Modified Postural Assessment Scale for Stroke

Abstract

The Modified Postural Assessment Scale for Stroke (mPASS) is a clinical performance measure designed to evaluate postural control and balance abilities specifically in patients who have suffered a stroke. It comprises 12 items rated on a 4-point ordinal scale. The assessment covers a comprehensive range of activities, including both static balance (e.g., sitting unsupported, standing still, standing on the affected leg) and dynamic balance (e.g., transitions from supine to side-lying, sit-to-stand, and reaching for an object while standing). The mPASS is an adaptation of the original Postural Assessment Scale for Stroke (PASS). Key differences from measures like the Berg Balance Scale (BBS) include the specific testing of both the affected and non-affected lower extremity, and the inclusion of transfers while lying, making the mPASS suitable even for patients exhibiting a low functional level.

Keywords

Stroke, Modified Postural Assessment Scale for Stroke, mPASS, Balance, Postural Control, Mobility, Performance Measure, Berg Balance Scale, Rehabilitation.

Authors

Persson CU, et al. (2011); Dutch Version: Brouwer R (2019)

Purpose

The primary purpose of the Modified Postural Assessment Scale for Stroke (mPASS) is to provide clinicians and researchers with a standardized, reliable, and sensitive tool for quantifying changes in balance and postural stability over time in individuals following a stroke. Its design is tailored to capture subtle improvements or declines across various functional levels, particularly focusing on the specific motor impairments commonly observed in stroke survivors.

Unlike some broader mobility scales, the mPASS is structured to assess the patient’s ability to maintain and shift posture during challenging tasks, including those requiring specific loading of the paretic (affected) and non-paretic limbs. This specificity makes it a highly relevant measure for guiding physical therapy interventions aimed at improving functional recovery and preventing falls.

Construct

The core construct measured by the mPASS is Postural Control, defined as the ability to control the body’s position in space for the dual purposes of stability and orientation. The scale breaks this construct down into two main domains: Static Balance and Dynamic Balance.

• Static Balance: This domain assesses the capacity to maintain a stable position against gravity without significant movement, such as maintaining a sitting or standing posture unsupported.
• Dynamic Balance and Transfers: This domain assesses the ability to move the center of mass over the base of support during transitional movements, including moving from lying to sitting, sitting to standing, and performing functional reaching tasks. The inclusion of lying transfers differentiates it from scales like the Berg Balance Scale, ensuring comprehensive coverage of patients with severe mobility impairments.

Validity

The original Postural Assessment Scale for Stroke (PASS), upon which the mPASS is based, has demonstrated strong psychometric properties. Studies examining the validity of the PASS and subsequent mPASS often focus on concurrent validity, showing high correlations with established measures of mobility and functional independence, such as the Fugl-Meyer Assessment and the Functional Independence Measure (FIM).

Content validity is ensured by the selection of 12 items that directly reflect essential static and dynamic postural tasks necessary for daily function in stroke survivors. The modifications introduced in the mPASS version (Persson CU, et al., 2011) were primarily aimed at enhancing clarity and standardizing administration, thereby strengthening the face and content validity of the instrument for clinical use.

Reliability

Research supports the high inter-rater reliability and intra-rater reliability of the mPASS, indicating consistency in scoring regardless of the assessor or repeated administration by the same assessor. The 4-point scoring system and clear operational definitions for each item contribute to this consistency. Furthermore, the scale has demonstrated excellent internal consistency, suggesting that all 12 items measure the underlying construct of postural control effectively.

Factor Analysis

Factor analysis studies of the original PASS typically support a two-factor structure, aligning with the conceptual separation of static and dynamic components of balance. While specific factor analysis results for the slightly modified mPASS version (2011) should be referenced in the primary literature (Persson CU, et al.), the structure is intended to maintain this bifactorial model, confirming that the scale effectively measures distinct, yet related, aspects of postural ability in the stroke population.

Instrument

Test Type: Performance (An objective assessment requiring the patient to execute specific motor tasks).

Format: 12 items, scored on a 4-point ordinal scale (ranging from 0 to 3), yielding a maximum total score of 36. Higher scores indicate better postural control and function.

Language Available: Original research language (likely English/Swedish), Dutch version (Brouwer R, 2019), and likely numerous other language translations.

Population Group: Adults and Older Adults.

Age Group: Typically utilized for individuals aged 18 and above, particularly older adults who are most susceptible to stroke.

Population Details: Patients with mobility impairments resulting from a cerebrovascular accident (stroke). Applicable across a wide range of functional abilities, including those with profound deficits.

Test Methodology: The assessor observes the patient performing the 12 prescribed tasks. Scoring is based on the patient’s independence, stability, and speed of execution for each task, according to predefined criteria.

The original PDF explanation form (Toelichtingsformulier) can be downloaded here: mPASS-form.pdf

The original PDF measurement instrument (Meetinstrument) can be downloaded here: mPASS-meetinstr.pdf

Keywords

Postural Assessment, Impairment Level, Mobility, Motor System, Lower Extremity, Functional Assessment, Neurological Assessment, Recovery, Rehabilitation, Cerebrovascular Accident.

Authors

Author ORCID Identifier: Information not provided in the source content.

Affiliation Email addresses: Information not provided in the source content.

Correspondence Address: Information not provided in the source content.

Permissions & Fee and Test Year

The original PASS was developed in the 1990s. The Modified Postural Assessment Scale for Stroke (mPASS) was formally published by Persson CU, et al. in 2011. The Dutch version was established in 2019 by Brouwer R. Generally, clinical performance measures like the mPASS are widely available for use in clinical settings without proprietary fees, though users should consult the primary reference or official licensing bodies regarding reproduction and large-scale distribution.

Reference’s

The primary reference for the Modified Postural Assessment Scale for Stroke (mPASS) is:

• Persson CU, et al. (2011). *Reference for the Modified Postural Assessment Scale for Stroke*. (Specific citation details need to be retrieved from the primary publication, as they were not included in the source data).
• Brouwer R (2019). *Reference for the Dutch Version*. (Specific citation details need to be retrieved from the primary publication).

Items of the Modified Postural Assessment Scale for Stroke

IMPORTANT: The following scale items must be preserved in their original language and must not be changed in any way.

The 12 items assess balance during both statische activiteiten (static activities) and dynamische activiteiten (dynamic activities). Examples of activities assessed include:

• Zitten (Sitting)
• Stil staan (Standing still)
• Staan op het aangedane been (Standing on the affected leg)
• Rugligging naar zijligging (Supine to side-lying)
• Zit naar stand (Sit-to-stand transfer)
• Iets oprapen uit stand (Picking something up from the floor while standing)