Psychometric Properties

GRASSP Version 1

Graded Redefined Assessment of Strength Sensibility and Prehension

Purpose A clinical impairment measure to assess sensorimotor hand function in persons with traumatic cervical spinal cord injuries (C2-T1).
Acronym GRASSP V1
Description Clinical toolkit

Multi-modal test consisting of:

•  3 domains of hand function:
   Strength – 1; Sensibility – 2; Prehension – 2

Five Subtests:

  • Dorsal sensation (3 locations), each scored 0-4 (sum = subtest score, 0-12)
  • Palmar sensation (3 locations), each scored 0-4 (sum = subtest score, 0-12)
  • Strength (10 muscles of arm & hand), motor grade 0-5 for each (sum = subtest total, 0-50)
  • Prehension ability – 3 grasps (cylindrical, lateral key, tip to tip) – each scored 0-4 (sum = subtest score, 0-12)
  • Prehension performance – 6 prehension tasks (pour water from bottle, open jars, pick up and turn key, transfer 9 pegs from board to board, pick up four coins and place in slots, screw four nuts onto bolts – each scored 0-5 (sum = subtest score, 0-30)

All subtest scores given for the left and the right Designed to capture changes in neurological recovery and hand function.

ICF Domain Body Structure, Body Function, Activity
Time to Administer 30 to 45 minutes
Number of Items and Subtests 5 subtests (25 total items) for each hand
Equipment Required GRASSP Kit includes:

  • Minikit of Semmes Weinstein Monofilaments
  • Standardized materials for all Prehension Testing
  • The GRASSP V1 Manual
  • GRASSP Training Video
  • CD with score sheet and graphing program
Training Required Clinical Settings: Clinicians can independently learn how to administer GRASSP with detailed manual and training video. Requires 2 to 3 trials on a patient to refine skills.Research Studies: Recommended to have a general group training to ensure all clinicians working within the study are consistent. This can be done as a discussion or as a formal training session among a group of clinicians.
Cost Per kit – $1250.00 USD
For use in sponsored clinical trials, a licensing agreement is required with the UHN Technology and Transfer Office.Each license is negotiated and cost is based on usage of GRASSP in the trial.
Year of Copyright 2008
Populations Tested Traumatic Cervical Spinal Cord Injury
Standard Error of Measure (SEM) Sensation Right (0-24) 2.88
Sensation Left (0-24) 2.32
Strength Right (0-50) 3.34
Strength Left (0-50) 3.47
Prehension Ability Right (0-12) 0.99
Prehension Ability Left (0-12) 0.98
Prehension Performance Right – (0-30) 2.16
Prehension Performance Left (0-30) 1.93
Minimally Detectable Difference (MDD) Sensation Right (0-24) More than 2 pts
Sensation Left (0-24) More than 2 pts
Strength Right (0-50) More than 5 pts
Strength Left (0-50) More than 5 pts
Prehension Ability Right (0-12) More than 2 pts
Prehension Ability Left (0-12) More than 2 pts
Prehension Performance Right – (0-30) More than 3 pts
Bilateral Strength (0-100) More than 7 pts
Bilateral Dorsal Sensation (0-24) More than 4 pts
Bilateral Palmar Sensation (0-24) More than 4 pts
Bilateral Prehension Ability (0-24) More than 5 pts
Bilateral Prehension Performance (0-24) More than 6 pts
Minimally Clinical Important Difference ASIA A+B mean (95% CI) ASIA C+D mean (95% CI)
Strength 12 (6.3-17.7) 17 (11.4-26.6)
Sensation 0 (-5.5-5.5) 0 (-6.3-6.3)
Prehension Ability 2 (-3.5-7.5) 1 (-5.0-6.0)
Prehension Performance 6 (-2.3-14.3) 12 (2-22)
Cut-off Scores Not Established
Normative Data Not Established
Test Retest Reliability (ICC) Sensation Right (0-24) 0.95
Sensation Left (0-24) 0.86
Strength Right (0-50) 0.98
Strength Left (0-50) 0.98
Prehension Ability Right (0-12) 0.98
Prehension Ability Left (0-12) 0.98
Prehension Performance Right – (0-30) 0.93
Prehension Performance Left (0-30) 0.93
Inter-rater Reliability (ICC) Sensation Right (0-24) 0.84
Sensation Left (0-24) 0.91
Strength Right (0-50) 0.95
Strength Left (0-50) 0.95
Prehension Ability Right (0-12) 0.95
Prehension Ability Left (0-12) 0.95
Prehension Performance Right – (0-30) 0.95
Prehension Performance Left (0-30) 0.96
Internal Consistency Not Established
Criterion Validity
Concurrent (Pearson Correlation Coefficient)
Sensation Total (R + L) 0.57* 0.74* 0.77*
Strength Total (R + L) 0.59* 0.74* 0.76*
Prehension Ability (R + L) 0.63* 0.77* 0.81*
Prehension Performance (R + L) 0.68* 0.79* 0.83*
Construct Validity Sensation & strength subtests of GRASSP compared to sensory (light touch) & motor upper limb items in the International Standards of Neurological Classification of Spinal Cord Injury (ISNCSCI)54% discordance in sensory innervations when assessed with GRASSP due to additional test points included and the increased response levels used in the GRASSP

GRASSP was more sensitive to identifying sensation than INSCSCI

Adequate agreement (kappa coefficient between 0.412-0.511) between the GRASSP(Semmes Weinstein Monofilament) C6, C7, C8 dorsal test locations and ISNCSCI (light touch) – comparison of same test points

53% discordance in motor innervations when assessed with GRASSP due to added motor points in GRASSP and determination of level by most caudal segment in ISNCSCI

Overall the GRASSP is ~50% more sensitive than the ISNCSCI in determining sensory and motor integrity in the upper limb

Content Validity Established through Sensibility Testing (Kalsi-Ryan et. al 2012)
Face Validity Established through Sensibility Testing (Kalsi-Ryan et. al 2012)
Floor/Ceiling Effects Not Established
Responsiveness (SRM)
GRASSP Strength          0.79 – 1.48
Sensation                        0.14 – 0.64
Prehension                      0.50 – 1.03
Considerations -Individuals with sensory level of C5 or above are expected to score 0 on the sensory testing of the GRASSP.-Clinical utility is decreased secondary to cost of GRASSP kit and increased time to complete measure.

-Domains can be used individually or together.

-This battery of tests has been developed through a comprehensive four phase process examining existing measures and identifying best methods for assessing subtle and clinically meaningful changes and how sensory and motor impairments contribute to integrate function.

The GRASSP Research and Design Group have worked very hard to establish the Psychometric Properties of the GRASSP.

Through two large studies one cross sectional and one longitudinal they have established Reliability, Face Construct and Concurrent Validity, Responsiveness, Minimally Detectable Difference, and Minimal Clinical Important Difference.

  • Kalsi-Ryan S et al. The Graded Redefined Assessment of Strength Sensibility and Prehension: reliability and validity. J Neurotrauma. 2012 Mar 20;29(5):905-14.
  • Kalsi-Ryan S et al. Development of the Graded Redefined Assessment of Strength, Sensibility and Prehension (GRASSP): reviewing measurement specific to the upper limb in tetraplegia. J Neurosurg Spine. 2012 Sep;17(1 Suppl):65-76
  • Velstra IM, Curt A, Frotzier A, Abel R, Kalsi-Ryan S, Rietman JS. Changes in Strength Sensibility and Prehension in Acute Cervical Spinal Cord Injury: European Multicenter Responsiveness Study of the GRASSP. Neurorehabil Neural Repair. 15 Jan 2015.
  • Kalsi-Ryan S, Beaton D, Ahn H, Askes H, Drew B, Curt A, Popovic M, Wang J, Verrier M, Fehlings M. Responsiveness, Sensitivity and Minimally Detectable Difference of the Graded and Redefined Assessment of Strength, Sensibility, and Prehension, Version 1.0 (GRASSP V1). J Neurotrauma. 2015 Nov 11.
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