88ournal ofNeurology, Neurosurgery, and Psychiatry 1993;56:868-873

Assessing tremor severnty

P G Bain, L J Findley, P Atchison, M Behari, M Vidailhet, M Gresty, J C Rothwell,P D Thompson, C D Marsden

AbstractA clinical rating scale which measuredthe severity of tremor in 20 patients (12with essential tremor and 8 with "dys-tonic" tremor) was assessed at specificanatomical sites for both inter and intra-rater reliability using four raters. Thescores obtained with the scale were com-pared with the results of upper limbaccelerometry, an activity of daily livingself-questionnaire and estimates of thetremor induced impairment in writingand drawing specimens. The resultsshow that, for the purposes of routineassessment and therapeutic trials, a clin-ical rating scale can produce reliableresults which are a more valid index oftremor induced disability than standardpostural accelerometry.

(T Neurol Neurosurg Psychiatry 1993;56:868-873)

MRC HumanMovement andBalance Unit, TheInstitute ofNeurology,Queen Square,London WCIN 3BG,UKP G BainL J FindleyP AtchisonM BehariM VidailhetM GrestyJ C RothwellP D ThompsonC D MarsdenCorrespondence to: Dr BainReceived 31 July 1992and in revised form4 November 1992Accepted 6 November 1992

During the last two decades there have beenan increasing number of clinical trials evalu-ating the effect of drugs on tremor severity. Inpractice these trials have relied heavily on

accelerometry as the objective method ofmeasurement, and clinical rating systems andpatient self-assessments as the subjectivemethods. The purpose of this study was todetermine whether or not a clinical ratingscale could be used reliably to evaluate theseverity of tremor in patients with essentialtremor and postural limb tremor associatedwith dystonia. Furthermore, the scores

obtained by using the scale were comparedwith the results of upper limb accelerometry,two assessments of dominant hand function(handwriting and drawing a spiral) and a

patient activity of daily living self-question-naire.The rating scale used is illustrated in

Appendix 1 and was chosen after experiment-ing with various alternatives which estab-lished that clinicians found the combinationof a "discrete step" verbal scale and a numeri-cal (0-10) analogue scale helpful for scoring.It is slightly unusual in having more stepsthan most tremor rating scales,'l but thistends to increase its precision and reliability.9As the number of scale steps increases, so

does the difficulty of consistent judgement.However, by also decreasing the significanceof a "unit" error, true score variance is alteredadvantageously for reliability.'0

Tlhe scale relies on the examiners havingsome experience of movement disorders and

utilises a cognitive process whereby anobserver ascribes a number to a phenomenonto indicate its degree of membership to a set.The technical term for this process is "fuzzylogic"." The scale differed from previoustremor rating scales not only in providing abroader gradation system,'l but also by relat-ing tremor magnitudes to different bodyparts,'4 including the head,25 and in additionwe avoided inclusion of measurements of dis-ability and handicap within the scale.'45 Toour knowledge the inter and intra-rater relia-bility of previous tremor rating scales andtheir validity as a measure of tremor induceddisability have never been assessed formally.Similarly, the validity of standard accelerome-try as a measure of tremor induced disabilityhas not been documented.The rating scale which we developed

(Appendix 1) was subjected to validationagainst a disability self-questionnaire,accelerometry and scores for the degree ofimpairment seen in spirography and hand-writing specimens, techniques commonlyemployed in clinical trials. The inter andintra-rater reliability of the rating scale and ofthe spirography and handwriting scores werethen measured.

PatientsTwenty patients with postural tremor of theirupper limbs were recruited from the clinic ofthe National Hospital for Neurology andNeurosurgery, Queen Square. Twelvepatients were diagnosed as having pure essen-tial tremor and eight had postural limbtremor in association with torticollis (dysto-nia). Ten of the patients had tremor of thelower limbs, 10 had head tremor (of whom 8had torticollis) and in 6 a vocal tremor wasdetected. Ten were male and 10 female.Their average age was 64-5 years (range26-82 years) and their mean duration oftremor 14'2 years (range 2-49 years).Nineteen were right handed and one, whowrote with the right hand, was ambidexter-ous. None of the patients had other signifi-cant illnesses and all the assessments werecarried out without interrupting their medica-tion. The patients were not aware of theirscores.

DefinitionsThe various components of tremor weredefined by an Ad Hoc committee of theTremor Research Group [TRIG] in the fol-lowing way.'2

868 on S

eptember 7, 2020 by guest. P

rotected by copyright.http://jnnp.bm

j.com/

J Neurol N

eurosurg Psychiatry: first published as 10.1136/jnnp.56.8.868 on 1 A

ugust 1993. Dow

nloaded from

Assessing tremor severity

1) Rest Tremor: tremor occurring when themuscles are not voluntarily activated and therelevant body part is completely supportedagainst gravity.2) Postural Tremor: tremor present whilevoluntarily maintaining a position againstgravity.3) Kinetic Tremor: tremor during any formof movement.4) Intention Tremor: the pronounced exac-erbation of kinetic tremor towards the end ofa goal directed movement.

These definitions were familiar to theraters and were used in this study.

MethodsA) Validation of the ScaleEach patient was sent an "activities of dailyliving" (ADL) self-questionnaire to documentthe extent of their tremor induced disability.The questionnaire consisted of an inventoryof 25 different activities of daily living and isbased on that used in previous studies(Appendix 2).'324 Each patient was asked tocircle the number (next to each item) whichdescribed most accurately how easy or diffi-cult it was for them to perform the relevantactivity. The sum of the scores for each itemwere then converted into percentages, withzero implying no disability and the higher thepercentage the more disabled the patient.Two weeks later the patients attended a

grading clinic during which their tremorswere independently rated by four doctorsusing our clinical rating scale. The severity ofeach patient's head, vocal, right upper limb,left upper limb, right lower limb and leftlower limb tremors were scored separately(from 0-10) by each rater. For each anatomi-cal site the components of tremor (rest, pos-tural, kinetic and intention) were scoredindividually (see Appendix 1). During thegrading clinic the patients had their tremorsvideotaped and their upper limb posturaltremors measured by accelerometry. Theywere also asked to draw a spiral and give aspecimen of their handwriting to one of theraters. To reduce any systematic bias theorder of all these assessments was ran-domised. The spirals were drawn and hand-writing done with the pen held normally andthe wrist resting on the table and the patientseated.

AccelerometryAccelerometry was performed on the pro-nated outstretched upper limbs, whilst thepatients were sitting. Miniature piezo-resistivelinear accelerometers (with vertical as thedimension of recording) were attached to thedorsal aspect of each hand in the secondinterspace, 1 cm proximal to the metacar-pophalangeal joints. The devices weighed 6 gand had flat frequency responses from steadystate acceleration to 300 Hz with a sensitivityof 50 m V/g (g = 9-81 m/s2). The posturaltremor in each hand was then recorded forone minute. The accelerometer signals wereamplified and analysed on-line, using a

Hewlett Packard 5420 A signal analyser,'5 toproduce an average of ten overlapping spectrawhich displayed the root mean square (rms)magnitude of the frequency components as afunction of frequency. Measurements weretaken for each hand of the frequency (Hz) ofthe dominant peak and of its magnitudescaled in rms acceleration, units of g (whichwere converted to m/s2).

Clinical GradingThe clinical grading of the various compo-nents of tremor was performed in the follow-ing way: the rest component of head tremorwas assessed with the patients lying flat on acouch, with the head supported by pillows,and the postural component whilst thepatients were sitting without head supportlooking straight ahead. The postural compo-nent of leg tremor was scored whilst eachpatient was sitting with the relevant legextended and the rest component when thefoot was placed on the floor. The upper limbswere, once again, assessed with the patientssitting. The rest component of tremor wasscored whilst the arms were relaxed andtotally supported in the patient's lap and thepostural component whilst they were out-stretched, with the hands pronated and fin-gers spread (as for accelerometry). Thekinetic component was measured during thetransit phase of the finger-nose test and theintention component as the subject's indexfinger approached a target (the tip of a patellahammer) placed at the limit of reach. Vocaltremor was scored by asking each patient tosay their own name, address and birthday andto hold a note by singing "aah".

B) The Reliability of the ScaleThe inter and intra-rater reliability of thescale was assessed using videotape of thepatients seen in the assessment clinic and thesame raters. Two video assessment sessionswere carried out; the first (A) one month andthe second (B) two months after the initialassessment in clinic. Once again the specifictremors were scored according to site andwere subdivided into rest, postural, kineticand intention components. However, duringthe video assessments the postural compo-nent of upper limb tremor was rated whilstthe hands were held pronated in front of thepatient's nose (but not quite touching) withthe shoulders abducted to the horizontal.No comparisons have been made between

the clinic and video assessments because sev-eral difficulties have become apparent in esti-mating tremor severity from videotapes.Notably, most standard VHS video-recorderspresent the viewer with complete images at arate of 25 Hz (alternate lines are changed at50 Hz). Consequently, for a tremor with afrequency of 5 Hz, there are 5 picture framesper tremor cycle; whereas only 2-5 frames pertremor cycle occur if the frequency is 10 Hz.This produces a differential effect wherebymore information is lost the faster the tremorfrequency and thus there is a greaterreduction in the apparent amplitudes of high

869 on S

eptember 7, 2020 by guest. P

rotected by copyright.http://jnnp.bm

j.com/

J Neurol N

eurosurg Psychiatry: first published as 10.1136/jnnp.56.8.868 on 1 A

ugust 1993. Dow

nloaded from

Bain, Findley, Atchison, Behari, Vidailhet, Gresty, Rothwell, Thompson, Marsden

compared with low frequency tremors. Theapparent amplitude of a tremor seen on avideoscreen also depends on the distance ofthe observers from the screen and the size ofthe images; which is influenced by theamount ofzoom used by the cameraman.

Immediately after each video session thespirography specimens were ascribed scoresindependently by each rater. The spirals hadbeen photocopied to provide four anonymoussets of twenty and within each set the order ofthe spirals had been randomised. Each raterranked the twenty spirals from best (normal)to worst (most tremulous) and then ascribedeach spiral a score from 0 (normal) to a possi-ble maximum of 10 (extremely tremulous);although in practice 0-8 was the range ofscores given. An identical procedure was usedfor rating the handwriting specimens whichwere again scored after each video session (Aand B). The order in which the spirals andhandwriting were assessed by each rater wasalso randomised.The inter and intra-rater reliabilities of the

assessments of each tremor component (rest,postural, kinetic and intention) at eachanatomical site and the scores for spirographyand handwriting were calculated usingCohen's Kappa coefficient.1618 This providesa measure of the degree of inter-observeragreement for pairs of observers assigningindividual observations subjectively to one ofa range of categories. Similarly, the intra-observer reliability (comparison of observa-tions made by a single observer at twodifferent times) can be measured. Kappascores are conventionally interpreted asfollows'7:Kappa Strength ofCoefficient Agreement< 0 Poor

0- 0-20 Slight0-21-0A40 Fair0 41-0 60 Moderate061-0-80 Substantial0 81-1-00 Almost perfectThe validity of the scale was assessed by

measuring the correlation between the meanscores for the postural components of head(pHT), right upper limb (pRUL), left upperlimb (pLUL), right lower limb (pRLL) andleft lower limb (pLLL) tremors of thepatients and their activity of daily living(ADL) scores, spirography and handwritingimpairments and upper limb acceleration and

frequency. In our correlation (regression)analysis we used the mean of the raters'scores as recorded in the clinic and the meanof their first assessments of each patientsspirography and handwriting impairments.

ResultsReliabilityThe inter and intra-rater reliabilities for thepostural component of head and limb tremor,expressed as Cohen's Kappa coefficients, areillustrated in table 1. The rating scale provedto have good inter and intra-rater test-retestreliability for assessing the postural compo-nents of head and upper limb tremor, whichare the principal sites affected by essentialand "dystonic" tremor, and fair-moderate forlower limb postural tremor. However, theKappa coefficients for the inter-rater reliabili-ty of vocal tremor assessments were poor-fair(Kappa values of - 0-008-0-32). This wasbecause of disagreement between the raters asto which of the patients had vocal tremor.The inter-rater reliability of the assess-

ments of spirography and handwritingimpairment were 0 56-0 90 (moderate-almost perfect) and 0-31-0-83 (fair-almostperfect) respectively and the intra-rater relia-bility was 0-58-0 91 (moderate-almostperfect) for handwriting and 0-36-0-88 (fair-almost perfect) for spirography. The ratershad great difficulty in applying the termskinetic and intention tremor to real life obser-vations, in spite of having previously agreedon these definitions. For instance the Kappavalues for the inter-rater reliability of rightupper limb kinetic and intention tremor com-ponents were 0*02-0X65 (slight - substantial)and - 0 03-0-54 (poor-moderate) respective-ly. This reflects the practical difficulty ofdefining the boundaries of an intentiontremor when kinetic and postural compo-nents are also present. Consequently, duringthe second video assessment "intention"tremor was not scored and, by confiningattention to recording the severity of thekinetic tremor seen midway through a move-ment, greater inter-rater agreement wasobtained; for example 0-44-0-66 (moderate-substantial) for the right upper limb.Kappa analysis was not performed on the

rest components of tremor as these wereobserved too infrequently to produce mean-ingful results. Furthermore, it is the action

Table 1 Reliability of the rating scale for assessing postural tremor

A Inter-rater reliabilitySite ofTremor Kappa Value Strength ofAgreementRight upper limb 0-60-0-81 moderate-almost perfectLeft upper limb 0 55-0 77 moderate-substantialRight lower limb 0-28-0-49 fair-moderateLeft lower limb 0 39-0 59 fair-moderateHead 0-58-0-84 moderate-almost perfect

(P of Kappa less than 0-01)B Intra-rater reliabilitySite ofTremor Kappa Value Strength ofAgreementRight upper limb 0-72-0-85 substantial-almost perfectLeft upper limb 0-62-0-76 substantialRight lower limb 0 40-054 fair-moderateLeft lower limb 0-23-0-56 fair-moderateHead 0-71-0-78 substantial

(P of Kappa less than 0 01)

870 on S

eptember 7, 2020 by guest. P

rotected by copyright.http://jnnp.bm

j.com/

J Neurol N

eurosurg Psychiatry: first published as 10.1136/jnnp.56.8.868 on 1 A

ugust 1993. Dow

nloaded from

Assessing tremor severity

Table 2 Correlation coefficients (r-values) for therelationships between spirography and handwritingimpairment, right upper limb acceleration andfrequency,the mean of the raters' scores for the postural component ofhead tremor (pHT), and right upper (pRUL) and lower(pRLL) limb tremor and the disability self-questionnaire(ADL). (* implies signficance at the 1% level.)

Spirography Writing pRULADL impairment impairment score

Spirographyimpairment 0-659*

Writingimpairment 0-686* 0-917*

pRUL score 0-628* 0-804* 0-762*pRUL

acceleration 0-039 0-406 0-343 0-655*pRUTL frequency 0-248 0-196 0-159 0-206pHT score 0-398 0 039pRLL score 0-055

rather than the rest component of tremorwhich would be expected to contribute to thedifficulties experienced by patients in theirdaily living activities.

ValidityCorrelation coefficients (r-values) for some ofthe relationships between spirography andhandwriting impairment, right upper limbaccelerometry, the raters' scores for the pos-tural component of head and right upper andlower limb tremor and the disability self-questionnaire are shown in table 2. Theraters' scores for the right upper limb posturaltremor component in each patient correlatedwell with the results obtained from the dis-ability self-questionnaire and acceleration inthe same arm, as well as handwriting andspirography. In contrast the frequency andacceleration values from right upper limbaccelerometry were poorly correlated withdisability, spirography and handwriting(table 2).The correlation coefficients (r-values) for

the relationships between the frequencies,acceleration and raters' scores for the posturalcomponent of tremor in the right comparedwith the left upper limbs were 0-22, 0.51*and 0-72* respectively (*significant at 1%level); indicating significant symmetries in theclinical severities and RMS acceleration ofthe tremors in the upper limbs, but asym-metry of the peak frequencies. Similarly, theseverity of postural tremor in the patients' leftlower limbs was highly correlated with that inthe right (0.976*), again suggesting a highdegree of symmetry as judged by the raters.The grand averages of the patients' scores

Table 3 The grand averages of the patients' scores. Thevalues shown are the averages of all those obtainedfromthe patients during the grading clinic, from the firstspirography/handwriting assessment andfrom the selfquestionnaire (ADL%).

Mean Range

ADL% 17 0-49Writing impairment (0-10) 3-0 0-8Spiral inpairment (0-10) 3-6 0-8pRUL acceleration (m/s2) 0-537 0-04-2-04pLUL acceleration (M/S2) 0-385 0-03-1-35pRUL frequency (Hz) 5-45 2-4-8-8pLULfrequency (Hz) 5 12 2-4-6-8pRUL (0-10) 2-8 0-8pLUL (0-10) 2-4 0-7pRLL (0-10) 0-4 0-2pLLL (0-10) 0-4 0-2pHT (0-10) 1.1 0-5

are shown in table 3, which gives an impres-sion of the "state" of our "average" patientand of the range of scores observed.The percentage of patients reporting diffi-

culty with each item in the activities of dailyliving self questionnaire are shown in appen-dix 2.

DiscussionA quick, reliable and valid method of assess-ing postural tremor is necessary if changes intremor behaviour are to be documented rou-tinely and the results of clinical trialsappraised. A clinical rating scale has advan-tages over accelerometry because no appara-tus is required, it is cheaper, and morepractical and the results are more comprehen-sible and meaningful to most physicians (andpatients). Furthermore, accelerometry is notwidely available in clinical practice.The design of this study was deliberately

meant to mimic a "typical" multicentre cross-over therapeutic trial, as this was one of theintended uses of the scale. The four raterswere therefore specifically chosen because oftheir varied countries of training and practice(UK, USA, France and India). Furthermore,the timings of the initial assessment clinic andthe two video sessions (A and B) werearranged to simulate the schedule of a cross-over trial (in which twenty patients wereassessed (grading clinic) and then enteredinto a trial, reassessed after one month (videosession A), crossed over and rerated onemonth later (video session B)). None of theraters had been given any previous experienceof the rating scale before the assessment clin-ic; apart from a short briefing on how to useit.A sample size of twenty patients and four

raters were used, because these were consid-ered to be the largest numbers manageable ina single clinic.The results show that a clinical grading

scale can provide a reliable method of assess-ing postural tremor severity, particularly ofthe upper limbs and head; which are the prin-ciple sites affected by essential tremor and the

ACCELERATION V RIGHT HAND SCORE

2.50

0

Ez0

w-1w00

2.00

1.50

1.00

0.50 O1 2 S 4 5 6 78~~~~~I

RIGHT HAND SCORE (0-10)

Figure The graph shows the relationship betweenacceleration (mis2) and tremor score (0-10) of thepostural component of right upper limb tremor.(Correlation coefficient, 0-655*).(*significant atp < 001).

871

A

0.00

on Septem

ber 7, 2020 by guest. Protected by copyright.

http://jnnp.bmj.com

/J N

eurol Neurosurg P

sychiatry: first published as 10.1136/jnnp.56.8.868 on 1 August 1993. D

ownloaded from

Bain, Findley, Atchison, Behari, Vidailhet, Gresty, Rothwell, Thompson, Marsden

tremor associated with dystonia. Theseresults correlated well with the patients owndisability ratings (table 2). In contrastaccelerometry, which has become a standardtechnique for assessing tremor in clinical tri-als and provides a quantitative measurementof upper limb tremor (fig), is not a validmethod of assessing the functional signifi-cance of postural tremor upon patients (table2). It does, however, provide an accurate wayof measuring two tremor indices; the frequen-cy of the principal peak in a spectrum and themagnitude (root mean square acceleration) ofthat peak.

There are several specific reasons why theraters produced better correlations thanaccelerometry with the patients' self-reporteddisability:

Firstly, the accelerometers used could onlyrecord postural upper limb tremor in one spa-tial dimension (vertical). This deficiencycould have been avoided by using triaxialaccelerometry, albeit at greatly increased costand complexity. Second, the raters were ableto appreciate the behaviour of the whole limbwhereas the accelerometer can only reflectactivity at one site. Third, and perhaps mostsignificantly, the raters were all greatlyimpressed by what looked like intermittent"jumps" of the patients' hands. These infre-quent, "aperiodic" but sudden increases intremor amplitude would be the events mostlikely to cause a patient to spill a cup of coffeeor ruin a piece of writing. However, these lowfrequency, high displacement components,characteristic of essential tremor as well asdystonia,19 produced little effect on the domi-nant peak of the averaged spectra obtained byaccelerometry.

Assessments of spirography and handwrit-ing impairment were highly correlated withone another and with disability as well as withright upper limb postural tremor grades (table2). Furthermore, the inter and intra-rater reli-abilities for these two tasks varied from fair toalmost perfect. In each case one rater per-formed well below the level of the other three;had this not been the case both inter andintra-rater agreements would have beenalmost perfect. In spite of this, assessment ofeither spirography or handwriting provides avalid and convenient measure of the disabilitycaused by postural tremor. Spirography couldbe developed to provide a quick and practicalway of reassessing patients by postal survey,providing the way in which a spiral is drawnhas been standardised beforehand. The use ofspirography in this way has the advantages ofconvenience and cost. It is more likely toreflect the day to day state of a patient'stremor because it avoids the anxiety thataccompanies hospital attendance. The poten-tial for a systematic bias caused by a trainingeffect is also minimised because most patientswill have learnt to write and draw in child-hood and have practiced subsequently. It isthus unlikely that their performances willimprove during the course of a clinical trialmerely because of a training effect. In con-trast, hospital based accelerometric assess-

ments have been shown to produce a signifi-cant trend towards lower tremor amplitudesat successive evaluations in untreated patientswith essential tremor.20 Consequently,accelerometry will overestimate the beneficialeffect of both drugs involved in a comparisonstudy (for example, propranol versus primi-done) and also the effects of treatment andplacebo in a double blind placebo-controlledcross over study.A feature of this clinical rating scale is the

way in which tremor magnitude is related tospecific anatomical sites. We suggest thatwhen using it the individual scores for tremorseverity at different sites are not amalgamatedor averaged. Retention of the separate identi-ties of the scale's components preventsunnecessary loss of useful information aboutthe differential responses or natural historiesof these site specific tremor components. Forinstance we found that in those patients withhead tremor, eight of whom had torticollis,the severity of head tremor correlated poorlywith that of postural tremor in the right upperlimb (correlation coefficient: 0227); suggest-ing that they are produced by two separatebut associated mechanisms.As tremors all vary continuously with time

and with the position and state of activity ofthe patient's limbs, it is perhaps not surpris-ing that neurologists appear to be better thanaccelerometry at evaluating such complexfour dimensional behaviour in terms of itseffect on people's lives. We conclude that, forthe purposes of therapeutic trials, a clinicalrating scale can produce reliable results,which are a more valid index of tremorinduced disability than standard posturalaccelerometry. Consequently, emphasis onaccelerometry should be avoided. The vali-dity of accelerometry could possibly beimproved upon by recording during specifictasks, such as spirography or a tracking task(rather than a standard posture), but thisremains to be established. Grading spiro-graphy and handwriting would appear to beuseful because the impairment seen in thesetasks correlated well with disability.Standardising the way in which a spiral isdrawn and improving analytical methodscould lead to a way of carrying out postalassessments.

In this study we have demonstrated that aclinical rating scale can be analysed by a sta-tistical method to provide a measure of theinter and intra-rater reliability of the specificraters involved. This information could becritical to the design of a therapeutic trial; asit allows the trial organisers to drop specificraters and/or switch to a different (more reli-able) method of assessment. It also providessome indication of the number of patientsrequired to show a specific magnitude of ther-apeutic effect. Without this information theresults of any trial depending upon a clinicalrating scale could be questioned.No other tremor rating scale has been

evaluated for inter and intra-rater reliabilityor been shown to be valid as an index of dis-ability.

872

on Septem

ber 7, 2020 by guest. Protected by copyright.

http://jnnp.bmj.com

/J N

eurol Neurosurg P

sychiatry: first published as 10.1136/jnnp.56.8.868 on 1 August 1993. D

ownloaded from

Assessing tremor severity

Appendix 1

The rating scale: An example is shown of a patient with grade 5 pos-

tural tremor (P) and grade 1 rest tremor (R) of the right upper limb.An identical system was used for grading tremor of the other limbs,voice and head.

We thank the nursing staff of the outpatient department of theNational Hospital for Neurology and Neurosurgery, QueenSquare, London, for their assistance during the grading clinicand Drs Richard Brown and Marian Jahanshahi for theirexpert statistical help. Dr Peter Bain is supported by a grantfrom the Welcome Trust.

Right upper limb

Extremely Severe 10

Severe

Moderate

Mild

9-

8

7-

6-

5 -kP

I4

3

2-

1 R

None 0

Appendix 2Illustrates the activities of daily living self-questionnaire. The righthand column shows the percentages of patients reporting difficultieswith each item.

Activities of daily living:For each item circle the number which describes how easy or difficult it is for you to performthe activity.

1 Cut food with a knife and fork.2 Use a spoon to drink soup.3 Hold a cup of tea.4 Pour milk from a bottle or carton.5 Wash and dry dishes.6 Brush your teeth.7 Use a handkerchief to blow your nose.8 Use a bath.9 Use the lavatory.10 Wash your face and hands.11 Tie up your shoelaces.12 Do up buttons.13 Do up a zip.14 Write a letter.15 Put a letter in an envelope.16 Hold and read a newspaper.17 Dial a telephone.18 Make yourself understood on the telephone.19 Watch television.20 Pick up your change in a shop.21 Insert an electric plug into a socket.22 Unlock your front door with the key.23 Walk up and down stairs.24 Get up out of an armchair.25 Carry a full shopping bag.

Percentage ofpatientsreporting difficultywith each item

1 2 3 4 501 2 3 4 651 2 3 4 801 2 3 4 451 2 3 4 201 2 3 4 201 2 3 4 01 2 3 4 401 2 3 4 101 2 3 4 101 2 3 4 151 2 3 4 351 2 3 4 201 2 3 4 701 2 3 4 451 2 3 4 601 2 3 4 401 2 3 4 51 2 3 4 51 2 3 4 401 2 3 4 151 2 3 4 301 2 3 4 401 2 3 4 351 2 3 4 45

1 Webster DD. Critical analysis of the disability inParkinson's disease. Mod Treatment 1968;5:257-82.

2 Duvoisin RC. The evaluation of extrapyramidal disease.In: de Ajuriagerra J and Gauthier G, ed. Monoamines,noyaux gris centraux et syndrom de Parkinson. Paris:Masson, 1970:313-25.

3 Lieberman A, Dziatolowski M, Gopinanthan G, et al.Evaluation of Parkinson's disease. In: Goldstein M,Calne DB, Lieberman A, Thorner MO, eds. Ergot com-ponents and brain function: neuroendocrine and neuropsy-chiatric aspects. New York: Raven Press, 1980;277-86.

4 Fahn S, Elton RL, and members of UPDRS committee.Unified Parkinson's disease rating scale. In: Fahn S,Marsden CD, Goldstein M, Calne DM, eds. Recentdevelopments in Parkinson's dsease (2). New York:Macmillan, 1987:153-163 and appendices I and II.

5 Koller WC. Dose response relationship of propranolol inthe treatment of essential tremor. Arch Neurol 1986;43:42-3.

6 Cleeves L, Findley U. Propranolol and propranolol LA inessential tremor: a double-blind comparative study. YNeurol Neurosurg Psychiatry 1988;51:379-84.

7 Muenter MD, Danbe JR, Miller PM. Treatment of essen-tial tremor with Methazolamide. Mayo clin proc 1991;66:991-7.

8 Findley U, Cleeves L, Calzetti S. Primidone in essentialtremor of the hands and head: a double-blind controlledclinical study. Y Neurol Neurosurg Psychiatry 1985;48:911-5.

9 Landy FJ, Farr JL. Performance rating. Psychol Bull1980;87:72-107.

10 Nunnally JC. Psychometric Theory. New York: McGrawHill, 1967:519-28.

11 Sangalli A. Fuzzy logic goes to market. New Scientist1992;1807:36-9.

12 Koller W, Findley LJ, de Witt P, Elble R, Jankovic J, LangA, Rajput A, (Tremor research group: TRIG).Classification and definition of tremor. World Neurology1993; (Newsletter of the World Federation ofNeurology) (In press).

13 Brown RG, MacCarthy B, Jahanshahi M, Marsden CD.Accuracy of self-reported disability in patients withparkinsonism. Arch Neurol 1989;46:955-9.

14 Brown RG, MacCarthy B, Gotham AM, Der GJ,Marsden CD. Depression and disability in Parkinson'sdisease: a follow-up of 132 cases. Psychol Med 1988;18:49-55.

15 Hewlett-Packard. Digital Signal Analyser: user's guide.HP05420-900, 1978.

16 Francis DA, Bain PG, Swan AV, Hughes RAC. Anassessment of disability rating scales used in multiplesclerosis. Arch Neurol 1991;48:299-301.

17 Landis JR, Koch GG. The measurement of observeragreement for categorical data. Biometrics 1977;3:159-73.

18 Hall JN. Inter-rater reliability of ward rating scales. Brit JPsychiat 1974;125:248-55.

19 Critchley E. Clinical manifestations of essential tremor. JNeurol Neurosurg Psychiatry 1972;35:365-72.

20 Cleeves L, Findley U. Variability in amplitude of untreat-ed essential tremor. J Neurol Neurosurg Psychiatry 1987;50:704-4.

KEY: 1 Able to do the activity without difficulty.2 Able to do the activity with a little effort.3 Able to do the activity with a lot of effort.4 Cannot do the activity by yourself.

873

on Septem

ber 7, 2020 by guest. Protected by copyright.

http://jnnp.bmj.com

/J N

eurol Neurosurg P

sychiatry: first published as 10.1136/jnnp.56.8.868 on 1 August 1993. D

ownloaded from