Age and Ageing 1988;17:111-115

P.W.MCHOLBON PRESSURE SORES: EFFECT OFSKtSKiSS1" PARKINSON'S DISEASE AND

COGNITIVE FUNCTION ONSPONTANEOUS MOVEMENT IN BED

TeetinWan J.P.ROVSTON R.J.D0B88o u nnaas* Statistician Senior RegistrarL n l ^ Registrar Therapeutics In the Elderty Department of MedicineSenior Hegistrar Research Group end *w «*"> Elderty. BametA. A. MSHMUKHt Division of Medical Statistics. Goneral Hospital, BarnetVisiting Research Worker Q , ^ , p ^ g , ^ (;„«„,, Northwick Hertfordshire. EN5 3DJM. J. DBIHAM Park Hospital. Harrow,Consultant Middlesex HA1 3UJ

SummaryIt has previously been shown that the incidence of pressure sores is related inversely to the amount ofmovement made during the night. The present study of 30 in-patients of geriatric units suggests that themeasurement of mean lateral displacement of the centre of gravity may better characterize those at riskthan the total amount of movement. The mean displacement was reduced in Parkinson's disease and indementia. The prevalence of pressure sores was markedly increased where Parkinson's disease anddementia coexisted. —

INTRODUCTION

Prediction of which patients are at risk of developing pressure sores would allowpreventive measures to be properly focused. In 1962, Norton and co-workers [1]introduced a score for the risk of pressure sores, based on nursing observation ofgeneral condition, mental state, continence and daytime mobility. This is still widelyused. However, Pritchard [2] found that, in a geriatric unit, the Norton Score didnot distinguish adequately those at risk. Exton-Smith and Sherwin [3] have shownthat the occurrence of pressure sores was related inversely to a measure of the totalamount of spontaneous movement made during the night. We have studied thenight-time mobility of in-patients of geriatric units, recording the lateral displace-ment of the patient's centre of gravity using a simplified version of the apparatus ofBarbenel et al. [4] for solid-based beds. Particular reference is made to Parkinson'sdisease since sufferers from this condition find particular difficulty with axialrotation, whether they are upright or recumbent and despite otherwise adequatelevodopa therapy [5].

Patients and Methods

Movements in bed were recorded on 4 nights in clinically stable patients undergoing rehabilitation orrequiring continuing nursing care, those with hemi-, para- or tetraparesis being excluded. The night-time movements of all eligible patients with Parkinson's disease presenting during a 6-month periodwere monitored, as were those of a randomly-selected group of other eligible patients from the same

•Address correspondence to Dr S. M. Dobbs.•(•Present appointment: Lecturer in Pharmaceutics, School of Pharmacy, Brunswick Square, Lon-

don, WC1N 1AX.

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112 AGE AND AGEING VOL. 17, NO. 2

wards. Cognitive function was assessed using the modified Tooting Bee questionnaire, a short cognitivefunction test designed to test memory, orientation and concentration in geriatric units [6]. Thefollowing were noted: a diagnosis of arthritis of any type, the presence of pain, whether or not a hypnoticwas being taken and any existing pressure sores.

Assessment of movement in bed

A system with a load-transducer under each bed leg was used to obtain a continuous plot of the lateralposition of the patient's centre of gravity [7]. Each transducer consisted of a cantilever, whose deflectionwas sensed by a resistive strain gauge. The four strain-gauge resistor elements were connected in abridge configuration so that the out-of-balance signal was related linearly to the position of the patient'scentre of gravity across the bed. The signal was amplified, filtered, and displayed on a chart recorder togive a continuous plot of the position of the centre of gravity. The records for the hour after retiring tobed and the hour before arising in the morning were eliminated from the analysis. Rising from andreturning to bed during the night produced characteristic deflections: 10-min periods before and afterthese events were also discarded. A section of trace of the same length was discarded around the timeswhen the subject received attention during the night.

The absolute displacement of the patient's centre of gravity was calculated from body weight and acalibration by known weight. A displacement as small as 4 mm could reliably be detected. Onlydisplacements greater than this, and sustained for 1 min or longer, were used in the analysis. Drifts ofthe pen, defined as movements not completed within 0.5 min or less, were not analysed. For each nightstudied the number of moves by the patient greater than 4,10 and 20 mm were counted and all distancesof more than 4 mm were summed. These values were adjusted proportionately according to the lengthof record analysed. The mean size of the movements was calculated.

Statistical methodsThe significance of associations between the characteristics of patients and the measures of their

movement in bed were assessed by calculating Spearman's nonparametric correlation coefficients. Therelationship of mean move size to the cognitive function score and the presence or absence of Parkin-son's disease was examined by multiple linear regression analysis.

RESULTS

Of the 30 patients studied, 12 had Parkinson's disease, 21 had a history of arthritis,which was a major problem in ten. Seventeen complained intermittently of pain,which was severe in four. The pain was attributed to arthritis, leg ulcers, cellulitis orcramps and was being treated accordingly. Eleven patients were receiving hypnotics.Seven had superficial pressure sores. The mean (s.d.) age was 82 (7) years and meanscore out of 16 for the modified Tooting Bee Questionnaire was 7 (5). It is interest-ing to note that all seven patients with superficial pressure sores had Parkinson'sdisease. The increased frequency of pressure sores in those with Parkinson's diseasewas highly significant (Fisher's exact test, P<0.001).

Associations between movements in bed and patient characteristics are given inthe Table.

Size of movementsPatients with poor cognitive function and/or Parkinson's disease made relatively

small movements: the mean move size of the 19 patients with a cognitive functionscore of 3 or less and/or Parkinson's disease [13 (5)mm] was approximately half thatof the remainder of the group [25 (24)mm]. Those with Parkinson's disease as agroup did not have significantly lower cognitive function scores than the rest of the

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NICHOLSON ET AL.: PRESSURE SORES 113

Table. Factors influencing movements in bed in 30 patients of a geriatric unit: the relationship betweenpatient characteristics and frequency and size of movements in bed (mean values for threeconsecutive nights) is expressed in terms of Spearman's rank correlation coefficient

Patient characteristics

Age (years)Cognitive functionIdiopathic Parkinson's disease'*'Arthriti8++

Pain++

Receiving hypnotic+++

Superficial pressure score+

Number of moves

>4 mm

0.06-0.37#

-0.060.02

-0.17-0.27

0.05

>10 mm

-0.02-0.17-0.26

0-03-0.06-0.15-0.15

>20mm

-0.050.03

-0.310.090.030.02

-0.21

Totaldistance

- moved(mm)

-0.06-0.20-0.13

0.03-0.09-0.15-0.07

Meanmovesize

(mm)

-0.260 .54"

-0.36*0.200.43*0.30

-0.41*

V<0.05;+Scored as absent 0, present 1.++Scored absent 0, present 1, major problem 2.+++No 0, yes 1. [Eleven patients were receiving nocturnal doses of hypnotic (or sedative) drugs;

chlormethiazole in 3, temazepam 2, nitrazepam 2, thioridazine 2, diazepam 1 and dichloralphenazone1]

patients (r=—0.134, P>0.1) : thus these two characteristics appeared to have inde-pendent influences on movement size. However, when the cognitive function scoreand the presence or absence of Parkinson's disease were included simultaneously in amultiple regression equation, only the score had a significant (/><0.01) effect onmean move size. Each additional point scored corresponded to an increase of 5% (onaverage) in the mean move size.

Number of movementsThe number of movements correlated inversely with the cognitive function score:

the 12 patients with a score of 3 or less made nearly twice as many moves per hour[mean 9 (6)] as those with a higher score [5 (3)]. The number of moves made bypatients with Parkinson's disease was not significantly different from that made bythe other patients.

Pressure soresIn the patients with pressure sores, pain had been controlled by non-narcotic

analgesics. These patients had a significantly smaller mean move size [11 (2)mm]than the rest of the group [19 (16)mm]. In patients who were suffering pain, themean size of move was significantly greater [21 (18)mm] than in those who werepain free [12 (4) mm]. This may well represent an attempt to find a more comforta-ble position.

Hypnotics

We did not evaluate quality of sleep in this study but there was no objectiveevidence in terms of reduction of movement in bed (see Discussion) to suggest thatthose who received hypnotics slept better than the rest of the group.

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114 AGE AND AGEING VOL. 17, NO. Z

DISCUSSION

The amount of spontaneous movement exhibited in bed by our patients wasremarkably small. Since movement of a limb, not accompanied by movement of thetrunk, can displace the patient's centre of gravity laterally, many of the smalldisplacements recorded would not have been accompanied by any useful relief ofpressure on soft tissue in vulnerable areas. Indeed, our patients with pressure soreshad a significant reduced mean move size compared with the others, but did notdiffer from them with respect to number of moves made or total distance moved.Further work is required to determine whether axial rotation is a more usefulpredictor of the risk of developing pressure sores than is lateral displacement ofcentre of gravity, and to investigate the relative importance of nocturnal mobility andother risk factors.

All those with pressure sores had both Parkinson's disease and dementia.However, the major determinant of mean move size in the group as a whole wasdementia, the presence or absence of Parkinson's disease having no additional effect.Increased shearing stress in the skin, consequent on tremor or rigidity in the adjacentmuscle, may have added to the susceptibility to pressure sores of those with coexist-ing Parkinson's disease.

The total amount of movement in bed decreases during sleep [8], the magnitudeof the effect being dependent on the depth of sleep [9, 10]. A good night's sleep isassociated with a decrease in the number of moves made, but there is no change inmean move size [11]. Hypnotics such as barbiturates, meprobamate and flurazepamhave been shown to reduce the total excursion made by individuals during the night[12-14] but we were unable to detect any difference in movement between agedin-patients who did, and did not, receive hypnotic and sedative drugs. However, adifferent spectrum of drugs for night sedation was in use. The increased frequency ofsmall movements found in dementia presumably simply reflected the particularlysevere fragmentation of sleep found in dementia in old age [15].

REFERENCES

1. Norton D, McLaren R, Exton-Smith AN. Pressure sores: Part 1. A study of factors concerned inthe production of pressure sores and their prevention. In: An investigation of geriatric nursingproblems in hospital. London: National Corporation for Care of Old People, 1962;194—238.

2. Pritchard V. Pressure sores: calculating the risk. Nurs Times 1986;82:59-61.3. Exton-Smith AN, Sherwin RW. The prevention of pressure sores: significance of spontaneous

bodily movements. Lancet 1961;2:1124-6.4. Barbenel C, Ferguson-Pell MW, Beale AQ. Monitoring the mobility of patients in bed. Med Biol

EngComput 1985 ;23:466-8.5. Lakke JPWF, de Jong PJ, Koppejan EH, et al. In: Rinne UK, Klinger M, Stamm G, eds.

Parkinson's disease: current progress and management. Elsevier/North Holland BiomedicalPress, 1980; 187-96.

6. Denham MJ. Routine normal testing in the elderly. Medicine 1978;1:1.7. Nicholson PW, Rosenthal M, Jordan A, et al. Pressure sores: relationship of drug treatment and

illness to spontaneous movement during the night. BrJ Clin Pharmacol 1986;22(2):224-5P.8. Cox GH, Marley E. The estimation of motility during rest or sleep, J Neurol NeurvsurgPsychiatry

1959;22:57-60.

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9. Loomis AL, Harvey EN, Hobart GA. Cerebral states during sleep as studied by human brainpotentials. J Exp Psychol 1937;21:127-44.

10. Blake H, Gerard RW, Kleitman N. Factors influencing brain potentials during sleep. J Neuw-pkysiol 1939;2:48-60.

11. Leeman AL, O'Neill CJA, Nicholson PW, et al. Parkinson's disease in the elderly: response to andoptimal spacing of night time dosing with levodopa. BrJ CHn Pharmacol 1987-,24:637-44.

12. Hinton JM, Marley E. The effects of meprobamate and pentobarbitone sodium on sleep andmotility during sleep: a controlled trial with psychiatric patientB. JNeunlNeurosurgPsychia-try 1959-.22:137-40.

13. Hinton JM. The actions of amylobarbitone sodium, butobarbitone and quinalbarbitone sodiumupon insomnia and nocturnal restlessness compared in psychiatric patients. BrJ Pharmacol1961;16:82-9.

14. Crowley TJ, Hydinger-Macdonald M. Bedtime flurazepam and the human circadian rhythm ofspontaneous motility. Psychopharmacology 1979;62:157-61.

15. Allan SR, Stahelin MB, Seiler WO, et al. EEG and sleep in aged hospitalised patients with seniledementia: 24 h recordings. Experientia 1983;39:249-55.

Date accepted 20 June 1987

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