The Trunk Impairment Scale<\/strong> (TIS) is a clinician-rated performance measure developed by KU Leuven<\/a> researchers (Verheyden et al., 2004) to evaluate motor impairment of the trunk following stroke<\/a> and other central nervous system lesions. The instrument consists of 17 performance items distributed across three conceptually distinct subscales: Static Sitting Balance (3 items; score range 0\u20137), Dynamic Sitting Balance (10 items; score range 0\u201310), and Trunk Coordination (4 items; score range 0\u20136). The cumulative score ranges from 0 to 23, where higher values reflect superior selective trunk control, postural stability, and trunk coordination. Administered in a seated position without back or arm support, the scale emphasizes qualitative aspects of trunk movement, including the presence of selective lateral flexion, pelvic elevation, segmental rotation of the shoulder and pelvic girdles, and the active avoidance of compensatory strategies involving the upper extremities or contralateral lower extremity. Psychometric evaluations demonstrate high inter-rater reliability (intraclass correlation coefficient<\/a> [ICC] = 0.96 to 0.99), test-retest reliability (ICC = 0.85 to 0.96), and internal consistency (Cronbach’s alpha = 0.86 to 0.89). Convergent validity is evidenced through strong correlations with the Berg Balance Scale<\/a>, the Barthel Index<\/a>, and gait speed measures, while predictive validity analyses establish baseline TIS scores as an independent determinant of long-term functional recovery, balance performance, and community ambulation<\/span>.<\/p>\n Trunk Impairment Scale, trunk control, sitting balance, stroke rehabilitation, postural stability, neurorehabilitation, psychometrics, motor impairment, core stability, physical therapy<\/p>\n The Trunk Impairment Scale was created and validated by an interdisciplinary neurorehabilitation research group at the Department of Rehabilitation Sciences, Faculty of Kinesiology and Rehabilitation Sciences, Katholieke Universiteit Leuven<\/a> (KU Leuven), Belgium.<\/p>\n The primary purpose of the Trunk Impairment Scale is to provide a standardized, psychometrically sound, and clinically feasible assessment of trunk motor impairment in patients suffering from acute, subacute, or chronic neurological insults. Historically, neurological examinations in physical therapy and physiatry focused predominantly on upper and lower extremity motor control (such as the Fugl-Meyer Assessment), frequently treating the axial skeleton and trunk musculature as a secondary or passive biomechanical link. However, contemporary neurophysiology demonstrates that the trunk constitutes the foundational anchor for balance, functional extremity reach, postural adjustments, and safe ambulation.<\/p>\n Clinically, the TIS serves three critical roles:<\/p>\n The scale was developed specifically for post-stroke hemiparesis, but its application has systematically expanded across neurorehabilitation research to encompass multiple sclerosis<\/a>, Parkinson’s disease<\/a>, traumatic brain injury, and spinal cord injuries where axial sensorimotor disruption limits functional independence.<\/p>\n The Trunk Impairment Scale operationalizes the multi-faceted construct of trunk performance<\/em> within the context of seated postural control. Sitting requires the integration of vestibular, somatosensory, and visual inputs transformed into anticipatory and reactive neuromotor activation patterns across the multi-segmented spinal column, ribcage, and pelvis. The scale breaks this complex sensorimotor construct into three distinct, hierarchical dimensions:<\/p>\n Static sitting balance assesses the participant’s intrinsic capacity to maintain a neutral, upright vertical posture against gravity without external support, both under unperturbed conditions and during self-induced or externally induced biomechanical perturbations. This dimension reflects the basic integrity of tonic postural muscle activation, verticality perception, and midline orientation. For instance, the first item evaluates basic unassisted maintenance of upright posture for 10 seconds. The subsequent two items systematically introduce asymmetrical base-of-support alterations (passively and then actively crossing the non-paretic lower extremity over the paretic lower extremity). Maintaining equilibrium under these narrowed and elevated base-of-support conditions demands rapid baseline recalibration of vestibulospinal and reticulospinal pathways, intact weight-shift acceptance onto the hemiplegic ischial tuberosity, and unilateral trunk stabilization against rotational torques.<\/p>\n Dynamic sitting balance captures the participant’s ability to selectively execute active lateral trunk flexion excursions and pelvic movements within the frontal plane while preserving seated equilibrium and avoiding falls. This dimension assesses active elongation on the weight-bearing side coupled with selective shortening (concentric contraction of the lateral abdominal wall, including the obliquus internus abdominis, obliquus externus abdominis, and quadratus lumborum) on the non-weight-bearing side. Crucially, the construct differentiates between true selective lateral trunk movement and pathological multi-joint compensatory synergies. In neurological disorders, patients frequently substitute active trunk flexion by pushing off with an intact arm, throwing the shoulder backwards into extension, or lifting the contralateral foot off the floor. The dynamic subscale explicitly penalizes these compensatory patterns by scoring both the execution of the primary movement (reaching the elbow to the plinth or elevating the hemi-pelvis) and the selective absence of secondary biomechanical substitutions.<\/p>\n The coordination dimension operationalizes the selective dissociation between the upper trunk (shoulder girdle) and the lower trunk (pelvic girdle) along the transverse plane. Rotational dissociation is an essential prerequisite for biomechanically efficient human locomotion, reciprocal arm swing, and spontaneous reach-to-grasp behaviors. The TIS evaluates whether an individual can selectively rotate the thoracic region while the pelvic girdle remains stationary, and conversely, whether they can rotate the pelvis while maintaining a stationary thoracic girdle. Furthermore, this dimension assesses the temporal rhythm and velocity of motor control by requiring the performance of six complete alternating cycles within a strict temporal threshold (six seconds), capturing motor coordination, symmetry, and movement fluency.<\/p>\n The conceptual architecture of the Trunk Impairment Scale is grounded in the Systems Approach to Motor Control<\/strong> (Bernstein, 1967<\/a>; Shumway-Cook & Woollacott, 2012<\/a>) and the kinesiological principles of neurodevelopmental therapy (Bobath concept<\/a>).<\/p>\n Under Bernstein’s systems model, motor behavior is not merely the readout of pre-programmed motor engrams; rather, it emerges from dynamic, non-linear interactions between the neuromuscular system, external gravitational forces, and task demands. The central nervous system faces the fundamental challenge of managing abundant degrees of freedom across the 24 mobile vertebrae, 23 intervertebral discs, and complex multi-layered axial musculature. In healthy motor control, the central nervous system controls these degrees of freedom through coordinative structures (muscle synergies). Following upper motor neuron lesions, selective cortical control is impaired, leading to abnormal co-activation, hypertonia, weakness, and stereotyped mass synergies. The theoretical basis of the TIS rests on the premise that selective trunk control\u2014specifically the ability to dissociate pelvic movement from scapular movement, and lateral flexion from sagittal flexion\u2014is a prerequisite for functional movement of the appendicular skeleton.<\/p>\n Additionally, the scale incorporates the neurophysiological concept of Anticipatory Postural Adjustments (APAs)<\/strong>. Postural control is not exclusively reactive; whenever an individual plans to reach, step, or turn the head, feedforward postural commands activate the transversus abdominis, internal oblique, and deep spinal stabilizers (multifidi) milliseconds prior to prime-mover activation. When static or dynamic trunk control is compromised, feedforward stability is lost, forcing the individual into rigid fixation strategies (such as clutching the bed or locking the shoulder girdle) to prevent loss of balance. The TIS evaluates whether these fundamental postural mechanisms are preserved, disrupted, or compensated for by maladaptive postural strategies.<\/p>\n The psychometric properties of the Trunk Impairment Scale have been investigated across dozens of peer-reviewed clinical studies worldwide, confirming strong construct, convergent, discriminant, and predictive validity.<\/p>\n Verheyden et al. (2004) initially established construct validity by demonstrating that the TIS effectively discriminates between healthy age-matched control participants and individuals with stroke. Healthy adults universally attain maximum scores (23\/23), while individuals with acute and chronic hemiparesis display widely dispersed scores correlating directly with clinical impairment severity. Subsequent investigations have demonstrated the scale’s capacity to discriminate between individuals with mild, moderate, and severe stroke as stratified by the National Institutes of Health Stroke Scale (NIHSS) and the Fugl-Meyer motor assessment.<\/p>\n Convergent validity has been established against gold-standard functional and balance metrics:<\/p>\n Prospective cohort studies have examined the prognostic utility of early TIS administration. Verheyden and colleagues demonstrated that TIS scores obtained during the first two to four weeks post-stroke explain a significant proportion of the variance in discharge destination (home vs. nursing facility), long-term functional independence, and attainment of community ambulation status at 6 months post-stroke, even after controlling for age, initial limb motor scores, and lesion volume.<\/p>\n The Trunk Impairment Scale demonstrates excellent clinimetric reliability across varied clinical settings, languages, and neurorehabilitation contexts.<\/p>\n In the original validation study by Verheyden et al. (2004) involving stroke patients evaluated simultaneously by independent physical therapy raters, the intraclass correlation coefficient (ICC)<\/strong> for the total TIS score was 0.99<\/strong> (95% confidence interval [CI]: 0.98\u20131.00). Subscale inter-rater reliability values were similarly robust:<\/p>\n Individual item agreement evaluated via Cohen’s kappa<\/a> (κ) and weighted kappa (κw<\/sub>) ranged from 0.62 to 1.00, representing substantial to almost perfect rater agreement according to Landis and Koch criteria.<\/p>\n Test-retest stability assessed over intervals spanning 48 hours to 7 days yielded total score ICCs between 0.85 and 0.96<\/strong>. Studies evaluating the Standard Error of Measurement (SEM)<\/strong> and Minimal Detectable Change (MDC)<\/strong> indicate that the SEM for the total TIS score ranges between 0.87 and 1.30 points, yielding an MDC at the 95% confidence level (MDC95<\/sub>) of approximately 2.4 to 3.6 points<\/strong>. Clinicians can therefore conclude with 95% confidence that an observed improvement of 3 points or greater on the 23-point scale reflects true physiological motor recovery beyond measurement error.<\/p>\n Internal consistency analyses across diverse neurorehabilitation cohorts have confirmed high overall reliability. Cronbach’s alpha for the composite 17-item scale typically falls between α = 0.86 and 0.89<\/strong>. Subscale alpha coefficients are highest for the Dynamic Sitting Balance subscale (α = 0.83 to 0.88), while the Coordination subscale demonstrates moderate internal consistency (α = 0.68 to 0.74), reflecting the specialized, multi-directional nature of rotation dissociation<\/span>.<\/p>\n The structural dimensionality of the Trunk Impairment Scale has been examined using Exploratory Factor Analysis (EFA), Confirmatory Factor Analysis (CFA), and Rasch Measurement Theory<\/a>.<\/p>\n Initial structural modeling supported the tripartite organization of Static Sitting Balance, Dynamic Sitting Balance, and Trunk Coordination. In confirmatory structural models, the three-factor solution demonstrated adequate model fit:<\/p>\n Item factor loadings across all three intended domains consistently exceed λ = 0.65, with dynamic items demonstrating particularly high loadings (λ = 0.74\u20130.91) on the central trunk control latent construct<\/span>.<\/p>\n Subsequent psychometric investigations utilizing modern Item Response Theory (IRT) and Rasch analysis (notably by Franchignoni et al., 2009, and Verheyden et al., 2006) revealed structural nuances within the original instrument. Rasch partial credit modeling indicated that the Static Sitting Balance<\/strong> subscale displays a pronounced Guttman-like ceiling effect in subacute stroke patients who possess basic ambulatory or seated independence; patients who can sit independently frequently score maximum points (7\/7) on Static items, leading to local item dependency and poor targeting at the higher end of recovery.<\/p>\n Furthermore, Rasch diagnostic indices highlighted redundant item thresholds within the paired compensation items of the dynamic subscale. These empirical findings motivated the formulation of a modified, shortened 10-item unidimensional scale known as the Trunk Impairment Scale 2.0<\/em> (TIS 2.0 or modified TIS), which eliminated the static subscale and streamlined items into dynamic sitting balance and trunk coordination. Nevertheless, the original 17-item, 23-point TIS remains the most widely cited and comprehensively benchmarked trunk assessment scale in global neurorehabilitation literature and clinical trials.<\/p>\n The Trunk Impairment Scale was published in 2004<\/strong> by Geert Verheyden and colleagues at KU Leuven in the Clinical Rehabilitation<\/em> journal. The instrument is considered open-access for non-commercial clinical, educational, and academic research purposes<\/strong>. Physical therapists, neurologists, occupational therapists, and clinical researchers may utilize the scale without purchasing licensing fees, provided that appropriate scholarly attribution is accorded to the original developers (Verheyden et al., 2004). Commercial distributions, software digitization within proprietary electronic medical record systems, or inclusion in fee-for-service testing batteries may require explicit written authorization from the copyright holders and KU Leuven Research & Development.<\/p>\n The Trunk Impairment Scale (TIS) is a standardized clinician-rated performance assessment evaluating static sitting balance, dynamic sitting balance, and trunk coordination in post-stroke hemiparesis and neurological rehabilitation.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","template":"","categories":[7943,5138,5205],"tags":[7948,5622,7947,7946,899,3310,7945,7944,7949],"class_list":["post-2016","psych_scale","type-psych_scale","status-publish","hentry","category-motor-control-scales","category-neurological-assessment","category-physical-therapy-rehabilitation","tag-ku-leuven","tag-neurorehabilitation","tag-postural-stability","tag-sitting-balance","tag-stroke-rehabilitation","tag-tis","tag-trunk-control","tag-trunk-impairment-scale","tag-verheyden"],"_links":{"self":[{"href":"https:\/\/ashadocs.org\/index.php?rest_route=\/wp\/v2\/psych_scale\/2016","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ashadocs.org\/index.php?rest_route=\/wp\/v2\/psych_scale"}],"about":[{"href":"https:\/\/ashadocs.org\/index.php?rest_route=\/wp\/v2\/types\/psych_scale"}],"author":[{"embeddable":true,"href":"https:\/\/ashadocs.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ashadocs.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2016"}],"version-history":[{"count":0,"href":"https:\/\/ashadocs.org\/index.php?rest_route=\/wp\/v2\/psych_scale\/2016\/revisions"}],"wp:attachment":[{"href":"https:\/\/ashadocs.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2016"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ashadocs.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2016"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ashadocs.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2016"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Keywords<\/h2>\n
Authors<\/h2>\n
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Purpose<\/h2>\n
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Psychological and Neuromotor Construct<\/h2>\n
1. Static Sitting Balance<\/h3>\n
2. Dynamic Sitting Balance<\/h3>\n
3. Trunk Coordination<\/h3>\n
Theoretical Framework<\/h2>\n
Validity<\/h2>\n
Construct and Discriminant Validity<\/h3>\n
Convergent and Concurrent Validity<\/h3>\n
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Predictive Validity<\/h3>\n
Reliability<\/h2>\n
Inter-Rater and Intra-Rater Reliability<\/h3>\n
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Test-Retest Reliability and Measurement Error<\/h3>\n
Internal Consistency<\/h3>\n
Factor Analysis and Structural Equation Modeling<\/h2>\n
Confirmatory Factor Analysis (CFA)<\/h3>\n
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Rasch Analysis and Modern Clinimetric Critiques<\/h3>\n
Instrument \/ Measurement Tool<\/h2>\n
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Permissions & Fee and Test Year<\/h2>\n
References<\/h2>\n
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13. Items of the Scale (Questionnaire)<\/h2>\n