International Journal of Neuroscience
ISSN: 0020-7454 (Print) 1543-5245 (Online) Journal homepage: http://www.tandfonline.com/loi/ines20
Short-Latency Somatosensory Evoked Potential and Event-Related Potential in Patients with Multiple Cerebral Infarcts Hisao Tachibana, Masanaka Takeda & Minoru Sugita To cite this article: Hisao Tachibana, Masanaka Takeda & Minoru Sugita (1991) Short-Latency Somatosensory Evoked Potential and Event-Related Potential in Patients with Multiple Cerebral Infarcts, International Journal of Neuroscience, 61:1-2, 1-8, DOI: 10.3109/00207459108986266 To link to this article: http://dx.doi.org/10.3109/00207459108986266
Published online: 07 Jul 2009.
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Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ines20 Download by: [RMIT University Library]
Date: 08 May 2016, At: 03:08
0 1991 Gordon and Breach Science Publishers S . A .
Intern. J . Neuroscience, 1991, Val. 61, pp. 1-8
Printed in the United States of America
Reprints available directly from the publisher Photocopying permitted by license only
SHORT-LATENCY SOMATOSENSORY EVOKED POTENTIAL AND EVENT-RELATED POTENTIAL IN PATIENTS WITH MULTIPLE CEREBRAL INFARCTS HISAO TACHIBANA, MASANAKA TAKEDA and MINORU SUGITA
Downloaded by [RMIT University Library] at 03:08 08 May 2016
The Fifth Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya 663, JAPAN (Received February 14, 1991)
Although the short-latency somatosensory evoked (SSEPs) and the cognitive event-related potentials (ERPs) have been found to change in patients with cerebral vascular disease, the relationship between these paramaters has yet to be determined. For clarification of this relationship, SSEPs and ERPs were measured in 33 patients with multiple cerebral infarcts (MCI) and 25 age-matched normal subjects. ERPs were recorded during auditory discrimination tasks. The latency of P300 from the Pz region was measured. SSEPs evoked by median nerve stimulation were recorded from the second cervical vertebra and contralateral primary somatosensory cortex with a midfrontal reference. The central conduction time (CCT), the interpeak latency between N13 and N20, was measured. P300 latency in patients with MCI was significantly longer than that of the normal subjects. Patients with MCI also showed longer CCT than the normal subjects. CCT and P300 latency were significantly correlated in patients with MCI. This correlation was not found in normal subjects. From these results, the severity of the lesion with respect to SSEPs appears related to the prolongation of P300 latency in patients with MCI. Keywords: short-latency somatosensory evoked potential (SSEP); central conduction time (CCT);eventrelated potential (ERP); P300; multiple cerebral infarcts.
The clinical usefulness of short-latency somatosensory evoked potential (SSEP) studies of various focal and diffuse brain disorders has been intensively reported. Although N20 has been found to be a sensitive parameter, the central conduction time (CCT), assessed as the interpeak latency between N13 (N14) and N20 at the somatosensory cortex following median nerve stimulation at the wrist, since it is unrelated to subject height and is usually unaffected by conditions resulting in slowing of peripheral conduction velocity, has been widely used as a diagnostic index of brain injury (Hume et al., 1978; Hume et al., 1979; Symon et al., 1979; Fox and Williams, 1984). Abnormal CCT has been found to occur even in patients with pure motor hemiplegia (Chokroverty and Rubin, 1975; Ganji, 1984). On the other hand, the P300 component of the event-related potentials (ERPs) has been shown to be associated with various cognitive processes and to reflect changes in brain function associated with a variety of brain diseases including cerebral vascular disease (CVD) (Goodin et al., 1978; Pfurtscheller et al., 1980; Canter et al., 1982; Hansch et al., 1982; Gummow et al., 1986). Although SSEPs in patients with CVD have been investigated in a number of clinical studies, ERP, which is related This paper was presented at the Fourth International Evoked Potentials Symposium (Toronto, 1990). The authors wish to thank Miss H. Tanaka for typing the present menuscript. Mailing Address: Hisao Tachibana, M.D., The Fifth Department of Internal Medicine, Hyogo College of Medicine, 1-1, Mukogawa-cho, Nishinomiya 663, JAPAN I
2
H. TACHTBANA, M . TAKEDA AND M. SUGITA
to cognitive processing, has received less attention, and the relation between both modifications has yet to be determined. The purpose of the present study was to measure the SSEPs and ERPs in patients with multiple cerebral infarcts (MCI), and to determine the relationship between CCT and the P300 component.
Downloaded by [RMIT University Library] at 03:08 08 May 2016
MATERIALS AND METHODS The study was performed on 33 patients with MCl, aged 46-81 years (mean, 62.7 -+ 10.9 years), and 25 age-matched normal subjects, aged 50-77 yeras (mean, 61.3 rt 7.7 years), without history of relevant neurological diseases or drug abuse. Patients with MCI had bilateral CT evidence of small cerebral infarction involving internal capsule, thalamus, corona radiata, basal ganglia and subcortical white matter. N o brainstem lesions were identified on CT in any of the patients studied. All patients had measurement of evoked potentials 1 month or more following their most recent episode of cerebral infarction. Only two patients met the criteria for dementia as outlined in DSM-111-R (American Psychiatric Association, 1987). SSEPs were simultaneously recorded from the second cervical vertebra (C2) and the contralateral primary sensory cortex (7 cm lateral and 2 cm posterior from vertex; Shagass and Schwartz, 1964) with a midfrontal reference (Fpz). The median nerve at the wrist was stimulated at a rate of 5 Hz and with a duration of .2 ms with bipolar surface electrodes (cathode proximally). The stimulation intensity was adjusted to produce a small thumb twitch and for each patient was set at the same intensity bilaterally. The responses were amplified 100,000 times with a filter setting of 203000 Hz. Averaged potentials to 256 pulses were obtained. Values determined were peak latencies (N13, N20) and CCT, which is the interpeak latency between N13 and N20. ERPs were also recorded in a sound-attenuated electrically shielded chamber. Each subject participated in an oddball paradigm using auditory stimulation. The stimulus was a pure tone delivered binaurally through light headphones at an intensity of 60 dB nHL and with an interstimulus interval of 2.0 s. Tones of two different frequencies, 1 KHz and 2 KHz, were presented at rates of 80 and 20%, respectively, in a random order. The subject responded to the target stimulus by pressing a pushbutton with his index finger. A total of 32 auditory stimuli were generated as targets. EEG activity was recorded from scalp electrodes at Fz, Cz and Pz (International 1020 system) which were referred to linked earlobe electrodes. Interelectrode impedance was maintained at below 5 Kohm. The EEG was amplified with filter settings of .5-100 Hz. The P300 component was defined as the largest positive-going potential at the Pz site. The latency was defined as time in milliseconds from stimulus onset to identified component. The results obtained were expressed as means k standard deviations (SD). All statistical procedures were performed using Student’s t-test to compare different groups, and Pearson’s r was calculated to determine correlations. RESULTS The actual SSEPs and ERPs in a patient with MCI and in a normal subject are shown in Fig. 1. Both the CCT and P300 latency in the patient with MCI were increased compared to those in the normal subject.
SSEP AND ERP IN CEREBRAL VASCULAR DISEASE
SSEPs evoked bv right median nerve stimulation
3
h
Cortex-Fpz
C2-Fpz
Y
. 10
. 20
.
30
. 40
rns
. 50 ms
Downloaded by [RMIT University Library] at 03:08 08 May 2016
SSEPs evoked by left median nerve stimulation Cortex-Fpz Cz-Fpz
10
20
30
40
50
10
20
30
40
50 rns
rns
Fzw
ERPs to rare tones
CZ
P
~
p
440-
y
f 392
200 400 600 800
Patient with MCI (74yrs, Female)
ms
200 400 600 800
ms
Normal Subject (73yrs. Male)
FIGURE 1 Actual SSEPs and ERPs to rare (target) tones in a patient with MCI and in a normal subject Both CCT and P300 latency are prolonged in the patient with MCI compared to those of the normal subject.
Table 1 shows the peak latencies of N13 and N20, CCT and P300 latency in patients with MCI and in age-matched normal subjects. The peak N13 and N20 latencies in patients with MCI were significantly prolonged compared with those of normal subjects ( p < .01, in each case). Patients with MCI also had longer CCTs than did the normal subjects ( p < .05 in each side). On the other hand, a significant difference in P300 latency was found between the two groups ( p < .02). When CCT values exceeding 2.0 SD above the normal mean were classified as abnormal, 1 1 patients were found to have CCT abnormalities, while 6 patients had abnormal P300 latency. There was a correlation between the mean CCT values and P300 latency in patients with MCI ( p < . O l ) as shown in Fig. 2. This correlation did not exist among normal subjects (r = -.204, p > . 1 > .
H . TACHIBANA, M. TAKEDA AND M. SUGITA
4
TABLE 1 Comparisons of the Peak Latencies of N13 and N20, CCT and P300 Latency Between Patients with MCI and Normal Subjects MCI N13 N20
Normals ~
*
13.45 0.90** 13.27 ? 1.04** 20.10 1.05** 19.80 t 0.88** 6.64 -c n . 8 ~ 6.52 0.61* 394.8 28.0**
f
12.44 t 0.59 12.33 0.58 18.71 0.73 18.57 0.77 6.27 0.42 6.24 0.41 375.0 -+ 25.7
* * *
*
i
* *
CCT P300
Downloaded by [RMIT University Library] at 03:08 08 May 2016
*
Values are means SD(ms). r or I: SSEPs evoked by the right or left median nerve stimulation
* < '05 * * p < .01
1
compared to normals
0
+
Y =.0112X 2.15 r =.524
0
o
A
A
0
0
A
o CVD A Normals
0
r = -.204. n.s. 1
I
I
350
400
450
(ms)
P300 Latency FIGURE 2 Relationship between mean CCT and P300 latency in patients with MCI and normal subjects Significant correlation between CCT and P300 latency is present among patients with MCI, but not among normal subjects.
5
SSEP AND ERP IN CEREBRAL VASCULAR DISEASE
'"1
(rns)
0 Rt-CbT
0 Lt-CCT
0
0
Rt-CCT Y=.0114X+2.13 r =.390,P
ISSN: 0020-7454 (Print) 1543-5245 (Online) Journal homepage: http://www.tandfonline.com/loi/ines20
Short-Latency Somatosensory Evoked Potential and Event-Related Potential in Patients with Multiple Cerebral Infarcts Hisao Tachibana, Masanaka Takeda & Minoru Sugita To cite this article: Hisao Tachibana, Masanaka Takeda & Minoru Sugita (1991) Short-Latency Somatosensory Evoked Potential and Event-Related Potential in Patients with Multiple Cerebral Infarcts, International Journal of Neuroscience, 61:1-2, 1-8, DOI: 10.3109/00207459108986266 To link to this article: http://dx.doi.org/10.3109/00207459108986266
Published online: 07 Jul 2009.
Submit your article to this journal
Article views: 3
View related articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ines20 Download by: [RMIT University Library]
Date: 08 May 2016, At: 03:08
0 1991 Gordon and Breach Science Publishers S . A .
Intern. J . Neuroscience, 1991, Val. 61, pp. 1-8
Printed in the United States of America
Reprints available directly from the publisher Photocopying permitted by license only
SHORT-LATENCY SOMATOSENSORY EVOKED POTENTIAL AND EVENT-RELATED POTENTIAL IN PATIENTS WITH MULTIPLE CEREBRAL INFARCTS HISAO TACHIBANA, MASANAKA TAKEDA and MINORU SUGITA
Downloaded by [RMIT University Library] at 03:08 08 May 2016
The Fifth Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya 663, JAPAN (Received February 14, 1991)
Although the short-latency somatosensory evoked (SSEPs) and the cognitive event-related potentials (ERPs) have been found to change in patients with cerebral vascular disease, the relationship between these paramaters has yet to be determined. For clarification of this relationship, SSEPs and ERPs were measured in 33 patients with multiple cerebral infarcts (MCI) and 25 age-matched normal subjects. ERPs were recorded during auditory discrimination tasks. The latency of P300 from the Pz region was measured. SSEPs evoked by median nerve stimulation were recorded from the second cervical vertebra and contralateral primary somatosensory cortex with a midfrontal reference. The central conduction time (CCT), the interpeak latency between N13 and N20, was measured. P300 latency in patients with MCI was significantly longer than that of the normal subjects. Patients with MCI also showed longer CCT than the normal subjects. CCT and P300 latency were significantly correlated in patients with MCI. This correlation was not found in normal subjects. From these results, the severity of the lesion with respect to SSEPs appears related to the prolongation of P300 latency in patients with MCI. Keywords: short-latency somatosensory evoked potential (SSEP); central conduction time (CCT);eventrelated potential (ERP); P300; multiple cerebral infarcts.
The clinical usefulness of short-latency somatosensory evoked potential (SSEP) studies of various focal and diffuse brain disorders has been intensively reported. Although N20 has been found to be a sensitive parameter, the central conduction time (CCT), assessed as the interpeak latency between N13 (N14) and N20 at the somatosensory cortex following median nerve stimulation at the wrist, since it is unrelated to subject height and is usually unaffected by conditions resulting in slowing of peripheral conduction velocity, has been widely used as a diagnostic index of brain injury (Hume et al., 1978; Hume et al., 1979; Symon et al., 1979; Fox and Williams, 1984). Abnormal CCT has been found to occur even in patients with pure motor hemiplegia (Chokroverty and Rubin, 1975; Ganji, 1984). On the other hand, the P300 component of the event-related potentials (ERPs) has been shown to be associated with various cognitive processes and to reflect changes in brain function associated with a variety of brain diseases including cerebral vascular disease (CVD) (Goodin et al., 1978; Pfurtscheller et al., 1980; Canter et al., 1982; Hansch et al., 1982; Gummow et al., 1986). Although SSEPs in patients with CVD have been investigated in a number of clinical studies, ERP, which is related This paper was presented at the Fourth International Evoked Potentials Symposium (Toronto, 1990). The authors wish to thank Miss H. Tanaka for typing the present menuscript. Mailing Address: Hisao Tachibana, M.D., The Fifth Department of Internal Medicine, Hyogo College of Medicine, 1-1, Mukogawa-cho, Nishinomiya 663, JAPAN I
2
H. TACHTBANA, M . TAKEDA AND M. SUGITA
to cognitive processing, has received less attention, and the relation between both modifications has yet to be determined. The purpose of the present study was to measure the SSEPs and ERPs in patients with multiple cerebral infarcts (MCI), and to determine the relationship between CCT and the P300 component.
Downloaded by [RMIT University Library] at 03:08 08 May 2016
MATERIALS AND METHODS The study was performed on 33 patients with MCl, aged 46-81 years (mean, 62.7 -+ 10.9 years), and 25 age-matched normal subjects, aged 50-77 yeras (mean, 61.3 rt 7.7 years), without history of relevant neurological diseases or drug abuse. Patients with MCI had bilateral CT evidence of small cerebral infarction involving internal capsule, thalamus, corona radiata, basal ganglia and subcortical white matter. N o brainstem lesions were identified on CT in any of the patients studied. All patients had measurement of evoked potentials 1 month or more following their most recent episode of cerebral infarction. Only two patients met the criteria for dementia as outlined in DSM-111-R (American Psychiatric Association, 1987). SSEPs were simultaneously recorded from the second cervical vertebra (C2) and the contralateral primary sensory cortex (7 cm lateral and 2 cm posterior from vertex; Shagass and Schwartz, 1964) with a midfrontal reference (Fpz). The median nerve at the wrist was stimulated at a rate of 5 Hz and with a duration of .2 ms with bipolar surface electrodes (cathode proximally). The stimulation intensity was adjusted to produce a small thumb twitch and for each patient was set at the same intensity bilaterally. The responses were amplified 100,000 times with a filter setting of 203000 Hz. Averaged potentials to 256 pulses were obtained. Values determined were peak latencies (N13, N20) and CCT, which is the interpeak latency between N13 and N20. ERPs were also recorded in a sound-attenuated electrically shielded chamber. Each subject participated in an oddball paradigm using auditory stimulation. The stimulus was a pure tone delivered binaurally through light headphones at an intensity of 60 dB nHL and with an interstimulus interval of 2.0 s. Tones of two different frequencies, 1 KHz and 2 KHz, were presented at rates of 80 and 20%, respectively, in a random order. The subject responded to the target stimulus by pressing a pushbutton with his index finger. A total of 32 auditory stimuli were generated as targets. EEG activity was recorded from scalp electrodes at Fz, Cz and Pz (International 1020 system) which were referred to linked earlobe electrodes. Interelectrode impedance was maintained at below 5 Kohm. The EEG was amplified with filter settings of .5-100 Hz. The P300 component was defined as the largest positive-going potential at the Pz site. The latency was defined as time in milliseconds from stimulus onset to identified component. The results obtained were expressed as means k standard deviations (SD). All statistical procedures were performed using Student’s t-test to compare different groups, and Pearson’s r was calculated to determine correlations. RESULTS The actual SSEPs and ERPs in a patient with MCI and in a normal subject are shown in Fig. 1. Both the CCT and P300 latency in the patient with MCI were increased compared to those in the normal subject.
SSEP AND ERP IN CEREBRAL VASCULAR DISEASE
SSEPs evoked bv right median nerve stimulation
3
h
Cortex-Fpz
C2-Fpz
Y
. 10
. 20
.
30
. 40
rns
. 50 ms
Downloaded by [RMIT University Library] at 03:08 08 May 2016
SSEPs evoked by left median nerve stimulation Cortex-Fpz Cz-Fpz
10
20
30
40
50
10
20
30
40
50 rns
rns
Fzw
ERPs to rare tones
CZ
P
~
p
440-
y
f 392
200 400 600 800
Patient with MCI (74yrs, Female)
ms
200 400 600 800
ms
Normal Subject (73yrs. Male)
FIGURE 1 Actual SSEPs and ERPs to rare (target) tones in a patient with MCI and in a normal subject Both CCT and P300 latency are prolonged in the patient with MCI compared to those of the normal subject.
Table 1 shows the peak latencies of N13 and N20, CCT and P300 latency in patients with MCI and in age-matched normal subjects. The peak N13 and N20 latencies in patients with MCI were significantly prolonged compared with those of normal subjects ( p < .01, in each case). Patients with MCI also had longer CCTs than did the normal subjects ( p < .05 in each side). On the other hand, a significant difference in P300 latency was found between the two groups ( p < .02). When CCT values exceeding 2.0 SD above the normal mean were classified as abnormal, 1 1 patients were found to have CCT abnormalities, while 6 patients had abnormal P300 latency. There was a correlation between the mean CCT values and P300 latency in patients with MCI ( p < . O l ) as shown in Fig. 2. This correlation did not exist among normal subjects (r = -.204, p > . 1 > .
H . TACHIBANA, M. TAKEDA AND M. SUGITA
4
TABLE 1 Comparisons of the Peak Latencies of N13 and N20, CCT and P300 Latency Between Patients with MCI and Normal Subjects MCI N13 N20
Normals ~
*
13.45 0.90** 13.27 ? 1.04** 20.10 1.05** 19.80 t 0.88** 6.64 -c n . 8 ~ 6.52 0.61* 394.8 28.0**
f
12.44 t 0.59 12.33 0.58 18.71 0.73 18.57 0.77 6.27 0.42 6.24 0.41 375.0 -+ 25.7
* * *
*
i
* *
CCT P300
Downloaded by [RMIT University Library] at 03:08 08 May 2016
*
Values are means SD(ms). r or I: SSEPs evoked by the right or left median nerve stimulation
* < '05 * * p < .01
1
compared to normals
0
+
Y =.0112X 2.15 r =.524
0
o
A
A
0
0
A
o CVD A Normals
0
r = -.204. n.s. 1
I
I
350
400
450
(ms)
P300 Latency FIGURE 2 Relationship between mean CCT and P300 latency in patients with MCI and normal subjects Significant correlation between CCT and P300 latency is present among patients with MCI, but not among normal subjects.
5
SSEP AND ERP IN CEREBRAL VASCULAR DISEASE
'"1
(rns)
0 Rt-CbT
0 Lt-CCT
0
0
Rt-CCT Y=.0114X+2.13 r =.390,P
