J Child Psychol Psychml. Vol. 34, No. 2, [.p. 255-261, 1993 0021-9630/93 »6.0n * 0.00Printed in Grcal Britain Pergamon Press Ltd

© 1993 Associaiion for Child Psyt:holog\ and P^ychUlry

Handedness Distribution and FigureDrawing Ability in a Deaf SchoolPopulation, with Severe Learning

Difficulties: a Research Note

Paul Arnold and Samantha Askew

Abstract—T\ie: handedness distribution of 71 deaf pupils with severe learning difficulties,was found to be similar to that reported by Soper et al. (1987, American Journal of MentalDeficiency, 92, 94-102) in a mentally handicapped sample, who also found a high incidenceof ambiguously handed individuals, Soper's theory, however, that the "acquired" left-handed and the ambiguously-handed are more handicapped and so, we might infer, drawmore primitive human figures, was not supported. The left, ambiguously-handed and right-handed had the same scares on human figure drawing. Neither was there a difference inhandedness or figure drawing between the "acquired", the "genetic" and the "unknown"cause groups; nor between males and females.

Keywords: Handedness, deafness, learning difficulties, mixed handedness

Pipe (1990) has reviewed 23 papers, published between 1912 and 1989, on learningdisability and handedness. Her conclusion was that the data "show that the incidenceof left and mixed-handness among nientally retarded groups is approximately doublethat in non-retarded comparison groups . . . " Pipe also concluded that "it also seemslikely that in retarded groups pathological left-handedness is not a unitary phenomenaalthough it has been generally treated as such."

Satz, Soper & Orsini (1988) propose three nondextral subtypes. These arepathological left-handers; "ambiguous handers" caused by early bilateral damage;and natural left-handers. The ambiguously-handed subtype was first identified ina subset of the autistic population who were found to have no established manualdominance (Satz, Soper, Orsini, Henry & Zvi, 1985; Soper & Satz, 1984; Soper ^̂al, 1986). Defming consistent hand preference as making 90% of unimanuai responses

Accepted manuscript received 19 February 1992

Department of Psychology, University of Manchester.Reque.'its for reprints to: Dr Paul Arnold, Department of Psyehology, University of Manchester, ManchesterMI3 9PL, U.K.

255

2 5 6 P, Arnold and S. Askew

with the same hand, Satz et al. (1988) found 36% of subjects who showed no consistencyin hand preference within or between sessions, or even within items. They hypothesisedthat this ambiguous handedness was due to severe early bilateral brain damage,primarily in natural right-handers, which prevented the establishment of manualdominance and cognitive development. They continue, "Although the putative brainlesion remains to be confirmed by anatomic or metabolic imaging techniques, threerecent studies have shown that this ambiguous or mixed dominant subtype representsa more cognitively impaired subgroup compared to autistic children with establisheddominance (left-or right-handed)". Soper f̂ a/. (1987, p. 96) also cited studies (Feinet ai, 1984; Soper et al., 1986; Tsai, 1982; Zvi, Schulman & Soper, 1984) to arguethat ambiguously handed autistic individuals represent a more cognitively impairedsubgroup than those with established left- or right-handedness. In the same paper,Soper et al. (1987) demonstrated that ambiguous handedness was not confined toautistic populations but was also found within the nonautistic mentally retardedpopulation.

Myklebust (1964) examined the relationship between left-handedness and deafness.He tested 219 residential school children, and found 12.8% to be left-handed. Hesuggested that neurological disorders associated with deafness were responsible, andnoted that those children whose deafness appeared to be hereditary and who are lesslikely to suffer from additional neurological damage are no more left-handed thanhearing children. Conrad (1979, pp. 65-69) agreed with this, and suggested thatbrain injured deaf individuals are more likely to be left-handed than those whosedeafness is genetic in origin. Conrad (1979) recorded the hand which each child usedin writing, and found 17% wrote with their left hand. When Conrad analysed therelationship between handedness and cause of deafness, he found that of the hereditarydeaf, only 10.2% wrote with their left hand. For those with acquired and unidentifieddeafness the value almost doubled. Conrad's results supported Myklebust's suggest:ionthat neurological disorder may be associated with acquired deafness. Those withhereditary deafness and who are least likely to suffer from additional neurologicaldisorders are no more left-handed than hearing children.

Conrad also found an association between handedness and additional handicap.In his sample 14.9% of the children (n = 382) without other handicap were left-handed,while 26.7% of those with an additional handicap (n = 86) wrote with their left hands.This is almost three times the value for hearing children, and almost double the valuecited by Satz (1972) for mentally retarded and epileptic hearing groups.

Bonvillian, Orlansky and Garland (1982) used a questionnaire to compare thehandedness patterns of 226 (nonhandicapped) deaf students with those of 210 normallyhearing college students, and found a significantly higher incidence of left-handednessamongst the deaf. They found that the age of acquisition of language related tohandedness distribution and wrote, "Thus, the overall pattern that emerges for theleft-handed deaf subjects appears to one of relatively little language usage and exposureduring the early childhood years." When those deaf subjects who learned to signbefore six years of age were compared with those who reported learning at six yearsor older, the latter were more left-handed. Also the correlation between reported ageof sign language acquisition and the deaf subjects' overall hand preference scoreswas statistically significant, although small in magnitude.

Handedness in deaf SLD 257

Human figure drawing has been used as a nonverbal measure of cognitivedevelopment and also of brain damage (Goodenough & Harris, 1963). Myklebust(1964) carried out a study of 822 deaf pupils, using the Draw a Man Test (Goodenough,1926), and found that the scores ofthe deaf and hearing children were similar. Thetest is a nonverbal intelligence test and is based on the unaided normal developmentalsequence of children's figure drawing ability. Recently Cox and Howarth (1989)examined human figure drawing of normal children and those with severe learningdifficulties. One ofthe earliest recognisable forms to appear in children's drawingsis the human figure. Their first attempts have been called tadpoles, or tadpole figuresand are typically drawn by normal children around the age of 3-4 years. By the ageof 5, and certainly by 6 years, most children produce a conventional human figurewith distinct head and body segments. Representational figure drawing involves fmemotor control, memory, serial sequencing and spatial integration, and so it is notsurprising that young children's drawings are rather crude. Cox and Howarth foundthat the nonrepresentational and representational drawings of children with severelearning difficulties are similar to those found in normal children. They look similarand are constructed in a similar way, which suggests that the drawings of childrenwith severe learning difficulties (SLD) reflect a developmental delay.

The literature on handedness in mental retardation and deafness suggests that thelearning disabled children with hearing impairment should show a high incidence ofnonright-handedness, including pathological left-handedness and ambiguoushandedness. This study set out to study that prediction.

Method

Subjects

Thf subjects were 71 multiply handicapped deaf pupils from the Royal Schools for the Deaf, CheadleHutnie; one ofthe two schools for them in Britain, Their ages ranged from 6 to 23 (range = 17), meanage= 13 19 S D =4.3, There were 47 males and 24 females. Hearing losses ranged from 40 to130 dB, with a mean loss in their better ear of 106 dB (S.D. = 16,77) at 500, 1000, 2000 and 4000Hz. Only four had losses of less than 80 dB. The cause of their deafness was acquired {n = 37), or genetic{n = 8) and unknown {n = 26),

MaterialsThe materials used to assess handedness were: a plastic play hammer; a plastic cup with a handle;

a plastic spoon (normal sized); a lOp piece; toothbrush (and antiseptic fluid); a sponge ball; chocolatesweets; crayons and pens (depending on the subject's ability to grip), and sheets of white paper, 1 6 x 1 2

Procedure

The "Hand Preference Demonstration Test" (HPDT) (Soper et at., 1986) was administered. The(asks required the following: (A) A spoon which the child had to use to illustrate eating, (B) A cupof water, with which the child had to give a demonstration of drinking. (C) A toothbrush which theyhad to either brush or pretend to brush their teeth with, (D) A crayon or pencil, with which they hadto draw, (E) A sponge ball, which the child had to throw. (F) A plastic hammer with which the childhad to demonstrate their hammering skills, (G) A sweet which the child had to pick up, (H) A coinwhich they had to pick up.

258 p. Arnold and S, Askew

Subjects were also required to draw a human figure.The instructions were both spoken and given in British Sign Language. The subject was asked to

pick the item up, which usually elicited the appropriate action. If this failed the teacher asked a morespecific question such as "What do you do with this?", which initiated a response. With the ball, theywere required to stand up and be asked to "Throw the ball to me". With the sweet the child was askedto eat it, and with the coin they were asked to "Give it to me".

All subjects were tested individually in their own classrooms, at a separate desk, away from others.They sat opposite the experimenter and their teacher was always present. The test consists of eightitems presented in a random sequence, one by one with both hands, to inhibit mirror responding, threetimes each, making a total of 24 possible responses,

Soper et al. (1987) found that their learning disabled subjects tended to be consistent in lateraiityscores across their two testing sessions, with a Pearson Product-Moment Correlation of .86. None shiftedfrom one handedness group (left or right) to the other from one session to the next. The study hadonly one session. The Laterality Index developed by Soper et al. (1986) was based on the proportionof right-handed responses to the total unimanual responses (right plus left) times 24 (the maximumnumber of responses in any category) [LateraJity index = (right hand unimanual responses/all unimanuaJresponses) X 24], This index yields a range of scores from 0 (consistent left-hand preference) to 24(consistent right-hand preference). Subjects were classified as left-handed if 90% of their unimanualresponses were made with that hand (Laterality scores of 0-2.5). Conversely, subjects were consideredto be right-handed if 90% or more of their responses were made with that hand (Laterality Index scoresof 21.5 to 24), An individual whose score was between these two extremes was considered to bemixed-handed.

Soper et al. (1986) distinguish between two kinds of mixed-handedness; ambiguous and ambidextrcus.A subject is classified as ambiguously handed if they were inconsistent on more than two within- itemresponses, and not just between- items responses of the items of the HPDT.

Subjects were also required to draw a human figure. Judges classified each drawing into one of livecategories, on Cox and Howarth's criteria: (1) scribbles, (2) scribble, but with distinct forms, (3) tadpole,(4) transitional, and (5) conventional (Cox & Parkin, 1986).

Results

Using Soper et al. 's (1987) criterion of handedness 10 (14.1 %) were left-handed,24 (32.4%) right-handed, and 37 (53.5%) were mixed-handed.

Of the 36 mixed-handed subjects 29 were inconsistent on more than two of theeight items ofthe HPDT, i.e. they showed ambiguous handedness. No subjects weretruly ambidextrous (variable between items, but not variable within items). Thesubjects in the mixed group all failed to show stability in manual preference.

The handedness distributions ofthe three groups based on the cause of deafness;acquired, genetic and unknown were calculated. Ofthe 37 "acquired" subjects 7were left-handed, 18 mixed-handed and 14 right-handed. Ofthe 8 "genetic" deaf5 were mixed-handed and 3 right-handed. Ofthe 26 "unknown" 3 were left-handed,15 mixed-handed and 8 right-handed. It can be seen that 19% ofthe acquired groupwere left-handed compared with none ofthe genetic deaf, and of 11 % ofthe unknowngroup.

On human figure drawing 23 (32.4%) subjects produced "scribbles", 12 (16.9%),"scribbles with some form", 14(19.7%) "tadpoles", 2 (2.8%) "transitional" and20 (28.2%) "conventional". Handedness scores were transformed by taking eachscore's deviation from the central point of 12, these were correlated with the humanfigure drawing type scores. The Pearson Product-Moment Correlation between theoverall (deviation from 12, the midscore on the scale) handedness scores and the human

Handedness in deaf SLD 259

uc0)3cr

10 12 14 16

laterality indexFig, 1, Distribution of hand preference scores.

20 22 24

figure drawings (.08) was not significant. One way analyses of variance between thethree handedness groups; right, mixed and left, on drawing, showed no statisticallysignificant differences. Also within the mixed-handedness group, the ambiguously-handed and the remainder did not differ on the human figure drawing task.

One way analysis of variance, using the Scheffer Test for specific comparisons,between the scores of the acquired (mean 2.27; S.D. = 1.4), genetic (mean 3.0;S.D. = 1.9), and unknown (mean 3.42; S.D. = 1.6) groups on human figure drawing,showed a significant difference only between the acquired and unknown groups(p<.05).

Males and females were not significantly different on a one way analysis of variance,in handedness, figure scores or in the cause of their deafness.

The 18 severely deaf were compared with the 50 profoundly deaf on a one wayanalysis of variance, which showed there was not statistical difference in handednessbetween them (severe: mean 34.6, S.D. = 15.2; profound: mean 29.8, S.D. = 18.3);and no statistical difference on the figure drawing test (severe: mean 2.63, S.D. = 1.5;profound: mean 2.81, S.D. = 1.6). The younger (less than 13) and older (13 yearsand over) subjects were compared on a one way analysis of variance. There was nostatistically significant difference between the 33 younger and 38 older subjects intheir degree of handedness or figure drawing ability (p < .06), although these werein the expected direction. The handedness means for the younger was 33.9(S.D. = 16.1) and for the older 28.1 (S.D. = 17.9). For figure drawing, the mean forthe younger group was 2.39 (S.D. = 1.5); and for the older group, 3.1 (S.D. = 1.7),which were not significantly different (p<0.06), although again in the expecteddirection.

260 P. Arnold and S. Askew

Discussion and Conclusion

The population is one with severe learning difficulties together with severe orprofound deafness. In the present study the term mixed-handed refers to those whodo not meet the 90% criterion for left- or right-handedness (A^= 37), and ambiguouslyhanded to refer to those who were inconsistent on more than two within-item responses(A^= 29). The distribution was similar to that found by Soper et al. (1987) in severelymentally retarded adults. In the present study the percentage of left-handers was 14.4%(Soper found 9.6%); mixed-handed 53.5% (Soper 45.2%); and right-handed 32.4%(Soper 45.2%). Soper et al. (1987, p. 97) note that their distribution "differssubstantially from an expected normal distribution of 8% left-handedness, 0%ambiguous handedness and 92% right-handedness". The histogram (Fig. 1) is alsovery similar in form to that of Soper et al. '& subjects and also to Soper et al. 's (1986)autistic sample.

These findings contribute to an answer to Soper et al.'s (1987, p. 96) statementthat "The problem remains as to whether a mixed or ambiguously handed subtypealso exists with the nonautistic mentally retarded population or whether this ambiguoushandedness phenotype is unique to autism." The present fmdings confirm Soperet al. 's (1987) fmding that a mixed or ambiguously subtype does exist and that it isnot a phenomenon unique to autism. In fact, this general view has some supportfrom Soper et ai (1987, p. 99) themselves. They had scores from the McCarthy Scalesof Children's Abilities or the Bayley Scales of Infant Development, Mental Scale,from another related study, for 7 left-handers, 25 ambiguous handers and 27 right-handers. They write "Surprisingly, the scores of the right-handers (mean = 28.1months) and the ambiguous handers (mean = 27.8 months) subgroups were almostequivalent. However, the scores for the left-handed subgroup were significantly lower(mean of 17 months) than either of the other two groups."

Soper et al.'s (1987) finding of a high incidence of ambiguous handedness wassupported. The ambiguously-handed and the left-handed with acquired deafness weregenerally not, however, more cognitively disabled on human figure drawing, relativeto right-handers.

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Conrad, R. (1979). The deaf schoolchild. London; Harper and Row.Cox, M. & Howarth, C. (1989). The human figure drawings of normal children and those with severe

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