0362-1197/05/3105- © 2005

MAIK “

Nauka /Interperiodica”0539

Human Physiology, Vol. 31, No. 5, 2005, pp. 539–544. Translated from Fiziologiya Cheloveka, Vol. 31, No. 5, 2005, pp. 52–57.Original Russian Text Copyright © 2005 by Bezrukikh.

Handwriting is an integrated activity involving mul-timodal interaction between motor, visual-spatial, andlinguistic abilities [1]. Almost all cortical regions areinvolved in handwriting [2–6]. This suggests that thecauses and expressions of difficulties in the formationof the writing skill are multiple and various, the processbeing further complicated by the simultaneous forma-tion of the writing skill and verbal activity.

Difficulties in the formation of writing ability are aset of interdisciplinary problems of the physiology ofmovement, neurophysiology of motor activity organi-zation, and psychophysiology of learning. Analysis ofthese problems may help to understand better the mech-anisms of the development of new motor coordinationand the specificity of movement control in cases of def-icits of some regulatory links. Many elementary-schoolstudents face problems that impede the formation of theskill, especially at the initial stage of learning [7–11].Note that the problem is difficulties with skill develop-ment usually referred to as poor writing or poor hand-writing, rather than disorders.

To date, there is no consensus as to the causes ormechanisms of writing learning difficulties. Two maingroups of difficulties are distinguished: first, difficultiesrelated to the difficulties with speech development(mainly, the development of phonetic/phonemic atti-tude); second, difficulties determined by deficits in thedevelopment of motor functions, visual perception, andvisuomotor coordination [5, 11–16].

Specific disorders of cortical functions, minor cere-bral dysfunctions [4, 3, 17, 18], and disturbances ofinterhemispheric interactions and lateralization offunctions [19–22] are usually indicated as the neuro-physiological mechanisms of the emergence and devel-opment of these disturbances. However, disturbances of

the function that has already been formed in adults anddisturbances of the function that is being formed inchildren may have different mechanisms; this isextremely important and should certainly be taken intoaccount.

The relationship between the functional develop-ment of the brain and learning difficulties is one of themost complex, multifactorial, and widely discussedproblems. Although the very existence of this relation-ship is beyond question, there are controversial prob-lems, and many questions cannot be answered unam-biguously. One thing is obvious—learning difficultiesare never determined by disturbances of only one pro-cess; almost all of them are involved.

The first attempts to relate cortical electric patterns(the results of EEG analysis) directly to learning diffi-culties [2, 23] were not quite successful, although theyshowed the relationship between basic EEG character-istics and the known types of learning difficulties. Thiswas not unexpected, because the variation of the typesof learning difficulties, as well as the considerable vari-ation of the mechanisms underlying difficulties of thesame type, makes this analysis substantially more diffi-cult.

Further studies demonstrated that learning difficul-ties are related not so much to dysfunction of specificcerebral zones (the so-called partial defect) as to distur-bances of the coordination and integration of variousstructures and disturbances of the complex interactionbetween various functions [12]. The use of neurophys-iological methods made it possible to identify 21 vari-ants of learning disorders caused by different combina-tions of neurological deviations. Psychophysiologicaland neurophysiological studies confirmed the inte-grated nature of the mechanisms underlying various

Psychophysiological Mechanismsof Writing Difficulties in Schoolchildren

M. M. Bezrukikh

Institute of Developmental Physiology, Russian Academy of Education, Moscow, 119869 Russia

Received May 4, 2005

Abstract

—The temporal and qualitative organization of writing movements was studied in six- to seven-year-old and nine- to ten-year-old right-handed and left-handed children with underdeveloped visuomotor coordina-tion. The characteristic features of the temporal and qualitative organization of these movements at differentstages of motor skill formation were found. Regarding the temporal structure of the series of writing move-ments, a pause was observed between individual movements in the series of motor task formation. The durationof this pause may serve as a criterion of the degree and efficiency of writing skill formation. The disturbance ofthe temporal structure of movements during the formation of handwriting speed at the initial stages of learningdeteriorated the temporal organization of movements, drastically decreased the quality, and impeded the for-mation of the skill. The destructive processes were more pronounced in the case of accelerated handwriting inleft-handed children and especially in children with underdeveloped visuomotor coordination.

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learning difficulties [3, 6, 11, 20, 24–27]. It should alsobe emphasized that the writing skill is formed only inthe course of learning; however, the existing standardcurriculum and strict requirements of the organizationof activity (acceleration of handwriting, time limit, etc.)are not entirely adequate to the functional capacities ofsix- to seven-year-old children [11].

Handwriting disturbances or difficulties in thecourse of skill development are estimated by substan-tially different criteria in research (psychophysiologicalstudies) and in pedagogical practice. In addition, thecriteria of efficient learning and, hence, the principlesof identifying the difficulties are not standardized inRussia as they are in many other countries [10, 16], andevery teacher uses subjective estimates, mainly in theterms good/bad handwriting. Teachers partly or entirelyignore the psychophysiological mechanisms of the for-mation of the motor skill and stages of its development,each of which has its own specific characteristics oftemporal and qualitative organization of movement.Forced acceleration of handwriting is one of the leadingfactors that impede the formation of the handwritingmotor skill during learning [6, 11].

The purpose of this study (which is part of an inte-grated program of neurophysiological and psychophys-iological studies on writing skill development) was toanalyze the temporal and qualitative structure of writ-ing movements in six- to seven-year-old right-handed(group I) and left-handed (group II) children and chil-dren with underdeveloped visuomotor coordination(group III).

METHODS

The characteristics of writing skill developmentwere analyzed using the model of writing the letter

O

(20–25 times) at a habitual pace, without focusing onthe handwriting quality.

Handwriting was used as a model of movementsbecause of the specificity of this activity, which entirelycorresponded to the goals and objectives of the study.First, these movements are formed only in the course oflearning, so the process was easy to analyze. Second,writing is a complex motor activity related to multimo-dal activities of almost all cortical structures. Third,

writing permits an objective estimation of the qualita-tive and temporal parameters of the activity reflectingthe processes involved in the organization and controlof voluntary activity.

To record the mechanogram of writing movements,a strain gauge was attached to the tip of a ballpoint pen;the signal from the strain gauge was transmitted,through a system of amplifiers, to a recorder, whichmade it possible to obtain objective characteristics ofthe temporal structure of movements [28]. The tempo-ral structure of movements is a highly informativeparameter of the organization of integrated movementand its individual components, reflecting the activitiesof higher regulatory mechanisms [29–33].

A recorded mechanogram was a curve schemati-cally shown in the figure. The following parameterswere determined from the mechanogram: the durationof movement, including the duration of each motor actin the series (

T

m

) and the duration of the pause (

T

p

); themovement-to-pause duration ratio (

T

m

/

T

p

); and the vari-ations of these parameters. The movement performancewas estimated by the following parameters of handwrit-ing quality: the stability of the heights and lengths ofindividual letters (measured by the height and lengthvariation coefficients) and the percentage of letters withdisturbed configuration (on the basis of expert assess-ment).

The parameters of the temporal structure and qualityof handwriting at the initial stage of writing skill devel-opment were analyzed in three groups of subjects agedsix to seven years: right-handed children (

N

= 19;group I), left-handed children (

N

= 17; group II), andchildren with underdeveloped visuomotor coordination(

N

= 19; group III). Most left-handed children involvedin the study had familial left-handedness and had nosignificant deviations of pre- and perinatal develop-ment. No attempts had been made to change the later-ality type during their individual development.

It is known that integration of afferent flows, mainlyvisuomotor integration, the mechanisms of which aredeveloped both with age and in the course of the devel-opment of movements, is very important at the initialstage of movement formation.

It is assumed that visual information makes it possi-ble to “calibrate” hand proprioception and helps toestablish the relationship of writing as a whole with theenvironment during writing (and other graphic activi-ties) by determining the positions of the body and handand participating in the information support of posture[34].

Visuomotor coordination deficit, which is easy todiagnose in children at the age studied [35], is found in25–30% of schoolchildren [36] and causes markedlearning difficulties under real conditions [6, 11, 36]. Todetermine the degree of development of visuomotorcoordination, I used the method of estimation of visualperception development described earlier [37].

T

p

T

m

O O

T

m

Scheme of the movement mechanograms of children writ-ing a series of letters

O

. Designations:

T

m

, duration ofmovement (writing the letter

O

);

T

p

, duration of the pausebetween movements in the series.

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PSYCHOPHYSIOLOGICAL MECHANISMS OF WRITING DIFFICULTIES 541

RESULTS AND DISCUSSION

The temporal and qualitative parameters of the orga-nization of voluntary movements in all groups of six- toseven-year-old children studied (table) unambiguouslyindicated that neuromuscular regulation was imperfect,and an adequate task of the movement was underdevel-oped. It should be remembered that time was not lim-ited and attention was not focused on handwriting qual-ity, i.e., all subjects “chose” these parameters them-selves.

As can be seen from these data, handwriting at theinitial stage of skill development was characterized bya pause longer than the time of performing an individ-ual movement in the series. The pause is a necessarycomponent of multisensor synthesis in performing aseries of writing movements [28, 38]. It is regarded asthe so-called short-term memory pause, which servesfor estimating and perceiving the next movement, aswell as for a more efficient use of the visual control ofgraphic movements [39].

Such a long pause between individual movements inthe series, which fluctuated very little in each subject,emphasizes the underdevelopment of the movementtask and the program of its performance. The physio-logical role of the pause as a pause for perception andcurrent correction reflects the necessity and importanceof constant comparison, estimation, and correction inthe course of movement. Apparently, this determinesnot only its duration, which exceeds the duration of themovement itself, but also the considerable variation ofthis parameter. The pause is intended for eliminatingerrors under conditions of considerable internal andexternal “noise” characteristic of the initial stages ofmovement development. The pause allows a “quantumof movement” [31] to be analyzed and a new motor pro-gram (or, more precisely, a corrected one) to be devel-oped.

The longer duration of a pause compared to an indi-vidual movement in the series was common for theright-handed and left-handed six- to seven-year-oldchildren (groups I and II). The ratio

T

p

/

T

m

was 1.08

±

0.14 in group I and considerably higher (1.53

±

0.09) ingroup II; i.e., the pause was one and a half times longerthan the movement in the left-handed children. This isa substantial difference characterizing the considerablecomplexity of movement performance. Together with alarger percentage of disturbances in the configurationof graphic elements and a more pronounced tremor, thisfinding indicated that the movements were more diffi-cult for the left-handed children.

The fact that speed was the main “task” in the left-handed children is equally important. The speed waseven higher than in the right-handed children of thesame age; however, this problem remained unsolvable,because it was inadequate to the functional capacity ofthe children. The duration of the pause emphasizes thiscontradiction, indicating that the choice of the motortask was inefficient and underdeveloped. Probably, the“noise” during movement performance increased in theleft-handed children because of the organizationalspecificity of the functional movement control system(the brain structures are more autonomic, and theirinteraction is less intense). This led to an increase in theduration of the pause, because the perception of move-ment strategy and the choice of adequate and signifi-cant conditions, performance estimation criteria, etc.,were complicated. Apparently, the long pause indicatedthat the movement program had to be analyzed anewbefore every movement in the series, and the activityhad to be corrected in the process, which accounted forthe low efficiency of the temporal organization ofmovements.

The inefficiency of movement organization and con-trol during writing in both right-handed and left-handedchildren at the initial stage of skill development wasevidenced by a considerable variation of the height andlength of letters (configuration instability), disturbedconfiguration, and pronounced tremor (table). In thechildren from group II, the variations of the height andlength of graphic elements (55.61 and 56.21%, respec-tively) were practically the same as in the children fromgroup I (52.36 and 60.10%, respectively); however, thefrequency of configuration disturbances was signifi-

Temporal and qualitative parameters of writing at the initial stage of the skill development (six to seven years of age)

Temporal and qualitativeparameters

Group I Group II Group III

M

±

m V M

±

m V M

±

m V

T

m

, s 3.22

±

0.30 42.86 2.71

±

0.20 27.68 4.64

±

0.34 30.19

T

p

, s 3.49

±

0.30 39.54 4.14

±

0.27 24.46 6.63

±

0.42 26.10

T

p

/

T

m

1.08

±

0.14 59.63 1.53

±

0.09 22.06 1.43

±

0.07 20.17

Letter height, mm 11.42

±

1.30 52.36 12.34

±

1.83 55.61 9.23

±

1.19 53.12

Letter length, mm 8.19

±

1.07 60.10 10.14

±

1.52 56.21 7.64

±

1.03 55.54

Configuration disturbances, % 51.20

±

2.03 – 83.6

±

3.18 – 65.3

±

1.92 –

Degree of tremor, % 23.20

±

1.27 – 44.20

±

2.11 – 69.2

±

2.40 –

Additional strokes, % – – – – 64.8

±

1.56 –

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cantly (

P

< 0.05) higher (83.6%); the level of tremorwas almost two times higher (44.2 versus 23.2%).

Note that the visuomotor coordination deficit deter-mined the specificity of movement organization duringwriting (table). The analysis of movement performanceshowed that movements in the children from group IIIwere as unstable as in the children from group I; thevariation of the height and length of letters, character-izing the stability of movement trajectory, were large.The parameters of configuration disturbance (i.e., dis-turbance of the movement trajectory) were equally high(65.3%). Apparently, this was accounted for not only byage-related specificity of movement organization butalso by the characteristics of the initial stage of motorskill development. The low efficiency (low quality orpoor performance) of movements and high instabilityof graphic forms in the children from group III wereaccounted for by the fact that, at the initial stage ofmovement development, the motor task could not besuccessfully solved, because the necessary system ofmovement control was imperfect (underdeveloped).The necessity to “block” excessive degrees of freedomof the biocinematic chain inevitably leads to movementenslaving and high instability and strain. Considerabletremor (69.2%) indicated a higher strain of movementperformance in group III.

Probably, such complex and finely coordinatedmovements are practically impossible at the given stageof individual development, when the body is neithermorphologically nor functionally ready for their perfor-mance (the nervous control of movement is imperfect;the small muscles of the hand, as well as the bones ofthe carpus and finger phalanges, have not been com-pletely developed; and the endurance of static load islow). Additional difficulties related to the underdevel-opment of visuomotor coordination cannot consider-ably impair the performance of already inefficientmovements, but they increase the strain.

However, the analysis of the temporal parameters ofmovements makes it possible to detect the link ofmovement organization where the visuomotor coordi-nation deficit is sufficiently distinct. First of all, notethat both individual movements and pauses were signif-icantly longer in the children from group III than in thechildren from group I (

4.64

±

0.34

versus

3.22

±

0.30

,

P

< 0.05, and 6.63

±

0.42 versus 3.44

±

0.30,

P

< 0.01,respectively). Apparently, the slower movement and theconsiderably longer pause between individual move-ments in the series allowed the children to compensatefor the visuomotor coordination deficit, at least partly,by estimating and correcting movements in the courseof motor activity. This suggestion is confirmed by alarge proportion (64.8%) of additional strokes, whichthe children from group I made rarely, if at all. Addi-tional stokes along the movement trajectory indicatedthat the trajectory was corrected in the process, whichobviously considerably slowed down the movement.

The longer pause as an element of multisensor syn-thesis underlying the correction performed in thecourse of movement indicates that, if visuomotor inte-gration is underdeveloped, then the analysis and correc-tion of the movements already performed and the pro-gramming of the next movement take up more time.

Thus, the fulfillment of a specific motor task mayinvolve different mechanisms of current control at dif-ferent levels of the development of functions that arenecessary for the given activity. Verbal estimation andverbal control are very important, which is evidencedby the objective recording of the children verbalizingtheir estimation/correction, such as “Oh no,

…

notthere, like this

…

,” “I have written this wrong

…

,” etc.This indicates that the visuomotor coordination deficitis partly compensated for by attention to the organiza-tion of movements, which allows the children to writeas correctly as possible but considerably alters the tem-poral parameters of the movement, i.e., actuallychanges the programming of movement sequence. Inthis case, the visuomotor coordination deficit serves asa component of the informational complication of themotor task that increases the time intervals of move-ment organization.

CONCLUSIONS

The results of this study indicate that the temporaland qualitative organization of movements during writ-ing at the initial stages of the skill development reflectschanges in the essence and conditions of the motor taskin all children of the given age.

As the writing speed is formed at the initial stages oflearning, the disturbance of the temporal structure ofmovements negatively affects the temporal organiza-tion of movements, drastically decreases the quality,and impedes the development of the skill. In left-handed children and, especially, children with underde-veloped visuomotor coordination, destructive pro-cesses accompanying accelerated writing are evenmore pronounced.

The difficulties with learning and formation ofgraphic movements, observed in the case of visuomotorcoordination deficit, may have been related not only tothe imprecise program of activity and the absence ofinternal conditions necessary for establishing a specificprogram, but also to the absence of appropriate externalconditions.

At the initial stage of movement development, chil-dren cannot yet choose a specific motor task or developa program of subsequent activity under conditions of aminimum number of necessary external stimuli. Theinitial stage of movement development is characterizedby a predominance of environmental conditions; if theydo not correspond to a child’s capacities, difficultieswith skill development are inevitable. Another charac-teristic of movement performance at the initial stage oflearning is the underdevelopment of an integrated pro-

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gram of successive movements in the series, whichincreases the importance of the pause between individ-ual movements necessary for current correction.

Under test conditions, in the absence of restrictionswith respect to time and speed, quality criteria were notused. In the situation when movement performance isdifficult, the underdevelopment of visuomotor coordi-nation was compensated for by changes in the temporalstructure of movements, an increase in the pause dura-tion, and enhancement of the current control and cor-rection. This means that the body has a compensationcapacity in the absence of substantial disturbances offunctional development; however, this capacity ishardly used at school. Under the actual conditions oflearning, speed is a dominant goal, and the time givenfor writing exercises is always limited; i.e., there are noconditions for triggering the compensatory mecha-nisms. In addition, prematurely aiming at speed isfraught with serious danger. Under these conditions,actions follow the scheme of reactions suppressing cog-nitive and estimating components [32]; therefore, cur-rent correction and “tuning” of the program are impos-sible.

It is conceivable that the appearance and growth ofwriting difficulties in schoolchildren largely result froman insufficient account of the psychophysiologicalmechanisms of the formation of this skill and the incon-sistency between the elementary school requirementsand the functional capacities of children.

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