NeuroRehabilitation ELSEVIER
NeuroRehabilitation 10 (1998) 75-82
Sequencing deficits in subjects with developmental dyspraxia and adult onset apraxia Janet L. Poole Departments of Orthopaedics and Family and Community Medicine, Occupational Therapy Program, Room 215, University of New Mexico Health Sciences and Services Building, Albuquerque, NM 87131-5641, USA
Abstract
Objective: The purpose of this study was to examine and compare the performance of children with developmental dyspraxia and adults with apraxia to learn and retain two sequencing tasks. Study design: Three groups of subjects with dyspraxia and apraxia (children and young adults with both dyspraxia and learning disabilities and older adults with apraxia and left hemisphere strokes) and three groups of age-matched control subjects learned one-handed shoe tying and a hand sequence task. Retention was assessed after a 5-min delay. Performance was scored as the number of trials needed to perform each task and the types of errors that were made. Results: For both the tasks, the control groups performed better than the groups with dyspraxia/apraxia and performance during the retention trials was better than performance during the learning trials. On the hand sequence task, the children and young adult groups performed better than the older adult groups. Conclusions: Subjects with dyspraxia and apraxia have difficulty with similar sequencing tasks. However, the poorer performance by the older adult group with apraxia suggests that the underlying mechanisms for sequencing may be different for apraxia than for dyspraxia. © 1998 Elsevier Science Ireland Ltd. Keywords: Apraxia; Developmental dyspraxia; Motor learning; Stroke; Learning disabilities
1. Introduction Apraxia is a disorder in performing skilled movements that cannot be attributed to sensory loss, weakness, or cognitive or perceptual impairments. Apraxia frequently accompanies brain damage to the left hemisphere as from a stroke, head injury, or brain tumor. A similar developmental disorder in children, referred to as devel-
opmental dyspraxia, is also a disorder in conceptualizing and executing skilled movements. However, developmental dyspraxia is not usually associated with a brain lesion but is considered a disorder in sensory integration and is often seen in individuals with learning disabilities. It is not clear whether dyspraxia persists into adulthood. Individuals with apraxia and developmental dyspraxia have been observed to have sequencing
1053-8135/98/$19.00 © 1998 Elsevier Science Ireland Ltd. All rights reserved. PlI S1053-8135(97)00047-4
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J.L. Poole / NeuroRehabilitation 10 (1998) 75-82
deficits [1-5]. The majority of the studies have examined hand posture sequencing [4-7] while a few others have looked at grasping, pushing, or moving knobs, buttons or bars in a sequence [1-3,8]. In general, sequencing deficits are observed more with adult subjects with left hemisphere brain damage than with right hemisphere brain damage. Indeed, studies also showed that subjects with left hemisphere damage with apraxia could not even perform or learn motor sequences [7,8]. This inability to learn motor sequences is of particular importance in individuals who have accompanying hemiplegia or hemiparesis as these individuals may need to learn new compensation methods and/or techniques for communication and performance of daily tasks. Children with developmental dyspraxia have been also found to have difficulty learning hand posture sequences [9] and sequences for pushing and pulling knobs [1,10]. Furthermore, children with additional language dysfunction had more difficulty recalling a movement sequence than children without language impairments [1,10]. The number of studies examining errors made on sequencing tasks is limited. On Kimura's [3] push, pull and press sequencing test, errors were recorded as unrelated (movements bore no resemblance to the task), perseverative, sequencing (movements were out of sequence), incomplete (wrong fingers were used or movements were not of sufficient strength to sound a buzzer) and holding (holding a position too long). Subjects with left hemisphere cerebral damage and aphasia were found to make perseverative movements unrelated to the task rather than sequencing or incomplete errors. In Roy's (1981) sequencing study [8] in which subjects moved knobs in different action patterns, errors were scored as position and order sequencing errors, perseveration errors and omissions of actions. Subjects with left hemisphere damage without aphasia and subjects with right hemisphere damage made simple sequencing errors and substituted similar actions whereas the subjects with left hemisphere damage and aphasia made more complex errors and made only a few related substitutions. When subjects were asked to produce a sequence from memory,
the subjects with left hemisphere damage made more errors than subjects with right hemisphere damage and the errors tended to be repetitive. In addition, the subjects with left hemisphere damage and aphasia made more unrelated substitutions and perseverative errors. Error analysis during performance of sequential movements has not been done in children except for informal observations which seem to indicate that children make perservative errors [10]. Yet, Roy [8] proposed that error analysis may provide insight into the behavioral processes involved in dyspraxia and apraxia. While the etiology of adult onset apraxia and developmental dyspraxia is clearly different, there is some data to suggest that individuals with apraxia and dyspraxia have difficulty with the same types of tasks [11]. However, the tasks used in previous studies were single movements and not movement sequences. The purpose of the present study was to examine and compare abilities of children and young adults with developmental dyspraxia and adults with apraxia to learn and retain two tasks: a functional meaningful task (one handed shoe-tying) and a meaningless task (hand sequence). A second purpose was to examine and compare errors made while performing the two sequence tasks. Age matched control groups were used to control for differences due to age. 2. Methods 2.1. Subjects
Six groups of subjects were included in this study: children with dyspraxia and learning disabilities, control children, young adults with dyspraxia and learning disabilities, control young adults, older adults with left hemisphere brain damage and apraxia and control older adults. Subject were selected based on convenience and age. Additional criteria for the dyspraxic / apraxic groups required subjects to score below the cut-off score for dyspraxia/apraxia on the De Renzi, Pieczuro and Vignolo Test of Apraxia [12,13] and have a full-scale Wechsler Intelligence Scale score
J.L. Poole / NeuroRehabilitation 10 (1998) 75-82
of at least 85. The age criterion was 9-11 years for children, 18-30 years for the young adults and 60-75 years for the older adults. Subjects in the group of children with dyspraxia had to score 19 or below on the children's version of the DeRenzi, Pieczuro and Vignolo Test of Apraxia [13] while the young adults with dyspraxia and older adults with apraxia had to receive a score of 17 or below on the adult version of the DeRenzi, Pieczuro and Vignolo Test of Apraxia [12]. Subjects in the control groups had to score above these cut-off scores. All groups had 10 subjects except for the young adult group with dyspraxia. Only eight subjects could be recruited who had dyspraxia and were in the predetermined age range and met the criteria described above. 2. 2. Children with dyspraxia
Subjects in this group ranged in age from 9.0 to 10.4 years (mean = 9.60), were suspected of being dyspraxic by an occupational therapist in a school setting and had a diagnosis of learning disability. On the Wechsler Intelligence Scale, their full scale scores ranged from 85 to 99 (mean = 89.1). There were five males and five females. 2.3. Control children
Subjects in this group consisted of non-dyspraxic children who were age-matched to the children with dyspraxia. The age range of this group was 9.2-10.4 years (mean = 9.73 years). These children had no known learning, behavioral, or neurological deficits as reported by their parents. There were four males and six females. 2.4. Dyspraxic learning disabled young adults
Subjects in this group were college students who were suspected of being dyspraxic by the director of the special services departments at the college and had a diagnosis of learning disability. They ranged in age from 18 to 28 years (mean = 21.70 years). On the Wechsler Intelligence Scale, their full scale scores ranged from 85 to 99 (mean = 90.6). There were four males and four females.
77
2.5. Control young adults
These subjects were age matched to the young adults with learning disabilities and dyspraxia. They ranged in age from 18.6 to 25.3 years (mean = 21.6 years). They reported no known learning, behavioral, or neurological deficits. There were five males and five females. 2.6. Apraxic left hemisphere brain damaged older adults
The subjects in this group consisted of subjects with left hemisphere damage from a stroke who were living at home who were suspected of having apraxia by a neuropsychologist and had vascular damage lateralized to the left hemisphere as ascertained by physicians' reports. They ranged in age from 60 to 75.1 years (mean = 68.7 years). There were six males and four females. The mean length of time since the stroke was 3 years, 10 months with a range from 1 year to 8 years, 2 months. 2. 7. Control older adults
These subjects were age matched to the subjects with stroke and ranged in age from 60.5 to 73.7 years (mean = 68.6 years). They had no known history of learning, behavioral, or neurological deficits as reported by the subject and/or family. There were five males and five females. The mean ages of the children in both the dyspraxia and control groups were similar as were the ages of the young adults in both the dyspraxia and control groups and the older adults in both the apraxia and control groups. In addition, the mean lOs of the children with dyspraxia and the young adults with dyspraxia were similar. 10 tests scores were not available for the older adults with left hemisphere brain damage and apraxia. 2.8. Tasks and procedures
Subjects were tested individually in a quiet room and performed the tasks with their preferred hand. Subjects were videotaped for the purpose of error analysis.
78
J.L. Poole / NeuroRehabilitation 10 (1998) 75-82
2.8.1. One-handed shoe tying The shoe was already laced in such a fashion that only one lace was available for tying. The task involved three basic steps: (1) putting the end of the lace through the top lace so that a loop remained; (2) inserting the thumb and index finger through the loop to pinch the rest of the lace; and (3) pulling on the lace to bring it though the loop to form a knot with one loop [14]. Subjects' scores for learning this task were the number of trials needed to perform the task correctly. The task was discontinued after five trials as a pilot study showed that subjects either learned the task on the fifth trial or became too frustrated to continue. Subjects unable to perform the task successfully in five trials were given a score of 7. To ascertain retention, subjects were asked to tie the shoe again after a delay of approximately 5 min. During the 5-min retention interval, subjects performed an apraxia screening test, the Luria sequence described below and gestures in response to verbal command and imitation [11]. The score again was the number of trials needed to tie the shoe correctly. The types of errors made on each trial were also recorded. The errors that could be made on the shoe tying tasks were sequencing, omission, perseveratioR, internal configuration and external configuration. An error was scored a sequencing error if the subject performed the sequence out of order, forgot a step, or forgot to insert the thumb and index finger through the loop to pinch the shoelace. A perseveration error was scored if the subject repeated the first step which consisted of putting the end of the shoelace back through the top lace or back through the loop. An error was scored as an internal configuration error if the subject's thumb and index finger kept moving to the end of the lace while pulling the lace through the loop to form a knot. In this instance, a knot was formed without a loop. The correct method consisted of keeping the thumb and index finger in one place on the lace while pinching the lace to pull it through the loop to make a knot with one loop. An external configuration error consisted of making the initial loop too big so that when the lace is pulled to form a knot, the
end of the lace comes back through the loop to form a knot without a loop. 2.8.2. Luria's hand sequence task This task consisted of three hand sequences: a fist, the palm flat and horizontal and the palm flat and vertical [15]. Subjects were tested with the preferred hand first and then the non-preferred hand. The score for each hand was the number of trials needed to perform the sequence 10 times in a row without any errors as per Motomura et al. [7]. If an error was made, the instructions were given again and the test repeated. The test was discontinued if subjects were unable to successfully complete the 10 sequences after five trials as a pilot study showed that subjects either learned the task on the fifth trial or became too frustrated to continue. Subjects unable to perform the task successfully in five trials were given a score of 7. A lower score meant less trials were needed, that is, better performance. To assess retention, subjects were asked to correctly perform the sequence 10 times in a row with each hand approximately 5 min later. During the 5-min retention interval, subjects performed gestures in response to verbal command and imitation and the shoe tying retention task. The score for the retention task was again, the number of trials needed to correctly perform the sequence 10 times in a row without any errors. In addition, the types of errors made on each trial were determined. Errors were scored as sequencing or perseveration. A sequencing error was made if the steps in the sequence were incorrect or steps were omitted, such as making a fist, palm of hand flat vertically, palm of hand flat horizontally and then a fist. A perseveration error was made if the subject repeated the previous step of part of the previous step, such as making a fist in the vertical position and then a fist in a horizontal position. 2.8.3. Reliability Before beginning the study, intrarater and interrater reliability were established for both tasks. To establish intrarater reliability, the author reviewed videotapes of 10 subjects two times, 1
J.L. Poole / NeuroRehabilitation 10 (1998) 75-82
79
Table 1 Mean number of trials for shoe tying learning and retention task for control and subjects with dyspraxia/apraxia Shoe learning
Control children Dyspraxia children Control young adults Dyspraxia young adults Control older adults Apraxia older adults
Shoe retention
n
Mean (No. Trials)
S.D.
Mean (No. Trials)
S.D.
10 10 10 8 10 10
1.8 4.9 1.0 6.0 1.5 4.1
1.3 2.0 0.0 2.1 0.7 2.3
1.3 2.6 1.0 3.1 1.0 2.6
0.48 2.0 0.0 2.3 0.0 1.8
week apart. Percent of agreement was 90% for the shoe tying task and 100% for the hand sequence task. To establish interrater reliability, an occupational therapist familiar with the scoring procedures reviewed videotapes of the same 10 subjects. Percent of agreement was 90% for both tasks.
trials was better than performance during the learning trials. The trial x diagnosis interaction (F j ,52 = 23.01, P < 0.0001) was also significant so although all groups performed better during retention, the groups with dyspraxia/apraxia improved more. Neither age nor any other interactions were significant.
3. Results
3.2. Learning/retention trials on Luria hand sequence
3.1. Learning/retention trials on the shoe tying task
Table 1 shows the mean scores for each group for the shoe tying tasks. Analysis of variance with repeated measures showed main effects for diagnosis (F j 52 = 56.08, P < 0.0001) and trial (F j 52 = 42.08, P 0.0001). Thus, the control groups 'performed better than the groups with dyspraxia/ apraxia and performance during the retention
NeuroRehabilitation 10 (1998) 75-82
Sequencing deficits in subjects with developmental dyspraxia and adult onset apraxia Janet L. Poole Departments of Orthopaedics and Family and Community Medicine, Occupational Therapy Program, Room 215, University of New Mexico Health Sciences and Services Building, Albuquerque, NM 87131-5641, USA
Abstract
Objective: The purpose of this study was to examine and compare the performance of children with developmental dyspraxia and adults with apraxia to learn and retain two sequencing tasks. Study design: Three groups of subjects with dyspraxia and apraxia (children and young adults with both dyspraxia and learning disabilities and older adults with apraxia and left hemisphere strokes) and three groups of age-matched control subjects learned one-handed shoe tying and a hand sequence task. Retention was assessed after a 5-min delay. Performance was scored as the number of trials needed to perform each task and the types of errors that were made. Results: For both the tasks, the control groups performed better than the groups with dyspraxia/apraxia and performance during the retention trials was better than performance during the learning trials. On the hand sequence task, the children and young adult groups performed better than the older adult groups. Conclusions: Subjects with dyspraxia and apraxia have difficulty with similar sequencing tasks. However, the poorer performance by the older adult group with apraxia suggests that the underlying mechanisms for sequencing may be different for apraxia than for dyspraxia. © 1998 Elsevier Science Ireland Ltd. Keywords: Apraxia; Developmental dyspraxia; Motor learning; Stroke; Learning disabilities
1. Introduction Apraxia is a disorder in performing skilled movements that cannot be attributed to sensory loss, weakness, or cognitive or perceptual impairments. Apraxia frequently accompanies brain damage to the left hemisphere as from a stroke, head injury, or brain tumor. A similar developmental disorder in children, referred to as devel-
opmental dyspraxia, is also a disorder in conceptualizing and executing skilled movements. However, developmental dyspraxia is not usually associated with a brain lesion but is considered a disorder in sensory integration and is often seen in individuals with learning disabilities. It is not clear whether dyspraxia persists into adulthood. Individuals with apraxia and developmental dyspraxia have been observed to have sequencing
1053-8135/98/$19.00 © 1998 Elsevier Science Ireland Ltd. All rights reserved. PlI S1053-8135(97)00047-4
76
J.L. Poole / NeuroRehabilitation 10 (1998) 75-82
deficits [1-5]. The majority of the studies have examined hand posture sequencing [4-7] while a few others have looked at grasping, pushing, or moving knobs, buttons or bars in a sequence [1-3,8]. In general, sequencing deficits are observed more with adult subjects with left hemisphere brain damage than with right hemisphere brain damage. Indeed, studies also showed that subjects with left hemisphere damage with apraxia could not even perform or learn motor sequences [7,8]. This inability to learn motor sequences is of particular importance in individuals who have accompanying hemiplegia or hemiparesis as these individuals may need to learn new compensation methods and/or techniques for communication and performance of daily tasks. Children with developmental dyspraxia have been also found to have difficulty learning hand posture sequences [9] and sequences for pushing and pulling knobs [1,10]. Furthermore, children with additional language dysfunction had more difficulty recalling a movement sequence than children without language impairments [1,10]. The number of studies examining errors made on sequencing tasks is limited. On Kimura's [3] push, pull and press sequencing test, errors were recorded as unrelated (movements bore no resemblance to the task), perseverative, sequencing (movements were out of sequence), incomplete (wrong fingers were used or movements were not of sufficient strength to sound a buzzer) and holding (holding a position too long). Subjects with left hemisphere cerebral damage and aphasia were found to make perseverative movements unrelated to the task rather than sequencing or incomplete errors. In Roy's (1981) sequencing study [8] in which subjects moved knobs in different action patterns, errors were scored as position and order sequencing errors, perseveration errors and omissions of actions. Subjects with left hemisphere damage without aphasia and subjects with right hemisphere damage made simple sequencing errors and substituted similar actions whereas the subjects with left hemisphere damage and aphasia made more complex errors and made only a few related substitutions. When subjects were asked to produce a sequence from memory,
the subjects with left hemisphere damage made more errors than subjects with right hemisphere damage and the errors tended to be repetitive. In addition, the subjects with left hemisphere damage and aphasia made more unrelated substitutions and perseverative errors. Error analysis during performance of sequential movements has not been done in children except for informal observations which seem to indicate that children make perservative errors [10]. Yet, Roy [8] proposed that error analysis may provide insight into the behavioral processes involved in dyspraxia and apraxia. While the etiology of adult onset apraxia and developmental dyspraxia is clearly different, there is some data to suggest that individuals with apraxia and dyspraxia have difficulty with the same types of tasks [11]. However, the tasks used in previous studies were single movements and not movement sequences. The purpose of the present study was to examine and compare abilities of children and young adults with developmental dyspraxia and adults with apraxia to learn and retain two tasks: a functional meaningful task (one handed shoe-tying) and a meaningless task (hand sequence). A second purpose was to examine and compare errors made while performing the two sequence tasks. Age matched control groups were used to control for differences due to age. 2. Methods 2.1. Subjects
Six groups of subjects were included in this study: children with dyspraxia and learning disabilities, control children, young adults with dyspraxia and learning disabilities, control young adults, older adults with left hemisphere brain damage and apraxia and control older adults. Subject were selected based on convenience and age. Additional criteria for the dyspraxic / apraxic groups required subjects to score below the cut-off score for dyspraxia/apraxia on the De Renzi, Pieczuro and Vignolo Test of Apraxia [12,13] and have a full-scale Wechsler Intelligence Scale score
J.L. Poole / NeuroRehabilitation 10 (1998) 75-82
of at least 85. The age criterion was 9-11 years for children, 18-30 years for the young adults and 60-75 years for the older adults. Subjects in the group of children with dyspraxia had to score 19 or below on the children's version of the DeRenzi, Pieczuro and Vignolo Test of Apraxia [13] while the young adults with dyspraxia and older adults with apraxia had to receive a score of 17 or below on the adult version of the DeRenzi, Pieczuro and Vignolo Test of Apraxia [12]. Subjects in the control groups had to score above these cut-off scores. All groups had 10 subjects except for the young adult group with dyspraxia. Only eight subjects could be recruited who had dyspraxia and were in the predetermined age range and met the criteria described above. 2. 2. Children with dyspraxia
Subjects in this group ranged in age from 9.0 to 10.4 years (mean = 9.60), were suspected of being dyspraxic by an occupational therapist in a school setting and had a diagnosis of learning disability. On the Wechsler Intelligence Scale, their full scale scores ranged from 85 to 99 (mean = 89.1). There were five males and five females. 2.3. Control children
Subjects in this group consisted of non-dyspraxic children who were age-matched to the children with dyspraxia. The age range of this group was 9.2-10.4 years (mean = 9.73 years). These children had no known learning, behavioral, or neurological deficits as reported by their parents. There were four males and six females. 2.4. Dyspraxic learning disabled young adults
Subjects in this group were college students who were suspected of being dyspraxic by the director of the special services departments at the college and had a diagnosis of learning disability. They ranged in age from 18 to 28 years (mean = 21.70 years). On the Wechsler Intelligence Scale, their full scale scores ranged from 85 to 99 (mean = 90.6). There were four males and four females.
77
2.5. Control young adults
These subjects were age matched to the young adults with learning disabilities and dyspraxia. They ranged in age from 18.6 to 25.3 years (mean = 21.6 years). They reported no known learning, behavioral, or neurological deficits. There were five males and five females. 2.6. Apraxic left hemisphere brain damaged older adults
The subjects in this group consisted of subjects with left hemisphere damage from a stroke who were living at home who were suspected of having apraxia by a neuropsychologist and had vascular damage lateralized to the left hemisphere as ascertained by physicians' reports. They ranged in age from 60 to 75.1 years (mean = 68.7 years). There were six males and four females. The mean length of time since the stroke was 3 years, 10 months with a range from 1 year to 8 years, 2 months. 2. 7. Control older adults
These subjects were age matched to the subjects with stroke and ranged in age from 60.5 to 73.7 years (mean = 68.6 years). They had no known history of learning, behavioral, or neurological deficits as reported by the subject and/or family. There were five males and five females. The mean ages of the children in both the dyspraxia and control groups were similar as were the ages of the young adults in both the dyspraxia and control groups and the older adults in both the apraxia and control groups. In addition, the mean lOs of the children with dyspraxia and the young adults with dyspraxia were similar. 10 tests scores were not available for the older adults with left hemisphere brain damage and apraxia. 2.8. Tasks and procedures
Subjects were tested individually in a quiet room and performed the tasks with their preferred hand. Subjects were videotaped for the purpose of error analysis.
78
J.L. Poole / NeuroRehabilitation 10 (1998) 75-82
2.8.1. One-handed shoe tying The shoe was already laced in such a fashion that only one lace was available for tying. The task involved three basic steps: (1) putting the end of the lace through the top lace so that a loop remained; (2) inserting the thumb and index finger through the loop to pinch the rest of the lace; and (3) pulling on the lace to bring it though the loop to form a knot with one loop [14]. Subjects' scores for learning this task were the number of trials needed to perform the task correctly. The task was discontinued after five trials as a pilot study showed that subjects either learned the task on the fifth trial or became too frustrated to continue. Subjects unable to perform the task successfully in five trials were given a score of 7. To ascertain retention, subjects were asked to tie the shoe again after a delay of approximately 5 min. During the 5-min retention interval, subjects performed an apraxia screening test, the Luria sequence described below and gestures in response to verbal command and imitation [11]. The score again was the number of trials needed to tie the shoe correctly. The types of errors made on each trial were also recorded. The errors that could be made on the shoe tying tasks were sequencing, omission, perseveratioR, internal configuration and external configuration. An error was scored a sequencing error if the subject performed the sequence out of order, forgot a step, or forgot to insert the thumb and index finger through the loop to pinch the shoelace. A perseveration error was scored if the subject repeated the first step which consisted of putting the end of the shoelace back through the top lace or back through the loop. An error was scored as an internal configuration error if the subject's thumb and index finger kept moving to the end of the lace while pulling the lace through the loop to form a knot. In this instance, a knot was formed without a loop. The correct method consisted of keeping the thumb and index finger in one place on the lace while pinching the lace to pull it through the loop to make a knot with one loop. An external configuration error consisted of making the initial loop too big so that when the lace is pulled to form a knot, the
end of the lace comes back through the loop to form a knot without a loop. 2.8.2. Luria's hand sequence task This task consisted of three hand sequences: a fist, the palm flat and horizontal and the palm flat and vertical [15]. Subjects were tested with the preferred hand first and then the non-preferred hand. The score for each hand was the number of trials needed to perform the sequence 10 times in a row without any errors as per Motomura et al. [7]. If an error was made, the instructions were given again and the test repeated. The test was discontinued if subjects were unable to successfully complete the 10 sequences after five trials as a pilot study showed that subjects either learned the task on the fifth trial or became too frustrated to continue. Subjects unable to perform the task successfully in five trials were given a score of 7. A lower score meant less trials were needed, that is, better performance. To assess retention, subjects were asked to correctly perform the sequence 10 times in a row with each hand approximately 5 min later. During the 5-min retention interval, subjects performed gestures in response to verbal command and imitation and the shoe tying retention task. The score for the retention task was again, the number of trials needed to correctly perform the sequence 10 times in a row without any errors. In addition, the types of errors made on each trial were determined. Errors were scored as sequencing or perseveration. A sequencing error was made if the steps in the sequence were incorrect or steps were omitted, such as making a fist, palm of hand flat vertically, palm of hand flat horizontally and then a fist. A perseveration error was made if the subject repeated the previous step of part of the previous step, such as making a fist in the vertical position and then a fist in a horizontal position. 2.8.3. Reliability Before beginning the study, intrarater and interrater reliability were established for both tasks. To establish intrarater reliability, the author reviewed videotapes of 10 subjects two times, 1
J.L. Poole / NeuroRehabilitation 10 (1998) 75-82
79
Table 1 Mean number of trials for shoe tying learning and retention task for control and subjects with dyspraxia/apraxia Shoe learning
Control children Dyspraxia children Control young adults Dyspraxia young adults Control older adults Apraxia older adults
Shoe retention
n
Mean (No. Trials)
S.D.
Mean (No. Trials)
S.D.
10 10 10 8 10 10
1.8 4.9 1.0 6.0 1.5 4.1
1.3 2.0 0.0 2.1 0.7 2.3
1.3 2.6 1.0 3.1 1.0 2.6
0.48 2.0 0.0 2.3 0.0 1.8
week apart. Percent of agreement was 90% for the shoe tying task and 100% for the hand sequence task. To establish interrater reliability, an occupational therapist familiar with the scoring procedures reviewed videotapes of the same 10 subjects. Percent of agreement was 90% for both tasks.
trials was better than performance during the learning trials. The trial x diagnosis interaction (F j ,52 = 23.01, P < 0.0001) was also significant so although all groups performed better during retention, the groups with dyspraxia/apraxia improved more. Neither age nor any other interactions were significant.
3. Results
3.2. Learning/retention trials on Luria hand sequence
3.1. Learning/retention trials on the shoe tying task
Table 1 shows the mean scores for each group for the shoe tying tasks. Analysis of variance with repeated measures showed main effects for diagnosis (F j 52 = 56.08, P < 0.0001) and trial (F j 52 = 42.08, P 0.0001). Thus, the control groups 'performed better than the groups with dyspraxia/ apraxia and performance during the retention
