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Conditional associative learning examined in a paralyzed patient with amyotrophic lateral sclerosis using brain-computer interface technology.

Iversen I, Ghanayim N, Kübler A, Neumann N, Birbaumer N, Kaiser J - Behav Brain Funct (2008)

Bottom Line: A smiley was presented as a reward when he hit the correct target.In contrast, the patient showed clear evidence that A-B and B-C training had resulted in formation of equivalence classes.The brain-computer interface technology combined with the matching to sample method is a useful way to assess various cognitive abilities of severely paralyzed patients, who are without reliable motor control.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Medical Psychology, Goethe-University, Frankfurt am Main, Germany. j.kaiser@med.uni-frankfurt.de.

ABSTRACT

Background: Brain-computer interface methodology based on self-regulation of slow-cortical potentials (SCPs) of the EEG (electroencephalogram) was used to assess conditional associative learning in one severely paralyzed, late-stage ALS patient. After having been taught arbitrary stimulus relations, he was evaluated for formation of equivalence classes among the trained stimuli.

Methods: A monitor presented visual information in two targets. The method of teaching was matching to sample. Three types of stimuli were presented: signs (A), colored disks (B), and geometrical shapes (C). The sample was one type, and the choice was between two stimuli from another type. The patient used his SCP to steer a cursor to one of the targets. A smiley was presented as a reward when he hit the correct target. The patient was taught A-B and B-C (sample - comparison) matching with three stimuli of each type. Tests for stimulus equivalence involved the untaught B-A, C-B, A-C, and C-A relations. An additional test was discrimination between all three stimuli of one equivalence class presented together versus three unrelated stimuli. The patient also had sessions with identity matching using the same stimuli.

Results: The patient showed high accuracy, close to 100%, on identity matching and could therefore discriminate the stimuli and control the cursor correctly. Acquisition of A-B matching took 11 sessions (of 70 trials each) and had to be broken into simpler units before he could learn it. Acquisition of B-C matching took two sessions. The patient passed all equivalence class tests at 90% or higher.

Conclusion: The patient may have had a deficit in acquisition of the first conditional association of signs and colored disks. In contrast, the patient showed clear evidence that A-B and B-C training had resulted in formation of equivalence classes. The brain-computer interface technology combined with the matching to sample method is a useful way to assess various cognitive abilities of severely paralyzed patients, who are without reliable motor control.

No MeSH data available.


To assess possible learning within sessions, performance on individual trials (correct or incorrect) is shown for selected sessions. Session number is indicated in parenthesis for each data set. For the first teaching sessions with A → B and B → C relations (sessions 1 and 14, respectively), the data are shown for the first 24 trials of each session. For the test sessions with B → A, C → B, A → C, and C → A relations (sessions 12, 16, 18, 20, and 27), the data are shown for all probe trials (12 per session). For the whole class tests, data are shown for the first 12 trials of the first session of each test (sessions 40 and 41).
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Figure 6: To assess possible learning within sessions, performance on individual trials (correct or incorrect) is shown for selected sessions. Session number is indicated in parenthesis for each data set. For the first teaching sessions with A → B and B → C relations (sessions 1 and 14, respectively), the data are shown for the first 24 trials of each session. For the test sessions with B → A, C → B, A → C, and C → A relations (sessions 12, 16, 18, 20, and 27), the data are shown for all probe trials (12 per session). For the whole class tests, data are shown for the first 12 trials of the first session of each test (sessions 40 and 41).

Mentions: Because the patient received a smiley as positive feedback on all correct trials through the experiment, a natural question is whether the overall correct performance on probe test trials reflected learning during prior training sessions or reflected quick learning during the probe trials. To answer this question, the data were analyzed at the level of individual probe trials for the first session of each test type. Fig. 6 shows correct or incorrect selection on each trial of probe testing (12 trials each test session) and in comparison also for the first 24 trials of the first session of A → B training and the first session of B → C training, where the stimulus relations were new to the patient. If the probed relations had to be learned during testing, one would expect probe trial performance to resemble performance during sessions with learning of new relations. The A → B and B → C relations were learned slowly over several sessions (11 sessions for the A → B relation and 2 sessions for the B → C relations, Figs. 4 and 5), and correct selections in the beginning of the first sessions of these relations did not lead to quick learning (Fig. 6). In contrast, during probe trials in test sessions, the patient made very few if any mistakes from the beginning of probe trials, indicating that the relations the probes trial tested for were not learned during testing. Only during the first A → C probe test did the patient perform poorly, as already described above, and there was no indication of quick learning after one or two correct trials (Fig. 6). Thus, the overall data suggest that the patient did not learn the test relations from feedback during the first few probe trials at the beginning of a test session. Instead, the performance on probe test trials indicated that the patient selected the correct stimulus during probe testing based on learning during prior training sessions.


Conditional associative learning examined in a paralyzed patient with amyotrophic lateral sclerosis using brain-computer interface technology.

Iversen I, Ghanayim N, Kübler A, Neumann N, Birbaumer N, Kaiser J - Behav Brain Funct (2008)

To assess possible learning within sessions, performance on individual trials (correct or incorrect) is shown for selected sessions. Session number is indicated in parenthesis for each data set. For the first teaching sessions with A → B and B → C relations (sessions 1 and 14, respectively), the data are shown for the first 24 trials of each session. For the test sessions with B → A, C → B, A → C, and C → A relations (sessions 12, 16, 18, 20, and 27), the data are shown for all probe trials (12 per session). For the whole class tests, data are shown for the first 12 trials of the first session of each test (sessions 40 and 41).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2599893&req=5

Figure 6: To assess possible learning within sessions, performance on individual trials (correct or incorrect) is shown for selected sessions. Session number is indicated in parenthesis for each data set. For the first teaching sessions with A → B and B → C relations (sessions 1 and 14, respectively), the data are shown for the first 24 trials of each session. For the test sessions with B → A, C → B, A → C, and C → A relations (sessions 12, 16, 18, 20, and 27), the data are shown for all probe trials (12 per session). For the whole class tests, data are shown for the first 12 trials of the first session of each test (sessions 40 and 41).
Mentions: Because the patient received a smiley as positive feedback on all correct trials through the experiment, a natural question is whether the overall correct performance on probe test trials reflected learning during prior training sessions or reflected quick learning during the probe trials. To answer this question, the data were analyzed at the level of individual probe trials for the first session of each test type. Fig. 6 shows correct or incorrect selection on each trial of probe testing (12 trials each test session) and in comparison also for the first 24 trials of the first session of A → B training and the first session of B → C training, where the stimulus relations were new to the patient. If the probed relations had to be learned during testing, one would expect probe trial performance to resemble performance during sessions with learning of new relations. The A → B and B → C relations were learned slowly over several sessions (11 sessions for the A → B relation and 2 sessions for the B → C relations, Figs. 4 and 5), and correct selections in the beginning of the first sessions of these relations did not lead to quick learning (Fig. 6). In contrast, during probe trials in test sessions, the patient made very few if any mistakes from the beginning of probe trials, indicating that the relations the probes trial tested for were not learned during testing. Only during the first A → C probe test did the patient perform poorly, as already described above, and there was no indication of quick learning after one or two correct trials (Fig. 6). Thus, the overall data suggest that the patient did not learn the test relations from feedback during the first few probe trials at the beginning of a test session. Instead, the performance on probe test trials indicated that the patient selected the correct stimulus during probe testing based on learning during prior training sessions.

Bottom Line: A smiley was presented as a reward when he hit the correct target.In contrast, the patient showed clear evidence that A-B and B-C training had resulted in formation of equivalence classes.The brain-computer interface technology combined with the matching to sample method is a useful way to assess various cognitive abilities of severely paralyzed patients, who are without reliable motor control.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Medical Psychology, Goethe-University, Frankfurt am Main, Germany. j.kaiser@med.uni-frankfurt.de.

ABSTRACT

Background: Brain-computer interface methodology based on self-regulation of slow-cortical potentials (SCPs) of the EEG (electroencephalogram) was used to assess conditional associative learning in one severely paralyzed, late-stage ALS patient. After having been taught arbitrary stimulus relations, he was evaluated for formation of equivalence classes among the trained stimuli.

Methods: A monitor presented visual information in two targets. The method of teaching was matching to sample. Three types of stimuli were presented: signs (A), colored disks (B), and geometrical shapes (C). The sample was one type, and the choice was between two stimuli from another type. The patient used his SCP to steer a cursor to one of the targets. A smiley was presented as a reward when he hit the correct target. The patient was taught A-B and B-C (sample - comparison) matching with three stimuli of each type. Tests for stimulus equivalence involved the untaught B-A, C-B, A-C, and C-A relations. An additional test was discrimination between all three stimuli of one equivalence class presented together versus three unrelated stimuli. The patient also had sessions with identity matching using the same stimuli.

Results: The patient showed high accuracy, close to 100%, on identity matching and could therefore discriminate the stimuli and control the cursor correctly. Acquisition of A-B matching took 11 sessions (of 70 trials each) and had to be broken into simpler units before he could learn it. Acquisition of B-C matching took two sessions. The patient passed all equivalence class tests at 90% or higher.

Conclusion: The patient may have had a deficit in acquisition of the first conditional association of signs and colored disks. In contrast, the patient showed clear evidence that A-B and B-C training had resulted in formation of equivalence classes. The brain-computer interface technology combined with the matching to sample method is a useful way to assess various cognitive abilities of severely paralyzed patients, who are without reliable motor control.

No MeSH data available.