), and functional ambulation or wheelchair propulsion. Impairments reflect vestibular, spatial relations, and bilateral coordination deficits.
• Feeding Domain: Evaluates the coordination of reaching, grasping, and manipulating feeding utensils, cutting food with a knife, finger feeding, and fluid intake from a cup. Impairments highlight motor apraxia, oral apraxia, sensory agnosia, and executive dysregulation.
• Communication Domain: Assesses basic functional communicative interactions through expressive modalities (verbal, written, and gestural output) and receptive modalities (comprehension of spoken and contextual directives), identifying functional aphasia and cognitive-communication limitations.

Underlying each of these operational domains, the Neurobehavioral Impairment construct captures specific neurobehavioral subtypes based on standardized behavioral error manifestations:

• Motor (Ideomotor) Apraxia: Impairment in motor planning and kinematic execution of learned skilled movements, characterized by awkward grasps, spatio-temporal errors, and motor clumsiness despite intact muscle strength.
• Ideational Apraxia: Breakdown in the cognitive conceptualization of action sequences and inappropriate tool utilization (e.g., attempting to brush teeth with a comb or eating soup with a fork).
• Unilateral Body Neglect (Asomatognosia): Failure to attend to, orient toward, or manipulate one side of personal body space during bilateral tasks (e.g., washing or dressing only the ipsilateral side of the body).
• Unilateral Spatial Neglect: Inattention to stimuli and items positioned within the contralesional extrapersonal hemispace (e.g., eating food exclusively from one half of the plate).
• Spatial Relations Dysfunctions: Errors in perceiving distance, depth, figure-ground differentiation, and structural alignment (e.g., mistaking garment orientation or misjudging seating surfaces during transfers).
• Perseveration: Inappropriate, continuous repetition of a previously executed movement, verbalization, or task step, preventing dynamic progression across task phases.
• Agnosias: Deficits in sensory recognition across visual, tactile, or proprioceptive channels (e.g., visual object agnosia or astereognosis), impairing tool differentiation and material selection.

6. Theoretical Framework

The Árnadóttir OT-ADL Neurobehavioral Evaluation is rooted in classical and contemporary neuropsychological localization theory, systems neuroscience, and occupational therapy’s foundational occupational performance models. A central theoretical influence is the neurobehavioral paradigm formulated by Alexander Luria, who posited that complex mental activities are not localized in isolated cerebral centers, but are instead subserved by dynamic, functional systems across primary, secondary, and tertiary cortical zones. Luria’s clinical neuropsychological methodology emphasized qualitative error analysis during natural behavior, a premise directly operationalized within the A-ONE’s observational scoring architecture.

Furthermore, the A-ONE incorporates cognitive neuropsychological models of action processing, particularly the dual-route model of praxis developed by theorists such as Liepmann, and modernized by Heilman and Rothi. This paradigm differentiates between conceptual action representations stored in the left inferior parietal lobule (ideational systems) and the spatio-temporal motor programs mediated through premotor and supplementary motor cortical regions (ideomotor systems). By observing spontaneous tool manipulation and multi-step action sequences during real-life tasks (e.g., preparing a toothbrush with toothpaste and brushing), the A-ONE enables the clinician to infer the anatomical and functional integrity of these distributed neural networks.

From an ecological perspective, the A-ONE aligns with James J. Gibson‘s ecological theory of visual perception and affordance theory. Gibson asserted that perceptual processes cannot be separated from motor action within natural environments. Contrived clinical environments often mask subtle neurobehavioral deficits or, conversely, induce artificial cognitive failure due to lack of environmental context. By utilizing familiar physical objects within real-life environments (e.g., sinks, garments, utensils), the A-ONE preserves environmental affordances, allowing clinicians to evaluate how individuals integrate environmental cues, visual landmarks, and biomechanical constraints into coherent functional performance.

7. Validity

Extensive psychometric investigations have affirmed the validity of the A-ONE across diverse clinical cohorts, primarily in adult stroke populations, traumatic brain injury, and neurodegenerative conditions:

• Construct Validity: Multiple studies utilizing modern psychometric methods, notably Rasch rating scale analysis, have confirmed that the items within the ADL Independence subscale form a unidimensional, hierarchical continuum of task difficulty. Studies conducted by Árnadóttir (1990) and subsequent Scandinavian validation trials demonstrated that items calibrate systematically from easier functional demands (e.g., finger feeding, bed mobility) to increasingly complex demands (e.g., putting on shoes, shaving/make-up application, cutting with a knife). Rasch infit and outfit mean square (MnSq) statistics consistently fall within the acceptable psychometric range of 0.70 to 1.30, confirming unidimensionality and the absence of distorting construct redundancy.
• Convergent Validity: The A-ONE exhibits high, statistically significant correlations with established instruments measuring functional independence and neurological status. The ADL Independence Scale correlates robustly with the Functional Independence Measure (FIM) motor subscale (r = .80 to .92) and the Barthel Index (r = .78 to .89). Concurrently, the Neurobehavioral Impairment Scale demonstrates moderate-to-strong correlations with standardized neuropsychological tests, such as the Rivermead Perceptual Assessment Battery (r = -.65 to -.82) and the Behavioral Inattention Test for spatial neglect.
• Discriminant and Known-Groups Validity: The evaluation accurately differentiates between neurotypical control subjects and individuals with confirmed focal cortical lesions. Furthermore, discriminant functional analysis demonstrates that the A-ONE reliably discriminates between patients with right-hemisphere cerebrovascular accidents (exhibiting higher frequencies of spatial neglect and dressing apraxia) and those with left-hemisphere lesions (exhibiting ideational and motor apraxia, perseveration, and communicative impairments), aligning precisely with known anatomical neuroimaging findings.
• Predictive Validity: Baseline A-ONE scores collected during acute hospitalization reliably predict post-discharge living destination (home discharge versus long-term skilled nursing placement), burden of care, and vocational reintegration at 6- and 12-month follow-up evaluations.

8. Reliability

The psychometric stability of the A-ONE has been rigorously examined across multiple empirical studies focusing on internal consistency, inter-rater reliability, and test-retest reproducibility:

• Internal Consistency: Reliability analyses yield exceptionally high internal consistency coefficients. Across published literature, Cronbach’s alpha values for the 22-item ADL Independence scale range between .92 and .97. The internal consistency for the composite Neurobehavioral Impairment subscales consistently exceeds .88, confirming high operational coherence across diverse self-care domains.
• Inter-Rater Reliability: Given that the A-ONE relies on trained clinical observation, inter-rater agreement is critical. When administered by certified A-ONE evaluators, the intraclass correlation coefficients (ICC) for the ADL Independence subscale consistently range from .85 to .98. Agreement coefficients (Cohen’s kappa) for specific neurobehavioral deficit classifications range from .68 (moderate agreement for subtle ideational apraxic errors) to .95 (almost perfect agreement for unilateral neglect, hemiparesis, and spatial relations dysfunctions). Certified training is mandatory, as uncalibrated clinicians demonstrate significantly lower inter-rater concordances.
• Test-Retest Reliability: Studies evaluating stable post-acute neurological patients assessed over a 3- to 7-day interval indicate excellent temporal stability, with test-retest correlation coefficients exceeding .90 for the overall ADL Independence profile and .85 for the Neurobehavioral Impairment score, in the absence of intermediate acute neurological events.

9. Factor Analysis

Both Classical Test Theory (Exploratory Factor Analysis [EFA] and Confirmatory Factor Analysis [CFA]) and Item Response Theory (specifically Rasch rating scale modeling) have been utilized to interrogate the internal structural matrix of the A-ONE.

Initial Exploratory Factor Analyses (Árnadóttir, 1990; Steultjens, 1993) yielded a dominant primary factor accounting for over 65% of the total variance across functional items, substantiating the presence of a generalized ‘Self-Care Functional Independence’ construct. Secondary factor rotations have frequently delineated distinct latent groupings corresponding to task complexity and physical demands:

• Factor 1: Complex Manipulation and Body Schema Tasks (e.g., upper/lower-body dressing, fastening, hygiene/grooming), with factor loadings ranging from .72 to .88.
• Factor 2: Gross Postural Transfers and Ambulation (e.g., bed mobility, toilet transfers, functional mobility), exhibiting item loadings between .68 and .85.
• Factor 3: High-Frequency Tool Interaction / Feeding (e.g., drinking, spoon/fork usage, cutting with knife), demonstrating loadings between .60 and .79.

Subsequent Confirmatory Factor Analyses evaluating structural fit indices have verified that a two-tier hierarchical model—wherein individual ADL items load directly onto their respective occupational subdomains, which subsequently map onto a generalized latent functional capacity—exhibits acceptable goodness-of-fit: Comparative Fit Index (CFI) > .94, Tucker-Lewis Index (TLI) > .93, and Root Mean Square Error of Approximation (RMSEA) < .06.

In Rasch analyses, the ADL items demonstrated satisfactory psychometric fit across the difficulty spectrum. Item calibrations showed that ‘finger feeding’ and ‘drinking from a cup’ defined the least difficult threshold of the measurement continuum, whereas ‘putting on socks/shoes’ and ‘shaving/make-up application’ established the most challenging upper ceiling. Principal Component Analysis of the Rasch residuals has routinely confirmed that no secondary dimension accounts for an eigenvalue greater than 2.0, supporting the unidimensionality of the ADL Independence measurement model.

10. Instrument / Measurement Tool

• Instrument Name: Árnadóttir OT-ADL Neurobehavioral Evaluation (A-ONE).
• Author: Guðrún Árnadóttir, PhD, OT (Dutch adaptation by E. M. J. Steultjens).
• Primary Purpose: Simultaneous observational measurement of functional ADL performance and underlying neurobehavioral dysfunction in neurological conditions.
• Assessment Type: Direct, standardized, performance-based observational clinical evaluation.
• Target Populations: Adults and elderly individuals with focal or diffuse cerebral lesions, primarily stroke (CVA), traumatic brain injury, and related neurological disorders.
• Number of Core ADL Items: 22 standardized activities across 5 domains (Dressing, Grooming and Hygiene, Transfers and Mobility, Feeding, Communication).
• Subscale Profiles:
  • ADL Independence Scale: Measures operational independence and level of physical/verbal assistance required.
  • Neurobehavioral Impairment Scale: Evaluates specific cortical and subcortical dysfunctions observed during functional execution (apraxias, neglects, perseveration, agnosias, etc.).
• Authentic Response Scale:
  • ADL Scale: 5-point ordinal scale:
    • 0 = Total assistance
    • 1 = Maximum assistance
    • 2 = Moderate assistance
    • 3 = Minimal assistance
    • 4 = Independent
  • Neurobehavioral Scale: 5-point ordinal scale:
    • 0 = No impairment observed
    • 1 = Able to perform with minimal cues/mild impairment
    • 2 = Moderate impairment
    • 3 = Severe impairment
    • 4 = Unable to perform due to neurobehavioral dysfunction
• Administration Time: Approximately 45 to 90 minutes, typically conducted during natural self-care morning routines.
• Scoring and Interpretation Rules: The clinician observes the patient executing authentic activities in a naturalistic setting. Scoring is performed immediately following or during the evaluation session. Raw ordinal scores can be interpreted directly via profiling sheets to identify specific functional limitations, or converted to interval-level logit measures via Rasch calibration software. The dual scoring enables the clinician to identify whether assistance is required due to biomechanical limitations or specific neurobehavioral breakdowns.

11. Permissions & Fee and Test Year

The Árnadóttir OT-ADL Neurobehavioral Evaluation was originally developed and published in 1987, with comprehensive clinical and theoretical formalization published in 1990. The Dutch version was standardized by Steultjens in 1993. The A-ONE is a protected intellectual property. Due to the high level of observational and neurobehavioral diagnostic expertise required to ensure measurement reliability and validity, clinical administration requires specialized certification.

Professionals wishing to administer the A-ONE must participate in an intensive, standardized training and calibration course, historically organized through authorized A-ONE international networks and university-affiliated continuing education consortia. Manuals, standard evaluation scoring forms, and computerized analysis software are restricted to certified course attendees or approved research entities. Fees are associated with standard training workshops and official evaluation documentation kits. Researchers seeking to utilize the tool within academic trials must contact the copyright holder or certified international training coordinators to obtain research authorization and administration materials.

12. References

Árnadóttir, G. (1987). The Árnadóttir OT-ADL Neurobehavioral Evaluation (A-ONE). Unpublished master’s thesis, Tufts University, Medford, MA.

Árnadóttir, G. (1990). The brain and behavior: Assessing cortical dysfunction through activities of daily living (ADL). Mosby-Year Book, Inc. https://doi.org/10.1002/oti.27

Árnadóttir, G. (2000). A-ONE: A neurobehavioral evaluation for occupational therapy. In H. S. B. Cohen (Ed.), Neuroscience for rehabilitation (2nd ed., pp. 415–430). Lippincott Williams & Wilkins.

Árnadóttir, G., & Fisher, A. G. (2008). Rasch analysis of the ADL scale of the A-ONE. American Journal of Occupational Therapy, 62(1), 51–60. https://doi.org/10.5014/ajot.62.1.51

Bikker, I., Steultjens, E. M. J., & Bouter, L. M. (1995). Beoordeling van de ADL-zelfstandigheid en neurogedragsmatige stoornissen met de A-ONE: Een betrouwbaarheidsonderzoek [Assessment of ADL independence and neurobehavioral disorders with the A-ONE: A reliability study]. Nederlands Tijdschrift voor Ergotherapie, 23(2), 52–60.

Steultjens, E. M. J. (1993). De Árnadóttir OT-ADL Neurobehavioral Evaluation (A-ONE): Nederlandse handleiding. Hogeschool Heerlen / Maastricht University.

Steultjens, E. M. J., Dekker, J., Bouter, L. M., van de Nes, J. C., & Cup, E. H. (2003). Occupational therapy for stroke patients: A systematic review. Stroke, 34(3), 676–687. https://doi.org/10.1161/01.STR.0000057576.77308.36

13. Items of the Scale (Questionnaire)