Validation of a pain evaluation scale for patients with severe cerebral palsy

European Journal of Pain (2001) 5: 433±442 doi:10.1053/eujp.2001.0265, available online at http://www.idealibrary.com on

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Validation of a pain evaluation scale for patients with severe cerebral palsy Patrick Collignona and Bernard Giusianob a

CHI, Toulon, France, bAP-HM, Marseilles, France

Polyhandicapped children are extremely limited by severe mental retardation, motor deficiency, perception disability and expression troubles. So pain is very difficult to assess in these patients. We have developed a specific scale for rapid evaluation of pain based on the observation of their behaviour. A first questionnaire listing 22 items was elaborated by physicians and nurses on the basis of their clinical experience. The first part of our study was designed to select the most pertinent items in order to define a final scale for simple and reliable everyday use. The second part of our study was designed to demonstrate the construct validity and the psychometric qualities and to determine the threshold of decision of the 10-item final scale. This tool seems to be sensitive and reliable enough to assess pain in severely cerebrally palsied children and young adults. # 2001 European Federation of Chapters of the International Association for the study of Pain KEYWORDS: pain measurement, polyhandicap, cerebral palsy, mental deficiency, disabled, videotape recording.

INTRODUCTION The term polyhandicap is a French concept motivated by ethical concerns to provide a coherent and humane therapeutic and educational project for `the most needy among the needy' (Salbreux et al., 1979; Salbreux, 1996). It differs slightly from cerebral palsy, which depicts motor problems appearing after a non-evolving cerebral lesion during the first 2 years of life (Ingram, 1964). Polyhandicap is defined as a severe handicap with multiple expression, associating motor deficiencyandseverementalretardation(IQ < 50), causing extreme limitation of autonomy, perception, expression and communication (Zuckman and Spinga, 1985). It could be translated by cerebral palsy with severe mental retardation. Understanding someone's pain implies communication. In polyhandicapped patients there is a panel of handicaps with different degrees. So there must be a great diversity in pain expression. Paper received 29 January 2001 and accepted in revised form 26 June 2001. Correspondence to: Dr Bernard Giusiano, DIM, HoÃpital d'Enfants de la Timone, Rue Saint-Pierre, 13385 Marseille CeÂdex 5, France. Tel: (33) 4 91 38 68 58; Fax: (33) 4 91 38 50 35; E-mail: [email protected]

Severe motor deficiency impairs defensive reactions and antalgesic positions. Tonic troubles, visual and auditory deficiencies and psychotic manifestations could alter the expression of pain. The measurement of pain intensity in these patients is a major concern for the caregivers of specialized institutions. According to physicians, it is difficult to determine whether treatment is necessary or whether the prescribed treatment is effective. These patients are unable to use any self-report scales. In young children, observational rating scales have been set up (McGrath et al., 1985; Gauvain-Piquard et al., 1987). Behavioural scales are very interesting in non-verbal patients (Katz et al., 1980; Jay et al., 1983; LeBaron and Zeltzer, 1984; McGrath et al., 1986; Barrier et al., 1989). Methodological problems in pain assessment with behavioral scales have been well discussed (Serrie et al., 1987; Chwalow, 1993). Most of these scales have been designed for the evaluation of acute pain. However, there are differences in the way children express chronic and acute pain. Only the Gauvain-Piquard scale can be used in chronic pain (Gauvain-Piquard et al., 1987). All these tools are irrelevant for polyhandicapped children because of the great diversity in pain

1090-3801/01/040433 + 10 $35.00/0 & 2001 European Federation of Chapters of the International Association for the Study of Pain

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expression in comparison with other children. In neonates some assessment tools are based in video recording (Grunau et al., 1987; Craig, 1992), but this method is difficult to apply in daily practice and it could raise ethical problems. In cerebrally palsied patients Mette and Abitan (1988) proposed an analogic visual scale used by the nurse. However, this tool is known to be reliable only for self-evaluation. In cognitively impaired patients McGrath developed a checklist of 31 behavioural items extracted from semistructural interviews of primary caregivers (McGrath et al., 1998). The specific behaviours were often different from one child to another but the classes of behaviour were common to almost all children. The authors acknowledge that `there were only 10 individual behavioral items that more than half of the caregivers used. Because of the individual response to pain there may not be a single set of items that can be reliably used to discriminate pain in this population.' We elaborated and validated a scale for rapid evaluation of pain in polyhandicapped patients by observation of their behaviours. Our aim was to define a specific tool available for all handicap patterns and to help physicians in their therapeutic decisions. TABLE 1.

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ELABORATION OF THE FIRST QUESTIONNAIRE This scale was designed to describe different modes of expression of pain in polyhandicapped patients. The severity of deficiencies could be very different from one to another. The use of this instrument had to be easy for nurses in their everyday practice. The first questionnaire was set up by physicians and nurses in HoÃpital San Salvadour on the basis of their clinical experience. This hospital is specializes in curing and caring for severely polyhandicapped patients. The first questionnaire had 22 items focusing on focal aspects of behaviour. These items could be detailed descriptions of minute behaviours or complex behaviours (Table 1). These items could be listed in three groups:  Thefirstgroupof items reflectedanxiety whichis a component of pain expression (items 1, 2, 6, 8, 9, 10, 11). Paradoxical laugh (item 11) could be a painful rictus in the dystonic patient. These signs are not highly specific of pain expression, but they are easily spotted by caregivers.  The second group of items were the direct signs of pain (items 3, 4, 5, 12, 21, 210 ). Items

List of the 22 items in the first questionnaire.

1: Crying and/or yelling during caregiving or potentially painful manoeuvres 2: Painful facial expression during caregiving or potentially painful manoeuvres 3: (Un)coordinated defensive reaction or equivalent on the grazing of an area supposed painful 4: (Un)coordinated defensive reaction or equivalent on the touching of an area supposed painful 5: (Un)coordinated defensive reaction or equivalent on the mobilization of an area supposed painful 6: Ability to respond to potentially painful care giving 7: Resignation or indifference during potentially painful caregiving 8: Spontaneous crying and/or yelling 9: Spontaneous painful facial expression 10: Moaning or silent crying 11: Paradoxical laughing during potentially painful caregiving 12: Spontaneous protection of painful zones 13: Expression of interest in the surroundings 14: Ability of interaction with others 15: Self-mutilating behaviour (psy) 16: Calm autistic behaviour (psy) 17: Trouble falling asleep 18: Nocturnal awakening 19: Increase in tonic troubles 20: Increase in spontaneous movements 21: Active search for an antalgesic position. 210 : Antalgesic posture spotted by caregiver Italicized words correspond to abbreviations used in Fig. 1 and Table 2.

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21 and 210 were mutually exclusive. They described antalgesic positions in severely tetraplegic (item 210 ) or less disabled (item 21) patients. These direct signs are more specific of pain expression. However, they are difficult to spot because of the variety of neuromotor deficiencies in this population.  The third group of items were unusual psychic troubles (items 7, 13, 14) or motor troubles (items 19, 20). In the same group items 15 and 16 described the increase of psychotic troubles. Stereotypical manifestations and self-injury could be a sign of pain expression in mentally retarded psychotic patients (Collignon et al., 1992). Sleep disorders were identified by items 17 and 18. In this population, item scoring cannot be compared with a normal state. So it was based on modification of the usual behaviour of the patient, referred to a personal `basic chart'. This basic chart described the usual state of the patient in different conditions: caregiving, washing, meal, sleep, spontaneous state. So each item includes a definition of a specific behaviour and the description of its increasing severity in five stages: 0: 1: 2: 3: 4:

no modification doubtful modification modification is present major modification extreme modification

To determine whether treatment is necessary or whether prescribed treatment is effective we have to score the maximum intensity of each item during the period of observation.

FIRST PART OF THE STUDY: SELECTION OF ITEMS This first part of our study was designed to select the most pertinent items in order to define a final questionnaire for simple and reliable everyday use. This statistical study was a qualitative study. Patients and methods Our study was performed in a hospital of Assistance Publique-HoÃpitaux de Paris (HoÃpital San

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Salvadour) that specializes in caring for patients with severe mental deficiency. We stated three inclusion criteria:  calender ageÐchildren over 2 years, adolescents or adults;  communicationÐno verbal expression, no communication with signs or symbols;  neuromotor troublesÐsevere spastic, dystonic or mixed deficiencies such as tetraplegia, triplegia, hemiplegia or diplegia. Because of their polyhandicap, these patients could be in pain at any time: peptic oesophagitis, otitis, hip subluxation, severe spasticity. Sometimes they underwent surgery or other painful procedures. However, the number of painful patients by randomly sampling the whole population was unknown. So we defined two groups with the same number of subjects:  Group 1 included patients `likely to feel pain'. These patients were referred to the physician during the study period because of any pathological state: infectious, metabolic, traumatic, epileptic or other stress.  Group 2 included patients with no particular reason to suffer. It was a formal random sample in the total population minus group 1. Each patient of group 2 was included every time another one was included in group 1. For each included patient the physician made a summary of the medical record. He scored motor autonomy in three stages: 0: no motor autonomy 1: control of cephalic segment 2: control of at least one upper limb For each included patient the primary caregiver filled in the basic chart. Then he/she scored each item of the questionnaire from direct observation during the last 8 h of caring. This evaluation was performed three times during 24 h. Five experts (two physicians and three nurses) were trained to use the scale and they helped the caregivers to score the items. For each patient one of these experts gave a personal opinion in three levels after clinical examination: 0: does not suffer 1: seems to suffer 2: certainly suffers European Journal of Pain (2001), 5

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In this population, data variability might have been linked more with the severity of the handicap than with the presence or absence of pain. So we used multiple correspondence analysis (MCA) (Saporta, 1990) to define the relative importance of each item and to clear these confounding factors. For this MCA the scores were conflated into three levels: 0: usual manifestation 1: modification of behaviour NP: non-pertinent item An item is non-pertinent for a selected patient when it is impossible to answer the question because of the specificity of the handicap in this case. The results of this descriptive study were controlled by the 2 test. The sensitivity and the specificity of the remaining items were tested against the expert's opinion on pain. Results During the 6 months of this first study we included 62 patients (31 in group 1 and 31 in group 2). The mean age was 16.5 years (range: 2±33 years). There were 38 males and 24 females. The most frequent

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neuromotor troubles were tetraplegia (43/62) and spasticity (20/62). In 29 cases no voluntary motricity of the four limbs was possible (degree 0 or 1). In 42 cases psychotic troubles were observed. The initial 22-item questionnaire was reduced to 10 items. Items 6, 7, 11, 17 and 18 were difficult or impossible to score according to the experts. Non-pertinence was often scored for items 12, 21 and 210 , because these signs depend on the patient's autonomy. The weight of each item was defined by MCA on qualitative variables. Results showed a strong cohesion between some items. So these items were conflated into one new definition: crying (items 1 and 8), painful facial expression (items 2 and 9) and defensive reaction (items 3, 4 and 5). MCA showed a first factor (axis 1) related to the signs of anxiety. If we include on the graph the variable `expert's opinion' scored at three levels (0, 1, 2) we can see that axis 1 is related to the existence of pain. The same comparison shows that psychotic signs (items 15 and 16) are not relevant in pain diagnosis. The second factor (axis 2) is related to motor autonomy scored in the medical record (0, 1, 2). Motor autonomy is related to direct signs (Fig. 1). Pertinence, rather than positivity of direct signs, is linked with axis 2. These signs are also related to axis 1 with

FIG. 1. MCA of items of the first questionnaire. Next to the scale items scored on three degrees (0 ˆ usual manifestations, 1 ˆ modification, NP ˆ non-pertinent item) is the examiners' opinion (`suffers': 0 ˆ does not seem to suffer, 1 ˆ seems to suffer, 2 ˆ certainly suffers) and the degree of motor autonomy (`motricity': 0 ˆ no motor control, 1 ˆ control of the cephalic segment, 2 ˆ control of at least one upper limb). European Journal of Pain (2001), 5

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the same coherence but to a lesser degree than signs of anxiety. These two factors can explain a little more than 50% of variance (axis 1, 34%; axis 2, 18%). On the MCA graph of individuals, the patients are located in four groups: severely dependent and more autonomous patients are delineated by the first axis, and the second axis delineates suffering patients and pain-free patients according to the expert's opinion (Fig. 2). In the first part of the study the experts were certainly influenced by the scoring of the questionnaire. So the experts' opinion correlates with axis 1, and the specificity of each item, i.e. the ability to detect only suffering patients, seems to be high. In another way, sensitivity, i.e. the ability

to detect all suffering patients, is different for each item (Table 2). The items with the best negative predictive value, i.e. probability of no pain when the sign is absent, are crying (items 1 and 8), facial (items 2 and 9), protection (item 12) and defensive (items 3, 4 and 5). Signs of anxiety, direct signs of pain and increased tonic trouble (item 19) have a good positive predictive value, i.e. pain is present when the sign is positive. So 10 items where selected for the final questionnaire (Table 3). The criteria of selection were sensitivity, specificity, pertinence with different degrees of motor autonomy, easiness to score. Different groups of signs were associated (anxiety, direct, psychic, motor) in order to assess every possible expression of pain in the different polyhandicapped patients.

SECOND PART OF THE STUDY: VALIDATION OF THE SCALE

FIG. 2. Positioning the individuals around the two axes of MCA.

TABLE 2. Number 1,8 7 10 11 12 18 19 21 17 20 2,9 14 13 6 210 3,4,5 16 15

The first part of the study defined a 10-item final questionnaire with a good content validity. Filling in this scale takes only 10±15 min, regardless of the cause of pain and the patient's motor autonomy. The second part of the study was designed to demonstrate the construct validity and psychometric qualities and to determine the threshold of decision. This qualitative study

Specificity and sensitivity of each item of first questionnaire, in decreasing order. Item

Specificity

Number

Item

Sensitivity

Crying Resignation Moaning Laughing Protection Awakening Tonic Position Asleep Movements Facial Others Surroundings Care Posture Defensive Psy Psy

1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 0.97 0.97 0.97 0.97 0.97 0.95 0.94 0.83 0.81 0.79

1,8 2,9 12 3,4,5 11 6 10 19 13 15 210 14 21 16 20 7 18 17

Crying Facial Protection Defensive Laughing Care Moaning Tonic Surroundings Psy Posture Others Position Psy Movements Resignation Awakening Asleep

0.93 0.93 0.89 0.83 0.67 0.64 0.63 0.44 0.35 0.33 0.33 0.32 0.30 0.25 0.22 0.20 0.19 0.11

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Final 10-item questionnaire.

Item 1: Crying (cries with or without tears) 0: manifests as usual 1: seems to manifest more than usual 2: cries with manipulation or potentially painful manoeuvres 3: spontaneous and unusual crying 4: same signs as 1, 2, or 3 accompanied by neurovegetative manifestations (tachycardia, bradycardia, sweating, rash, or pallor) Item 2: Coordinated defensive reaction or equivalent on examination of an area supposed painful (grazing, touching, or mobilization induces a coordinated bodily reaction or equivalent that we can interpret as a defensive reaction) 0: habitual reaction 1: seems to react in an unusual way 2: unusual movement 3: same signs 1 or 2 with smirking or moaning 4: same signs 1 or 2 with jerking, shouting, and crying Item 3: Painful expression (the face shows pain; a paradoxical laugh can correspond to a painful rictus) 0: manifests as usual 1: anxious and unusual appearance 2: painful expression with manipulation or potentially painful manoeuvres 3: spontaneous painful expression 4: same signs as 1, 2, or 3 accompanied by neurovegetative manifestations (tachycardia, bradycardia, sweating, rash, or pallor) Item 4: Protection of painful areas (protects the area supposed painful with his/her hand in order to avoid contact) 0: habitual reaction 1: seems to fear touching of particular area 2: protects a particular area of his/her body 3: same signs as 1, 2, or 3 with smirking or moaning 4: same signs as 1, 2, or 3 accompanied by jerking, shouting, and crying Item 5: Moaning or inaudible cries (moans with manipulation or spontaneously, in an irregular or continuous way) 0: manifests as usual 1: seems to moan more than usual 2: moans in an unusual way 3: moaning with painful expression 4: moaning with shouting or crying Item 6: Spontaneous interest for the surroundings 0: manifests as usual 1: seems less turned outwardly than usual 2: attention deficit, must be solicited 3: turned inwardly, does not react on being solicited 4: unusual prostration Item 7: Aggravation of tonic troubles (increase in stiffness, tremulations, hypertonic spasms) 0: manifests as usual 1: seems stiffer than usual 2: aggravation of stiffness during manipulation or potentially painful manoeuvres 3: same signs as 1 or 2 with painful expression 4: same signs as 1, 2, or 3 with shouting and crying Item 8: Ability to communicate with the nurse (by searching, expressions, or babbles, spontaneously or when being solicited) 0: manifests as usual 1: seems less open to communication 2: unusual difficulties to make contact 3: unusual contact refusal 4: unusual and total indifference Item 9: Increase in spontaneous movement (voluntary motricity or not, coordinate or not, choreoathetotic movements of limbs or head) 0: manifests as usual 1: possible increase

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TABLE 3. Continued 2: unusual jerking 3: same signs as 1 or 2 with painful expression 4: same signs as 1, 2, or 3 with shouting and crying Item 10: Spontaneous antalgesic position (search for an unusual position that calms) or placed in antalgesic position by nurse 0: usual comfortable position 1: seems less comfortable in this position 2: certain positions are no longer tolerated 3: calmed by an unusual position 4: no position is calming When an item appears to be irrelevant, it is scored zero.

aimed to validate the scale and to define the practical modalities of use. Patients and methods It was a multicentric study performed in two hospitals of Assistance Publique-HoÃpitaux de Paris (HoÃpital San Salvadour and HoÃpital de la Roche Guyon) that specialized in caring patients with severe mental deficiency. Inclusion criteria were the same as for the first study. Included patients were divided in two groups in the same way:  group 3Ðincluded patients `likely to feel pain';  group 4Ðincluded patients with no particular reason to suffer by a formal random sample in the total population minus group 3. There is no `gold standard' for evaluation of pain. Studies have been set up comparing scales with experts' opinion based on video recording. These data used the methodology of social validation described by Kazdin (1977). Examples are CHEOPS (McGrath et al., 1985) and the DEGR scale (Gauvain-Piquard et al., 1987). Our protocol involved five steps. 1. A new basic chart with 10 questions related to each item of the scale was filled in for every included patient by his/her usual caregiver (Table 4). 2. The 10-item scale was scored for every included patient by the nurse and the caregiver staff from direct observation during the last 8 h. The total score was the sum of the 10 item scores. If an item was non-pertinent, i.e. irrelevant for the patient, it was scored at level 0.

3. At the same time every included patient was video recorded in different situations: washing, nurse care or physical therapy. 4. Three experts independently gave their opinion on video recordings compared with the basic charts. These experts were two physicians from HoÃpital San Salvadour and one physician from HoÃpital de La Roche Guyon. Experts' opinion was scored in four degrees, leading to a binary final choice: 0: does not seem to suffer (no treatment) 1: pain is caused only by some manipulations (no treatment) 2: seems to suffer (analgesic treatment) 3: pain is certain (analgesic treatment) 5. A scale decision was evaluated by the total score compared with a threshold defined by the ROC curve. This curve shows the best compromise between sensitivity and specificity including all the data. The scale decision was compared with the experts' decision by calculating the  coefficient (Cohen, 1960). The internal consistency of the scale was assessed by the  coefficient (Cronbach, 1951).

Results Fifty patients were included in the second part of the study. Mean age was 20 years (range: 6±33 years). There was no significant difference in age, psychotic troubles or motor autonomy between groups 3 and 4. The 25 patients of group 3 had medications during the examination period. Eighteen of them had analgesic treatment. European Journal of Pain (2001), 5

440 TABLE 4.

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Basic chart describing usual behaviour.

1: Does the subject usually cry? If so, under what circumstances? Does he/she sometimes cry? If so, for what reasons? 2: Are there usual motor reactions when the subject is manipulated? 3: Does the subject usually smile? If so, is his/her face expressive? 4: Is he/she able to protect his/her face? If so, does he/she tend to do so when touched? 5: Does he/she moan? If so, under what circumstances? 6: Is he/she interested in his/her surroundings? If so, is the interest spontaneous or secondary to stimulation? 7: Is stiffness a problem in everyday life? If so, under what circumstances? (Give examples.) 8: Does he/she communicate with others? If so, does he/she search for contact or must it be elicited? 9: Does he/she present spontaneous motor behaviour? If so, is it voluntary movement, uncoordinated movement, a choreoathetoid syndrome, or reflex movement? If so, is movement occasional or rather permanent agitation? 10: What is his/her usual comfort position? Does he/she tolerate the seated position?

Internal scale coherence Usage frequency of every degree (from 0 to 4) of the score for each item showed that all items were useful. Cronbach's  coefficient was 0.93, showing a good internal scale coherence. Between-expert consensus Between-expert consensus was evaluated by Cohen's  coefficient. Agreement is good when  is greater than 0.60 and poor if less than 0.30. Agreement was between these values on detailed experts' opinion (levels 0, 1, 2, 3) showing the difficulty of pain evaluation. The three experts did not assess pain in the same way. However, in most cases they agreed in their binary decision to treat or not to treat. So agreement is improved if we compare this binary decision (Table 5). If the average of experts' scores (levels 0, 1, 2, 3) was more than 1, we considered that analgesic treatment is necessary. With this criterion, the experts chose to treat (or to increase dosage) in 17 of 50 cases (Table 6). Determination of the threshold of decision The ROC curve defines the best compromise between sensitivity and specificity referring to the treatment/no treatment decision of the expert panel. The threshold is the closest point to the upper left corner of the graph (Fig. 3). In our case two points are located in the upper left: scores 2 and 6. On point 2 sensitivity is high and specificity is medium. Between 3 and 6 specificity increases with the same level of sensitivity. So we can use European Journal of Pain (2001), 5

TABLE 5. Cohen's  coefficients for between-expert consensus.

On evaluation scores Expert X Expert Y On binary decisions Expert X Expert Y

Expert Y

Expert Z

0.52

0.49 0.39

0.64

0.75 0.56

TABLE 6. Decision of the experts and prior existence of treatment. Therapeutic state at protocol inclusion Already with antalgesic No antalgesic

Expert's decision Treat

Not treat

11 6 17

7 26 33

18 32

the scale in that way: if the score is greater than or equal to 2, the patient may suffer and needs particular attention; if the score is greater than or equal to 6 pain is highly presumed and analgesic treatment is required. Consensus between the scale and the expert panel The  coefficient shows a good agreement between the scale and the experts (Table 7). Expert X seems to focus on the decision to treat (more specific), expert Y seems to worry with

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TABLE 8. scale.

Global sensitivity and specificity of the

Scale (threshold ˆ 2) Scale (threshold ˆ 6)

Sensitivity

Specificity

0.88 0.76

0.73 0.88

TABLE 9. Scale sensitivity according to scoring modalities. Scoring modality 5 degrees FIG. 3. ROC curve to choose the threshold value of scale interpretation. TABLE 7. Consensus between the scale and the expert panel.

Scale (threshold ˆ 2) Scale (threshold ˆ 6)

Expert X

Expert Y

Expert Z

0.64 0.74

0.68 0.57

0.47 0.48

signs of anxiety (more sensitive) and expert Z's attitude is more difficult to evaluate. Sensitivity and specificity of the scale Relative to global results (Table 8), the scale sensitivity would be lower if the scoring had used two instead five levels (Table 9). The scale specificity would be better with the most pertinent items for each patient according to his/her motor autonomy: 0.79 with threshold 2, 0.91 with threshold 6. The patterns of most pertinent items are showed by the results of MCA:  items 1, 3, 5, 6, 7 and 10 if no motor control;  items 1, 2, 4, 5, 6, 7 and 8 if control of the cephalic segment is present;  items 1, 2, 4, 5, 8, 9 and 10 if there is control of at least one upper limb. So all the 10 items are useful to assess pain regardless of the severity of motor deficit.

DISCUSSION Our first questionnaire was defined by `implicit consensus' with a staff of physicians and nurses.

Scale (threshold ˆ 2) Scale (threshold ˆ 6)

2 degrees

0/1/2/3/4

0/1234

01/234

0.88 0.76

0.82 0.53

0.76 0.41

McGrath transcribed interviews of primary caregivers to define a checklist of 31 items of pain expression in non-verbal, cognitively impaired individuals (McGrath et al., 1998). Twenty-one of the 22 items of our first questionnaire can be matched against the items of this checklist. Our protocol was based on statistical tools. The results of our first study were confirmed by another study using an original mathematical method: the neural network. This other study was published in a previous paper (Giusiano et al., 1995). In the second part of our study, total independence between patients and experts was impossible. Expert X and Z practiced in HoÃpitat San Salvadour where two-thirds of the included patients were cured. Expert Y practiced in HoÃpital de La Roche Guyon. They did not know the patients' group (3 or 4) and they did not have the patients' scale. However, they were probably influenced during video screening when they recognized their own patients. However, results are consistent, despite different sensitivity from one to another. The experts do not always agree but the assessment of pain is a question of subjectivity (Holm, 1989). Despite the difficulties of this study, the validity and reliability are really good. This study was designed to help the physicians to determine whether treatment is necessary or not. It was an essential step for us as it questioned routine prescription habits. Since this study morphine European Journal of Pain (2001), 5

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derivatives have been more currently prescribed in these two hospitals (Collignon et al., 1997). Other studies should be carried on in surgery units and intensive care units that care for polyhandicapped patients. Scoring would be done by caregivers who do not know the patient and who have less experience with this particular pathology. So the expert panel could be independent.

ACKNOWLEDGEMENTS We wish to thank the staff of HoÃpital San Salvadour and HoÃpital de La Roche-Guyon. Thanks are also due to A.M. Boutin, J.C. Combe, E. Porsmoguer, M.T. Jimeno, F. Vintilla, J.L. Aubert and P. Auquier for their kind assistance. The third stage of this work was supported by an INSERM grant (CNEP, 92 CN 02).

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