Prospective multicentre validation study of a new standardised version of the 400-point hand assessment

Background Hand rehabilitation needs valid evaluation tools; the 400-point Hand Assessment (HA) is an exhaustive but not standardised tool. The aim of this study was to validate a standardised version of this test. Methods A modified version and a standardised prototype was made for this prospective validation study (four centres, three countries). Psychometric properties studied: reliability (intra-rater and inter-rater, standard error of measurement [SEM], minimum detectable change [MDC],internal consistency); content validity, construct validity with Jebsen Taylor hand function test, QuickDASH, MOS-SF 36 and pain; responsiveness, using an anchor-based approach (ROC curve with area under curve, mean response change) with calculation of MCID. For SEM, MDC and responsiveness, QuickDASH was used for comparison. Results One hundred and seventy-six patients with hand/wrist injuries were included between May 2013 and February 2015. One hundred and seventy were available for final analysis: 67% men; mean age 43.4 ± 13.2 years; both manual and office workers (46, 5% of each); 37% had a hand or wrist fracture. Reliability: ICC intra-rater = 0.967 [0.938–0.982]; inter-rater = 0.868 [0.754–0.932]. Distribution-based approach: for 400-point HA/QuickDASH: SEM = 3.48/4.52, MDC = 9.065/12.53, internal consistency of 400-point HA: Cronbach α = 0.886. Validity: Content validity was good according to COSMIN guidelines. Construct validity: correlation coefficient: Jebsen-Taylor hand function test = − 0.573 [− 0.666–0.464], QuickDASH = − 0.432 at T0 [− 0.545–0.303], − 0.551 at T3 [− 0.648–0.436]; MOS-SF 36 physical component = 0.395 [0.263–0.513]; no correlation with MOS-SF 36 mental component = 0.142 [− 0.009 + 0.286] and pain = − 0.166 [− 0.306 + 0.018]. Responsiveness: Anchor-based approach: AUC Δ400-point HA = 0.666 [0.583–0.749], AUC ΔQuickDASH = 0.556 [0.466–0.646]. MCID (optimal ROC curve cut-off): 6.07 for 400-point HA, − 2.27 for QuickDASH. MCID with mean response change + 12.034 ± 9.067 for 400-point HA and − 8.03 ± –9.7 for QuickDASH. The patient’s global impression of change was only correlated with the Δ400-point HA. Conclusions The 400-point HA standardised version has good psychometric properties. For responsiveness, we propose an MCID of at least 12.3/100. However, these results must be confirmed in other populations and pathologies. Trial registration This study was retrospectively registered into ISCTRN registry (Number ISRCTN25874481) the 07/02/2019.


INTRODUCTION
The assessment of prehension ability, in all its complexity, remains a real challenge. The conventional use of assessments oriented towards measuring one particular aspect of prehension function (articular, muscular, trophic or sensory) only provides a partial and fragmented response to the question of prehension ability.
The "400-POINT Assessment" offers a four-fold evaluation covering motor function, strength, one-handed grasp, and two-handed coordination. The observation of these during approximately 60 everyday movements provides information about prehension quality and means of adaptation. The score awarded to each test "points to" the area of deficit.
A period of 30-45 minutes is needed to carry out this assessment.

12: "Place your hands back to back, with your fingers extending downwards, then raise your elbows towards a horizontal line at chest height."
For exercises 13 and 14 the patient moves away from the table, sitting with their elbows tucked into the body, their forearms at a 90°angle and his thumbs pointing upwards.

Coefficients
Not all of these exercises have the same importance for hand function. Each is therefore attributed a coefficient that determines its position in the hierarchy of importance. It is more important, for example, to be able to close one's hand completely than to fully extend the fingers; thus closing the hand has a coefficient of 3, but opening it has a coefficient of 2.

Calculation method
-Each exercise is graded from 0 to 3.
-Each grade is multiplied by its coefficient to obtain a score.
-The test total is obtained by adding together the 14 scores, and equates to the sum of the scores for the impaired hand.
-Finally, this score is divided by 105 (the maximum score) and then multiplied by 100 to arrive at the mobility percentage for the impaired hand compared to the mobility of a healthy hand.

NB:
If the final result of the test is not a round number: round the figure down if the decimal is 5 or lower, but round the figure up if the decimal is higher than 5. For example, 65.7 becomes 66/10 Interpretation: The patient has 66% mobility in their impaired hand (compared to a healthy hand) 16

TEST 2: PREHENSION STRENGTH
Pretension strength is measured using two different measuring instruments. It is firstly measured on the healthy side, followed by the impaired side. Patients can familiarise themselves with the devices by trying them out with their healthy hand once or twice before starting the test. This test concerns: 1. GRIP STRENGTH using a Jamar® dynamometer (the international standard) set to the second position. This tests the extrinsic and intrinsic muscles. 2. TIGHTENING STRENGTH of the lateral pinch between the surface of the thumb and the radial side of the index finger using a Jamar pinch gauge to test the thumb's extrinsic and intrinsic muscles.

Equipment
 Jamar dynamometer  Jamar pinch gauge

Procedure
Starting position: the patient sits according to the recommendations of the American Society of Hand Therapists, with:  a straight back and feet flat on the floor  the shoulders in an unclenched position  the arms resting loosely  the elbows bent to a 90°angle  the forearms in a neutral position  wrist extension of 0 to 30°with an ulnar deviation of 0 to 15°.
The dynamometers are held by the occupational therapist. For each dynamometer, the score is obtained by finding the average of three successive readings, which are taken alternately on the healthy hand and then the impaired one, etc.

Calculation method
A healthy hand is conventionally considered to have maximum strength. This means that the reading it obtains is the maximum for both dynamometers, namely 10/10. For each dynamometer, the impaired hand is graded by comparison with the healthy hand, and its score is obtained from a crossmultiplication.°F or example, for the Jamar dynamometer: Healthy side = 48 kg; the score for this side is 10/10. Impaired side = 18 kg; the score for this side is as follows:

Weighting
In literature, studies measuring prehension strength attribute 8-12% more prehension strength to the dominant hand as a general rule.
We therefore adjust the result accordingly:°i f the impaired hand is the dominant hand, 10% is deducted from the score obtained°i f the impaired hand is the non-dominant hand, 10% is added to the score obtained

TEST 3: ONE-HANDED GRASP AND OBJECT TRANSFER
This tests the patient's ability to: -pick up 20 objects of varying sizes, weights and shapes placed on a reference surface in a specific order; -transfer them to another surface 50cm above the first, placing them in their corresponding locations.
-The test begins with the healthy hand and continues with the impaired one. The test is timed, so the patient gives more attention to the speed of execution than to the method. As a result, the patient's movements are more natural and spontaneous, and the occupational therapist can easily observe prehension deficits such as exclusion, control dysfunction, compensation, etc.
Equipment 1-One cube with sides measuring 10cm (700g) 2-One cube with sides measuring 7.5cm (300g) 3-One cube with sides measuring 5cm (100g) 4-One cube with sides measuring 2.5cm (10g) 5-One cylinder 12cm high with a diameter of 10cm (700g) 6-One cylinder 11cm high with a diameter of 7.5cm (300g) 7-One cylinder 10cm high with a diameter of 5cm (100g) 8-One marble with a diameter of 25mm 9-One marble with a diameter of 16mm 10-One tennis ball 11-One pin 4cm in length with a diameter of 2mm 12-One electronic lighter 13-One coin with a diameter of 15mm 14-One coin with a diameter of 25mm 15-One coin with a diameter of 30mm 16-One house key 17-Its corresponding lock 18-One iron weighing 2kg 19-One jug with two pouring spouts and 500ml water 20-One ordinary glass -One reference surface is installed as part of a pair of surfaces measuring 30cm x 60cm, with one placed 50cm above the other. They are placed over a height-adjustable table or against a wall with a mechanism to adjust their height.

The table is adjusted so that the upper surface is positioned at shoulder height to the patient.
A mirror affixed to the back of each shelf allows the hand to be observed more easily.

Please note:
Three objects require an action to be performed before they are moved to the top surface: the electronic lighter should be lit using pressure from the thumb - the key should be inserted into the lock, which is then locked and unlocked before the patient removes the key and places it on the top surface part of the 500ml water in the jug is poured into a glass, with the first half of the glass poured in a pronated position and the second half in a supinated position. The water is then poured back into the jug before the patient carries both jug and glass to the top surface.
Before the test begins, the occupational therapist will show the patient how everything is done, explaining that the test is timed and so should be completed as quickly as possible:

"Pick up the objects one by one, starting from the left and moving to the right. Start with the row at the back and repeat for the row in front, again working from left to right." "Place the objects in their corresponding spaces, and remember to light the lighter, to turn the key in the lock and to pour the water from the jug into the glass like this (pronated position) and then like this (supinated position)." "The exercise is timed, so work as fast as you can." "Are you ready? Then please begin!"
Below are examples of each grasp action, showing both the radial and ulnar view for each object, as well as the actions required for some of the objects. The shots were taken in the correct order of the grasp actions, and with the proper adjustment of the two reference surfaces. Thus it is sufficient for the grasp alone or the transfer alone to be wrong for the lowest mark to be awarded for the exercise.
Where patients have permanent impairments caused by the amputation of a finger or arthrodesis, for example, but are able to make optimal use their remaining capacities and carry out the exercises almost normally, unavoidable compensation is permitted.

Please note:
The average time needed for this test is 1 minute or less for a healthy hand. If more than this amount of time is taken, the occupational therapist does not change the score, but can note it as extra information relevant to their patient's rehabilitation.

Calculation method
Each exercise is graded from 0 to 3. The test total is obtained by adding together the 20 different scores: this total equates to the total points for the impaired side. This figure is divided by 60 (the maximum score) and then multiplied by 100 to obtain the one-handed percentage capacity of the patient's impaired hand compared to a healthy hand.
Example: -The total score for the healthy side is equal to the maximum score, namely 60 points.
-Here, the total score for the impaired side equals 46 points. A cross-calculation is then carried out by dividing the total score for the impaired hand by the maximum score, and multiplying this by 100: 46 -------x 100 = 76.6% 60

NB:
When calculating the final result, round the figure down when the decimal is 5 or lower, and round the figure up when the decimal is higher than 5.

TEST 4: TWO-HANDED FUNCTION
This test evaluates the patient's two-handed function by means of 20 tasks drawn from everyday life, and verifies whether hand dominance is upheld. The test is carried out at the patient's pace, without particular instructions or timing of the exercise. However, the test time should not exceed 15 minutes.

NORMAL MOVEMENT*: in cases of amputation or arthrodesis, unavoidable compensation is permitted and a "normal movement" grade may be awarded.
This test also allows any potential transfer of dominance to be observed, especially if the dominant hand is impaired.
For example, a right-handed patient who uses their left hand to open a jar but is able to use their right hand to hold it will be awarded a "3" annotated with the "-" sign. This sign signifies "correct" but with a transfer of dominance.
If the patient's hand dominance is respected, they are graded "3" annotated with the "+" sign.
These observations relating to dominance have no influence whatsoever on the scores awarded; they are simply additional indications that can be used as a guide for any subsequent rehabilitation.

Calculation method
-Each exercise is graded from 0 to 3.
-The total of the 20 scores is obtained by adding them together.
-This result is then divided by 60 (the maximum score) and multiplied by 100 to obtain the patient's two-handed percentage use capacity compared to a person with two healthy hands.

NB:
When calculating the final result, round the number down if the decimal is 5 or lower, and round it up if the decimal is higher than 5.

OVERALL ASSESSMENT CALCULATION METHOD
The overall score is obtained by calculating the sum of the results obtained in all four tests. We can also divide this result by 4, which gives a figure out of 100 points (or a percentage) that is easier to retain: We have 284 points, therefore 284/4 = 71% These results can be illustrated in the form of a bar chart to make them easier and simple to read, both for patients and the various members of the medical and auxiliary staff.

Interpretation: We can state that the functional use capacity of the patient's impaired hand is 71% of that of a healthy hand, or that it is reduced by 29% compared to a healthy hand.
The 400-Point Assessment illustrates patient development in a concrete manner, emphasising progress made or, conversely, underlining a need to continue the work. Beyond a general evaluation, it also highlights particularly significant deficits so that the rehabilitation programme can be adjusted and optimised, or the patient can be referred for surgery.

Test 3
A stopwatch One cube with sides measuring 10cm (700g) One cube with sides measuring 7.5cm (300g) One cube with sides measuring 5cm (100g) One cube with sides measuring 2.5cm (10g) One jam jar with screw lid, filled with particles One bottle of water (50ml) with screw cap and one medicine tube with a push-on lid One bolt with 4mm nut One large box of matches One shirt over a board, with 3 buttons 12mm in diameter, and a further board with 3 laces One needle with a large eye, and some thread