Journal of Oral Rehabilitation, 1975, Volume 1, pages 63-73
Oral ability to recognize forms and oral motor ability in 11-year-old children*
HORST L A N D T and B E N G T I N G E R V A L L Departments of Prosthetie Dentistry and Orthodontics, Faculty of Odontology, University of Gothenburg Summary
Oral ability to recognize forms and oral motor ability were examined in twenty children, aged 11 years, with normal occlusion. In the RF-test (recognition of form) the children identified the test pieces quicker but with a higher frequency of misidentification of the test pieces than a group of 17-year-old boys studied earlier. The effect of learning on the children was substantial with much quicker and greater certainty from one examination to another. Identification time and misidentification were positively correlated (individuals with long identification time also had a high frequency of errors). In the MA-test (oral motor ability) the children required a longer time to assemble the halves of the test pieces than did 17-year-old boys. A considerable effect of learning was found also in the MA-test. The results of the RF-test and the MA-test varied independently of each other for which reason the two tests measure different components of oral ability. Introduction
In some types of malocclusion, for example frontal open-bite, an atypical behaviour of the tongue during swallowing may be seen. In swallowing with tongue-thrust the tongue protrudes between the upper and lower front teeth during the act of swallowing. Attention to this particular type of swallowing was drawn by Rix (1946) who considered it to be the cause of malocclusion. Swallowing with tongue-thrust may, however, also be looked upon as an adaptation to an existing malocclusion (Hovell, 1962; Cleall, 1965) and may therefore disappear if the malocclusion is corrected. Though excercises to correct an atypical swallowing pattern have been recommended (Straub, 1962) the policy of most orthodontists is in fact to treat the malocclusion and in most cases the treatment result will be stable. In some cases, however, a relapse will occur probably because of a persistent unfavourable swallowing pattern. To avoid misfortunes in treatment there is consequently a great need of methods to diagnose the character of the muscular pattern in order to discover those cases where the pattern is not likely to normalize with treatment of the malocclusion. Tests of oral ability to recognize form and oral motor ability may reveal differences in * Report No. 18/1974 Department of Prosthetic Dentistry, University of Gothenburg. Correspondence: Dr H. Landt, Faculty of Odontology, University of Gothenburg, Fack, 400 33 Gothenburg 33, Sweden.
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Oral recognition and motor ability in ehildren
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muscular pattern that may be of value for the prognosis of the possibility of obtaining a change of the muscular pattern. In children, however, the oral ability to recognize forms (RF-test) has been studied mainly by comparing the oral tactile ability in individuals with normal and impaired speech (for survey see Landt, 1974a). The oral motor ability in children has apparently been the subject of only one investigation (Seminarial study, Umea, 1966). The knowledge of children's oral abihty to recognize forms, and especially of the oral motor ability, is thus meagre. The present investigation was undertaken to increase this knowledge. Its purpose was— (a) to find out whether a series of test bodies found suitable for the RF-test in adolescents is suitable also in the investigation of children; (b) to assess the oral ability to recognize forms and the oral motor ability in children and to study these two abilities for any correlation; (c) to study the learning effect in children in the RF-test and in the oral motor ability test (MA-test). The results were compared with those in a corresponding investigation in 17-yearold boys (Landt, 1974c,d,f). Material The material consisted of ten boys and ten girls, in the 12th year of life (mean 11-7 years). In all ofthe children occlusion was normal and there were no signs of functional disorders of the masticatory system. The number of erupted permanent teeth was, on the average, 20-8 (range 12-28). Method RF-test The person tested was asked to try to identify twelve test bodies placed in the mouth one at a time Four grades of difficulty of identification of the test bodies were used (identification levels 0-3), each grade comprising three test bodies (Fig. 1). The test bodies and the experimental method have been described previously (Landt &Hedegard, 1974). MA-test The person undergoing the test was requested to assemble two halves of a test piece (Fig. 2). Four test pieces were used. The halves of test piece 1 could be fitted together in the largest number of ways and test piece 4 in only one way (Landt & Hedegird, 1974). The examiner had been trained and tested according to earlier described principles (Landt, Ahlin & Lindquist, 1974). In the RF-test the person undergoing the examination was informed immediately of the result of each trial. This is of certain importance for assessing the effect of training on the results of the tests (Landt, 1974g). The RF-test as well as the MA-test was carried out in triplicate on each individual on three different trial-rounds (all together nine RF-tests and nine MA-tests on each child). The trial-rounds were carried out on different days at intervals of one or more commonly, several days between the occasions. Differences between means were tested with the /-test and correlations between variables were estimated by calculation of product moment correlation.
66
Horst Landt and Bengt Ingervall
Fig. 2. Test pieces for MA-test.
Results (1) Ability to recognize forms (RF-test) The identification times for the test pieces in the RF-test are given in Table 1. The order of the average identification times was that expected, i.e. those test bodies easiest to recognize (level 0) were identified quickest, and those most difficult to identify (level 3), slowest. There was a considerable inter-individual variation, the identification time for some children being up to seven times that for others. Table 1. RF-test, identification times (in seconds) for levels of difficulty at nine tests in children and three in 17-year-old boys Children (n = 20) Level of difficulty 0 1 2 3 All levels pooled
M±:eM
Range
7-25±O -88 n-48±i -06
2-41-17-15 3-37-21-18 6-74-27-74 4-67-27-85
15-28±1 -27 16-23±1 -50 12-50±l -12
17-year-old bovs (n — 10) M 6-53 16-77 23-27 25-17 17-93
= Standard error of the mean.)
Table 1 gives also the average identification times of 17-year-old boys (Landt, 1974c). In these boys only one trial-set was performed on each trial-round (all together three RF-trial-sets) for which reason training was less than in the children examined
Oral reeognition and motor ability in ehildren
67
Table 2. RF-test, frequency of misidentification for levels of difficulty at nine tests in children and three in 17-year-old boys
Level of difficulty 0 1 2 3 All levels pooled
Children (n = 20)
17-year-old boys (rt - 10)
M±eM(%)
Range (%)
M(%)
4-07±l-34 8-88±l-53 2O-37±2-68 32-59±3-4O 16-48±I-63
0-0-22-22 0-0-22-22 0-0-40-74 0-0-66-66
0-00 2-00 15-70 28-70 11-60
here. With the exception of test bodies with a level of difficulty of 0 the identification times were shorter for the children than for the 17-year-old boys. Erroneous identification. (Confusion of test pieces). The results were those expected with a higher frequency of errors with increasing level of difficulty of recognition ofthe test pieces (Table 2). Table 2 further shows that when using level 3 test pieces some children never made an error, while others frequently made misidentifications, which underlines the wide interindividual variation in ability to recognize forms. Though the children underwent a larger number of tests and thereby had more training than the 17-year-old boys, the children misidentified test pieces of all levels more often than the boys (Table 2). Ejfect of learning on RE-test can be expected to be reflected as decreasing identification time and lower frequency of misidentifications in repeated tests. That the effect of learning in children was considerable is apparent from Tables 3 and 4, which show that the average identification time and the frequency of misidentifications were lower on the second and third trial-round of the test than on the first. The difference in identification time between the first and the third trial-rounds was significant (/»< 0-001). Also the decrease in frequency of misidentifications between the first and third trial-round (about 60 %) was significant (P< 0-001). The average intraindividual reduction in identification time between the first and the third trial-rounds was 37 ± 4 % of the identification time on the first trial-round. All children except one showed a reduction in the identification time between the above mentioned trial rounds. The identification time for correct identification on the third trial-round was 53 ± 4 % of that on the first. Correlation between identification time and misidentification is given in Table 5. Only positive correlation coefficients were found between identification time and Table 3. RF-test, identification times (in seconds) on different occasions in children {n = 10). Levels of difficulty pooled Trial-round
M ± eM
Range
1 2 3
16-69±l-80 11-23 ±1-08 9-75±0-89
5-55-40-66 4-08-21-89 3-47-18-22
M
Horst Landt and Bengt Ingervall
Table 4. RF-test, frequency of misidentification on different occasions in children (n = 20). Levels of difficulty pooled Trial-round
M±eM(%)
Range (%)
1 2 3
24-44±2-22 ]5-69±l-85 9-31±l-59
8-33-47-22 0-00-27-77 0-00-25-00
Table 5. RF-test, correlation coefficients between identification time and number of misidentifications at the different levels of difficulty {n = 20) Identification time Level of difficulty 0 1 2 3 All levels pooled
0
1
2
3
All levels pooled
0-75 0-24 0-08 0-50 0-51
0-58 0-43 0-26 0-44 0-56
0-74 0-13 0-12 0-45 0-47
0-60 0-20 0-18 0-41 0-46
0 - 69 0 - 25 0-17 0-47 0-52
Number of misidentification
misidentification. The correlation coefficients were statistically significant only for the use of the test pieces that were easiest to recognize (level 0). For all levels pooled the correlation coefficient between identification time and misidentification was 0-52. The corresponding correlation coefficient for the 17-year-old boys was 0-54 (Landt, 1974d). As in the 17-year-old boys (Landt, 1974d) positive correlations were found between the time necessary for identification of the test pieces of different degrees of difficulty (Table 6). The correlation coefficients in Table 6, all of which were significant (P< 0-001), show that children with a long identification time for the test pieces of a given level of difficulty also had long identification times for the test pieces of other levels. Also the frequencies of misidentifications at different levels were positively correlated (Table 7). Children with a high frequency of errors at a certain level of difficulty thus tended to have a high frequency of error also at other levels. (2) Oral motor ability {MA-test) The times necessary for assembling the test pieces are given in Table 8. As expected, the assembly times were shortest for test piece 1 with the largest number of possible ways in which the halves could be fitted together, and longest for test piece 4, which could Table 6. RF-test, correlation coefficients between identification times at different levels of difficulty (« = 20) Level of difficulty 0 1 2 3
1
2
3
0-83
0-88 0-87
0-80 0-93 0-93
AH levels pooled 0-91 0-95 0-97 0-97
Oral recognition and motor ability in children
69
Table 7. RF-test, correlation coefficients between number of misidentifications at the different levels of difficulty (« = 20) Level of difficulty
1
0 1 2 3
0-18
2
3 0- 12 0- 38
0 -20 0 -30 0 -55
All levels pooled 0 -40 0 -58 0 -81 0 -86
Table 8. MA-test, assembly times (in seconds) of test pieces in nine tests in children and in 17-year-old boys Children (n = 20) Test piece
M±eM
1 2 3 4 All test pieces pooled
16-51±2-87 32-09±4-22 52-85±4-87 87-68±6-65 47-28±4-19
17-year-oId boys {n - 10) Range M
6-22- 64-55 9-77- 83-33 23-11-138-55 47-33-146-11
14-3 15-6 33-1 42-6 26-4
be fitted together in only one way. The inter-individual variation was considerable, the longest time being tenfold that of the shortest (test piece 1). The average assembly times noted for all test pieces were longer than for the 17year-old boys (Table 8). The difference was smallest for the easiest test piece (1). The effect of learning on the MA-test is given in Table 9. The average times decreased with increasing number of trial-rounds. The difference between trial-round 1 and 3 was highly significant (/•
Oral ability to recognize forms and oral motor ability in 11-year-old children*
HORST L A N D T and B E N G T I N G E R V A L L Departments of Prosthetie Dentistry and Orthodontics, Faculty of Odontology, University of Gothenburg Summary
Oral ability to recognize forms and oral motor ability were examined in twenty children, aged 11 years, with normal occlusion. In the RF-test (recognition of form) the children identified the test pieces quicker but with a higher frequency of misidentification of the test pieces than a group of 17-year-old boys studied earlier. The effect of learning on the children was substantial with much quicker and greater certainty from one examination to another. Identification time and misidentification were positively correlated (individuals with long identification time also had a high frequency of errors). In the MA-test (oral motor ability) the children required a longer time to assemble the halves of the test pieces than did 17-year-old boys. A considerable effect of learning was found also in the MA-test. The results of the RF-test and the MA-test varied independently of each other for which reason the two tests measure different components of oral ability. Introduction
In some types of malocclusion, for example frontal open-bite, an atypical behaviour of the tongue during swallowing may be seen. In swallowing with tongue-thrust the tongue protrudes between the upper and lower front teeth during the act of swallowing. Attention to this particular type of swallowing was drawn by Rix (1946) who considered it to be the cause of malocclusion. Swallowing with tongue-thrust may, however, also be looked upon as an adaptation to an existing malocclusion (Hovell, 1962; Cleall, 1965) and may therefore disappear if the malocclusion is corrected. Though excercises to correct an atypical swallowing pattern have been recommended (Straub, 1962) the policy of most orthodontists is in fact to treat the malocclusion and in most cases the treatment result will be stable. In some cases, however, a relapse will occur probably because of a persistent unfavourable swallowing pattern. To avoid misfortunes in treatment there is consequently a great need of methods to diagnose the character of the muscular pattern in order to discover those cases where the pattern is not likely to normalize with treatment of the malocclusion. Tests of oral ability to recognize form and oral motor ability may reveal differences in * Report No. 18/1974 Department of Prosthetic Dentistry, University of Gothenburg. Correspondence: Dr H. Landt, Faculty of Odontology, University of Gothenburg, Fack, 400 33 Gothenburg 33, Sweden.
OJ
V
o
I O
a
CD
Oral recognition and motor ability in ehildren
65
muscular pattern that may be of value for the prognosis of the possibility of obtaining a change of the muscular pattern. In children, however, the oral ability to recognize forms (RF-test) has been studied mainly by comparing the oral tactile ability in individuals with normal and impaired speech (for survey see Landt, 1974a). The oral motor ability in children has apparently been the subject of only one investigation (Seminarial study, Umea, 1966). The knowledge of children's oral abihty to recognize forms, and especially of the oral motor ability, is thus meagre. The present investigation was undertaken to increase this knowledge. Its purpose was— (a) to find out whether a series of test bodies found suitable for the RF-test in adolescents is suitable also in the investigation of children; (b) to assess the oral ability to recognize forms and the oral motor ability in children and to study these two abilities for any correlation; (c) to study the learning effect in children in the RF-test and in the oral motor ability test (MA-test). The results were compared with those in a corresponding investigation in 17-yearold boys (Landt, 1974c,d,f). Material The material consisted of ten boys and ten girls, in the 12th year of life (mean 11-7 years). In all ofthe children occlusion was normal and there were no signs of functional disorders of the masticatory system. The number of erupted permanent teeth was, on the average, 20-8 (range 12-28). Method RF-test The person tested was asked to try to identify twelve test bodies placed in the mouth one at a time Four grades of difficulty of identification of the test bodies were used (identification levels 0-3), each grade comprising three test bodies (Fig. 1). The test bodies and the experimental method have been described previously (Landt &Hedegard, 1974). MA-test The person undergoing the test was requested to assemble two halves of a test piece (Fig. 2). Four test pieces were used. The halves of test piece 1 could be fitted together in the largest number of ways and test piece 4 in only one way (Landt & Hedegird, 1974). The examiner had been trained and tested according to earlier described principles (Landt, Ahlin & Lindquist, 1974). In the RF-test the person undergoing the examination was informed immediately of the result of each trial. This is of certain importance for assessing the effect of training on the results of the tests (Landt, 1974g). The RF-test as well as the MA-test was carried out in triplicate on each individual on three different trial-rounds (all together nine RF-tests and nine MA-tests on each child). The trial-rounds were carried out on different days at intervals of one or more commonly, several days between the occasions. Differences between means were tested with the /-test and correlations between variables were estimated by calculation of product moment correlation.
66
Horst Landt and Bengt Ingervall
Fig. 2. Test pieces for MA-test.
Results (1) Ability to recognize forms (RF-test) The identification times for the test pieces in the RF-test are given in Table 1. The order of the average identification times was that expected, i.e. those test bodies easiest to recognize (level 0) were identified quickest, and those most difficult to identify (level 3), slowest. There was a considerable inter-individual variation, the identification time for some children being up to seven times that for others. Table 1. RF-test, identification times (in seconds) for levels of difficulty at nine tests in children and three in 17-year-old boys Children (n = 20) Level of difficulty 0 1 2 3 All levels pooled
M±:eM
Range
7-25±O -88 n-48±i -06
2-41-17-15 3-37-21-18 6-74-27-74 4-67-27-85
15-28±1 -27 16-23±1 -50 12-50±l -12
17-year-old bovs (n — 10) M 6-53 16-77 23-27 25-17 17-93
= Standard error of the mean.)
Table 1 gives also the average identification times of 17-year-old boys (Landt, 1974c). In these boys only one trial-set was performed on each trial-round (all together three RF-trial-sets) for which reason training was less than in the children examined
Oral reeognition and motor ability in ehildren
67
Table 2. RF-test, frequency of misidentification for levels of difficulty at nine tests in children and three in 17-year-old boys
Level of difficulty 0 1 2 3 All levels pooled
Children (n = 20)
17-year-old boys (rt - 10)
M±eM(%)
Range (%)
M(%)
4-07±l-34 8-88±l-53 2O-37±2-68 32-59±3-4O 16-48±I-63
0-0-22-22 0-0-22-22 0-0-40-74 0-0-66-66
0-00 2-00 15-70 28-70 11-60
here. With the exception of test bodies with a level of difficulty of 0 the identification times were shorter for the children than for the 17-year-old boys. Erroneous identification. (Confusion of test pieces). The results were those expected with a higher frequency of errors with increasing level of difficulty of recognition ofthe test pieces (Table 2). Table 2 further shows that when using level 3 test pieces some children never made an error, while others frequently made misidentifications, which underlines the wide interindividual variation in ability to recognize forms. Though the children underwent a larger number of tests and thereby had more training than the 17-year-old boys, the children misidentified test pieces of all levels more often than the boys (Table 2). Ejfect of learning on RE-test can be expected to be reflected as decreasing identification time and lower frequency of misidentifications in repeated tests. That the effect of learning in children was considerable is apparent from Tables 3 and 4, which show that the average identification time and the frequency of misidentifications were lower on the second and third trial-round of the test than on the first. The difference in identification time between the first and the third trial-rounds was significant (/»< 0-001). Also the decrease in frequency of misidentifications between the first and third trial-round (about 60 %) was significant (P< 0-001). The average intraindividual reduction in identification time between the first and the third trial-rounds was 37 ± 4 % of the identification time on the first trial-round. All children except one showed a reduction in the identification time between the above mentioned trial rounds. The identification time for correct identification on the third trial-round was 53 ± 4 % of that on the first. Correlation between identification time and misidentification is given in Table 5. Only positive correlation coefficients were found between identification time and Table 3. RF-test, identification times (in seconds) on different occasions in children {n = 10). Levels of difficulty pooled Trial-round
M ± eM
Range
1 2 3
16-69±l-80 11-23 ±1-08 9-75±0-89
5-55-40-66 4-08-21-89 3-47-18-22
M
Horst Landt and Bengt Ingervall
Table 4. RF-test, frequency of misidentification on different occasions in children (n = 20). Levels of difficulty pooled Trial-round
M±eM(%)
Range (%)
1 2 3
24-44±2-22 ]5-69±l-85 9-31±l-59
8-33-47-22 0-00-27-77 0-00-25-00
Table 5. RF-test, correlation coefficients between identification time and number of misidentifications at the different levels of difficulty {n = 20) Identification time Level of difficulty 0 1 2 3 All levels pooled
0
1
2
3
All levels pooled
0-75 0-24 0-08 0-50 0-51
0-58 0-43 0-26 0-44 0-56
0-74 0-13 0-12 0-45 0-47
0-60 0-20 0-18 0-41 0-46
0 - 69 0 - 25 0-17 0-47 0-52
Number of misidentification
misidentification. The correlation coefficients were statistically significant only for the use of the test pieces that were easiest to recognize (level 0). For all levels pooled the correlation coefficient between identification time and misidentification was 0-52. The corresponding correlation coefficient for the 17-year-old boys was 0-54 (Landt, 1974d). As in the 17-year-old boys (Landt, 1974d) positive correlations were found between the time necessary for identification of the test pieces of different degrees of difficulty (Table 6). The correlation coefficients in Table 6, all of which were significant (P< 0-001), show that children with a long identification time for the test pieces of a given level of difficulty also had long identification times for the test pieces of other levels. Also the frequencies of misidentifications at different levels were positively correlated (Table 7). Children with a high frequency of errors at a certain level of difficulty thus tended to have a high frequency of error also at other levels. (2) Oral motor ability {MA-test) The times necessary for assembling the test pieces are given in Table 8. As expected, the assembly times were shortest for test piece 1 with the largest number of possible ways in which the halves could be fitted together, and longest for test piece 4, which could Table 6. RF-test, correlation coefficients between identification times at different levels of difficulty (« = 20) Level of difficulty 0 1 2 3
1
2
3
0-83
0-88 0-87
0-80 0-93 0-93
AH levels pooled 0-91 0-95 0-97 0-97
Oral recognition and motor ability in children
69
Table 7. RF-test, correlation coefficients between number of misidentifications at the different levels of difficulty (« = 20) Level of difficulty
1
0 1 2 3
0-18
2
3 0- 12 0- 38
0 -20 0 -30 0 -55
All levels pooled 0 -40 0 -58 0 -81 0 -86
Table 8. MA-test, assembly times (in seconds) of test pieces in nine tests in children and in 17-year-old boys Children (n = 20) Test piece
M±eM
1 2 3 4 All test pieces pooled
16-51±2-87 32-09±4-22 52-85±4-87 87-68±6-65 47-28±4-19
17-year-oId boys {n - 10) Range M
6-22- 64-55 9-77- 83-33 23-11-138-55 47-33-146-11
14-3 15-6 33-1 42-6 26-4
be fitted together in only one way. The inter-individual variation was considerable, the longest time being tenfold that of the shortest (test piece 1). The average assembly times noted for all test pieces were longer than for the 17year-old boys (Table 8). The difference was smallest for the easiest test piece (1). The effect of learning on the MA-test is given in Table 9. The average times decreased with increasing number of trial-rounds. The difference between trial-round 1 and 3 was highly significant (/•
