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Relationship between serial EEG and the brain-stem auditory evoked response (BAER) in Creutzfeldt-Jakob disease
S196 correlate closely with disease severity. In certain cases where the diagnosis may be borderline comparison of the CPI score with the latency of the P~ component of the pattern reversal VEP has proved useful. A weighting factor utilising the VEP results has been included in the CPI score for use in testing cases of Alzheimer's Disease.
largest at Pz both in patients and controls groups, in some patients, P300 latency became shorter and WAIS score increased after oral administration of Physostigmine.
P36.04 S H O R T - L A T E N C Y S O M A T O S E N S O R Y EVOKED P O T E N T I A L S IN DEMENTIA: C O R R E L A T I O N W I T H CT SCAN FINDINGS.
P36.02 FLASH AND PAT'FERN VEPS IN DEMENTIA. L. Reni, G. Abbruzzese, D. Dall'Agata, G. Bino and E. Favale M.A. Danesi, P. Huxley and N.M.F. Murray (Genoa, Italy) (London UK) The use of flash and pattern-reversal visual evoked potentials (VEPs) in the diagnosis of dementia was investigated. VEPs to single flashes of light at 2 / s e c and pattern reversal at 2 / s e c were recorded in patients with degenerative and vascular dementia and in age-matched controls. There was a marked delay in the P2 component of the flash VEP (mean 153 msec) in demented subjects compared with controls (mean 127 msec). The P1 component of the flash VEP in dementia (74 msec) and controls (76 msec) were not significantly different. The latency of the P100 component of the pattern-reversal VEP in demented subjects (105 msec) was similar to that found in controls (103 msec). This study is in agreement with earlier work (Wright et al. Electroenceph. clin. Neurophysiol. 1984, 54; 405) and suggests that measurement of flash and pattern-reversal VEPs is of value in the investigation of presenile dementia.
P36.03 LATE P O S I T I V E C O M P O N E N T S O F EVOKED P O T E N T I A L S (P300) IN T H E CLINCAL S T U D Y O F DEMENTIA. R. Neshige, G. Barrett and H. Shibasaki
We have recently shown that abnormalities of short-latency somatosensory evoked potentials (SEPs) occur frequently in patients affected by multi-infarct dementia as compared with patients with senile dementia of the Alzheimer type or agematched normal controls (Abbruzzese et aI,JNNP, 1984 47;1034). In the present study the relationships between CT scan findings and SEP abnormalities (prolonged central conduction time, increased height-covariated N20 latency, reduction of primary cortical response amplitude) were investigated in a large group of demented patients. SEPs were normal in patients without focal brain lesions, in spite of a remarkable cortical atrophy. The occurrence of SEP abnormalities was not related to the number or size of CT scan ischemic areas, but was critically dependent on their anatomical location within the cerebral hemispheres. Even small lesions (less than 1 cm 3) in the putaminal-thalamic complex or in the pre-postcentral regions (constantly involving the white matter) were associate with SEP abnormalities, whilst patients with large lesions (up to 25 cm 3) located in the prefrontal region or in the temporal and occipital lobes presented normal SEPs. These findings suggest that diffuse cortical neuronal loss in dementia is not relevant to the occurrence of SEP changes, which are due to the involvement (i.e. axonal loss and segmental demyelination) of the thalamocorticat pathway or of specific brain areas.
(Saga City, Japan) Auditory event-related potentials elicited in a target stimulus detection paradigm were studied in patients with Alzheimer's disease or multi-infarct dementia. The stimulus was a pure tone delivered binaurally at 75 dB SPL with a frequency of 1 kHz (frequent, 85%) or 2 kHz (target, 15%). Subjects had to respond to a target either by pressing a button or by counting. EEG was recorded from electrodes at Fz, C3, Cz, C4, P3, Pz and P4 using a time constant of 3 sec, and averaged. P300 in healthy subjects is described in a companion presentation. All demented patients were evaluated on Wechsler Adult Intelligence Scale (WAIS). 5 patients in each group were treated with oral administration of Physostigmine. P300 latency in most patients was longer as compared with age-matched controls and correlated significantly with the WAIS score. Patients with Alzheimer's disease had shorter P300 latency, smaller standard deviation and more significant correlation with WAIS score as compared with multi-infarct dementia. As for scalp topography, P300 was
P36.05 RELATIONSHIP BETWEEN SERIAL EEG A N D T H E BRAIN-STEM AUDITORY EVOKED R E S P O N S E (BAER) IN CREUTZFELDT-JAKOB DISEASE.
E.A. Delarnonica (Buenos Aires, Argentina) Creutzfeldt-Jakob disease (CJD) is at present classified as a subacute spongiform encephalopathy, induced by a slow virus. Pathological study (electron microscopy) shows an ample spongiform alteration, neuronal gliosis and necrobiosis, disseminated in the brain cortex, the cerebellum and the spinal cord. In the study of Masters and Richardson (1978) and that of Ribedeau D u m a s and Escourelle (1974), the neurones of the brain-stem were not affected. Two cases of CJD diagnosed by brain biopsy, have been
S197 studied by means of the EEG and BAER. Both cases showed the characteristic pattern (generalized periodic triphasic waves) from the beginning as well as changes in the BAER. During the course of the disease the coma of the patients became deeper, the background activity of the EEG deteriorated and concomitantly the BAER deteriorated. The conclusion is that in these cases the brain-stem was affected from the beginning of the disease and that their alteration progressed together with the evolution of the disease. Besides~ it may be theorized that the characteristic EEG pattern may be of subcortical origin due to the brain-stem being functionally affected by chemical changes following reduction of the oxidative metabolism.
P36.06 CEREBRAL EVOKED P O T E N T I A L S IN C R E U T Z F E L D T - J A K O B DISEASE W I T H R E F E R E N C E T O PERIO D I C S Y N C H R O N O U S D I S C H A R G E S (PSD).
phase (NPSD). During the PSD phase, the PSI) continued to appear with E M G activity, contrary to NPSD, in which PSD disappeared and muscle tone tonus became flaccid. The PSD, respiration, pulse rate and muscle tonus were very closely correlated with those two sleep phases. Respiration was suppressed in rate and depth as to become frequently apnoeic in NPSD; also the pulse rate was slower than during PSD phase. SER and PER evoked by PSD-triggered-stimuli with serial delay were analysed in order to evaluate the recovery curves of the response amplitudes. The recovery curves suggested the presence of a relative cortical refractory period after the peak of PSD, lasting for about one half of a second. These results suggested that the formation of the periodicity of PSD was closely correlated with both the subcortical (brain-stem) and cortical functions.
P36.08 DIFFERENT TYPES OF EEG IN C O R R E L A T I O N W I T H SPECIAL G R O U P S O F SENILE DEMENTIA.
H. Kamttsuchihashi and A. Igata H. Boehmer and L. Gutjahr (Kagoshima, Japan) (Berlin, W. Germany) Two cases of typical Creutzfeldt-Jakob disease were reported. The two patients were 57 and 55-year-old males. The first case showed a markedly exaggerated response to flashes of light 10 months after the onset of the disease. A slow stimulation rate of 0.5 and 1 / s e c evoked prominent sharp waves over the head region. At flash rates above 3/sec, responses to individual stimuli could no longer be seen, but evoked sharp waves were noted at the onset of stimulation. An 'off response' was seen with more than 20/see stimulation. At the same time, a high amplitude visual evoked potential (VEP) and a somatosensory evoked potential (SEP) were recorded in this patient. The recovery' curves of VEP suggested the presence of a relative cortical refractory period lasting approximately half a second. In the second case, at the same time PSD disappeared in the EEG, L-Dopa was administered intravenously by drip for two hours. After the L-Dopa infusion, in a dose of 500 mg the EEG recording showed PSD. This finding points to the role played by dopamine in the pharmacological mechanism of PSD.
P36.07 S T U D I E S O N P A T H O P H Y S I O L O G Y OF PERIODIC SYNCHRONOUS DISCHARGE ( P S D ) IN C R E U T Z F E L D T J A K O B DISEASE (CJD). H. Umezaki, S. Noda, A. Minato, A. Itch, K. Goto and M. Suetsugu
Clinical, psychometric and electrophysiological measurements were acquired from 40 patients with Senile Dementia. Three groups of EEG characteristics could be correlated with clinical and psychometric findings: Group A: patients with a normal background activity in the EEG; Group B: patients with regular slowing of background activity in the EEG; Group C: patients with irregular slowing of background activity in the EEG. While group A and B were only significantly different in reaction-time, group A and C showed significant differences in almost all psychometric tests. The main characteristics for group C were the loss of orientation and the disturbance of memory functions. Group B compared with group A shows a slowing of psychic features, correlated with the slowing of EEG background activity. The nosological correlate for group C may be Alzheimer's disease, the clinical correlate for group B still remains unknown. The discriminant-analysis shows a classification rate of over 80% with the EEG as grouping variable and the psychometric parameters as dependant variables.
P36.09 EEG FINDINGS IN SENILE D E M E N T I A O F ALZHEIMER-TYPE. Christine Logar
(Kishinoura, Japan) (Graz, Austria) PSD was observed in all of the 121 cases with CJD in serial EEGs so far examined. The peak interval most frequently seen in the established PSD was 600-700 msec. All-night sleep polygraphy was performed on 6 nights in 4 cases. Two phases of the polygram were identified, i.e., a PSD and a non-PSD
The character and extent of EEG in 45 patients with senile dementia of the Alzheimer type (SDAT) were studied and the EEG-diagnoses of patients with moderate (18) or severe (27) dementia were compared. The EEG-diagnoses in these patients
largest at Pz both in patients and controls groups, in some patients, P300 latency became shorter and WAIS score increased after oral administration of Physostigmine.
P36.04 S H O R T - L A T E N C Y S O M A T O S E N S O R Y EVOKED P O T E N T I A L S IN DEMENTIA: C O R R E L A T I O N W I T H CT SCAN FINDINGS.
P36.02 FLASH AND PAT'FERN VEPS IN DEMENTIA. L. Reni, G. Abbruzzese, D. Dall'Agata, G. Bino and E. Favale M.A. Danesi, P. Huxley and N.M.F. Murray (Genoa, Italy) (London UK) The use of flash and pattern-reversal visual evoked potentials (VEPs) in the diagnosis of dementia was investigated. VEPs to single flashes of light at 2 / s e c and pattern reversal at 2 / s e c were recorded in patients with degenerative and vascular dementia and in age-matched controls. There was a marked delay in the P2 component of the flash VEP (mean 153 msec) in demented subjects compared with controls (mean 127 msec). The P1 component of the flash VEP in dementia (74 msec) and controls (76 msec) were not significantly different. The latency of the P100 component of the pattern-reversal VEP in demented subjects (105 msec) was similar to that found in controls (103 msec). This study is in agreement with earlier work (Wright et al. Electroenceph. clin. Neurophysiol. 1984, 54; 405) and suggests that measurement of flash and pattern-reversal VEPs is of value in the investigation of presenile dementia.
P36.03 LATE P O S I T I V E C O M P O N E N T S O F EVOKED P O T E N T I A L S (P300) IN T H E CLINCAL S T U D Y O F DEMENTIA. R. Neshige, G. Barrett and H. Shibasaki
We have recently shown that abnormalities of short-latency somatosensory evoked potentials (SEPs) occur frequently in patients affected by multi-infarct dementia as compared with patients with senile dementia of the Alzheimer type or agematched normal controls (Abbruzzese et aI,JNNP, 1984 47;1034). In the present study the relationships between CT scan findings and SEP abnormalities (prolonged central conduction time, increased height-covariated N20 latency, reduction of primary cortical response amplitude) were investigated in a large group of demented patients. SEPs were normal in patients without focal brain lesions, in spite of a remarkable cortical atrophy. The occurrence of SEP abnormalities was not related to the number or size of CT scan ischemic areas, but was critically dependent on their anatomical location within the cerebral hemispheres. Even small lesions (less than 1 cm 3) in the putaminal-thalamic complex or in the pre-postcentral regions (constantly involving the white matter) were associate with SEP abnormalities, whilst patients with large lesions (up to 25 cm 3) located in the prefrontal region or in the temporal and occipital lobes presented normal SEPs. These findings suggest that diffuse cortical neuronal loss in dementia is not relevant to the occurrence of SEP changes, which are due to the involvement (i.e. axonal loss and segmental demyelination) of the thalamocorticat pathway or of specific brain areas.
(Saga City, Japan) Auditory event-related potentials elicited in a target stimulus detection paradigm were studied in patients with Alzheimer's disease or multi-infarct dementia. The stimulus was a pure tone delivered binaurally at 75 dB SPL with a frequency of 1 kHz (frequent, 85%) or 2 kHz (target, 15%). Subjects had to respond to a target either by pressing a button or by counting. EEG was recorded from electrodes at Fz, C3, Cz, C4, P3, Pz and P4 using a time constant of 3 sec, and averaged. P300 in healthy subjects is described in a companion presentation. All demented patients were evaluated on Wechsler Adult Intelligence Scale (WAIS). 5 patients in each group were treated with oral administration of Physostigmine. P300 latency in most patients was longer as compared with age-matched controls and correlated significantly with the WAIS score. Patients with Alzheimer's disease had shorter P300 latency, smaller standard deviation and more significant correlation with WAIS score as compared with multi-infarct dementia. As for scalp topography, P300 was
P36.05 RELATIONSHIP BETWEEN SERIAL EEG A N D T H E BRAIN-STEM AUDITORY EVOKED R E S P O N S E (BAER) IN CREUTZFELDT-JAKOB DISEASE.
E.A. Delarnonica (Buenos Aires, Argentina) Creutzfeldt-Jakob disease (CJD) is at present classified as a subacute spongiform encephalopathy, induced by a slow virus. Pathological study (electron microscopy) shows an ample spongiform alteration, neuronal gliosis and necrobiosis, disseminated in the brain cortex, the cerebellum and the spinal cord. In the study of Masters and Richardson (1978) and that of Ribedeau D u m a s and Escourelle (1974), the neurones of the brain-stem were not affected. Two cases of CJD diagnosed by brain biopsy, have been
S197 studied by means of the EEG and BAER. Both cases showed the characteristic pattern (generalized periodic triphasic waves) from the beginning as well as changes in the BAER. During the course of the disease the coma of the patients became deeper, the background activity of the EEG deteriorated and concomitantly the BAER deteriorated. The conclusion is that in these cases the brain-stem was affected from the beginning of the disease and that their alteration progressed together with the evolution of the disease. Besides~ it may be theorized that the characteristic EEG pattern may be of subcortical origin due to the brain-stem being functionally affected by chemical changes following reduction of the oxidative metabolism.
P36.06 CEREBRAL EVOKED P O T E N T I A L S IN C R E U T Z F E L D T - J A K O B DISEASE W I T H R E F E R E N C E T O PERIO D I C S Y N C H R O N O U S D I S C H A R G E S (PSD).
phase (NPSD). During the PSD phase, the PSI) continued to appear with E M G activity, contrary to NPSD, in which PSD disappeared and muscle tone tonus became flaccid. The PSD, respiration, pulse rate and muscle tonus were very closely correlated with those two sleep phases. Respiration was suppressed in rate and depth as to become frequently apnoeic in NPSD; also the pulse rate was slower than during PSD phase. SER and PER evoked by PSD-triggered-stimuli with serial delay were analysed in order to evaluate the recovery curves of the response amplitudes. The recovery curves suggested the presence of a relative cortical refractory period after the peak of PSD, lasting for about one half of a second. These results suggested that the formation of the periodicity of PSD was closely correlated with both the subcortical (brain-stem) and cortical functions.
P36.08 DIFFERENT TYPES OF EEG IN C O R R E L A T I O N W I T H SPECIAL G R O U P S O F SENILE DEMENTIA.
H. Kamttsuchihashi and A. Igata H. Boehmer and L. Gutjahr (Kagoshima, Japan) (Berlin, W. Germany) Two cases of typical Creutzfeldt-Jakob disease were reported. The two patients were 57 and 55-year-old males. The first case showed a markedly exaggerated response to flashes of light 10 months after the onset of the disease. A slow stimulation rate of 0.5 and 1 / s e c evoked prominent sharp waves over the head region. At flash rates above 3/sec, responses to individual stimuli could no longer be seen, but evoked sharp waves were noted at the onset of stimulation. An 'off response' was seen with more than 20/see stimulation. At the same time, a high amplitude visual evoked potential (VEP) and a somatosensory evoked potential (SEP) were recorded in this patient. The recovery' curves of VEP suggested the presence of a relative cortical refractory period lasting approximately half a second. In the second case, at the same time PSD disappeared in the EEG, L-Dopa was administered intravenously by drip for two hours. After the L-Dopa infusion, in a dose of 500 mg the EEG recording showed PSD. This finding points to the role played by dopamine in the pharmacological mechanism of PSD.
P36.07 S T U D I E S O N P A T H O P H Y S I O L O G Y OF PERIODIC SYNCHRONOUS DISCHARGE ( P S D ) IN C R E U T Z F E L D T J A K O B DISEASE (CJD). H. Umezaki, S. Noda, A. Minato, A. Itch, K. Goto and M. Suetsugu
Clinical, psychometric and electrophysiological measurements were acquired from 40 patients with Senile Dementia. Three groups of EEG characteristics could be correlated with clinical and psychometric findings: Group A: patients with a normal background activity in the EEG; Group B: patients with regular slowing of background activity in the EEG; Group C: patients with irregular slowing of background activity in the EEG. While group A and B were only significantly different in reaction-time, group A and C showed significant differences in almost all psychometric tests. The main characteristics for group C were the loss of orientation and the disturbance of memory functions. Group B compared with group A shows a slowing of psychic features, correlated with the slowing of EEG background activity. The nosological correlate for group C may be Alzheimer's disease, the clinical correlate for group B still remains unknown. The discriminant-analysis shows a classification rate of over 80% with the EEG as grouping variable and the psychometric parameters as dependant variables.
P36.09 EEG FINDINGS IN SENILE D E M E N T I A O F ALZHEIMER-TYPE. Christine Logar
(Kishinoura, Japan) (Graz, Austria) PSD was observed in all of the 121 cases with CJD in serial EEGs so far examined. The peak interval most frequently seen in the established PSD was 600-700 msec. All-night sleep polygraphy was performed on 6 nights in 4 cases. Two phases of the polygram were identified, i.e., a PSD and a non-PSD
The character and extent of EEG in 45 patients with senile dementia of the Alzheimer type (SDAT) were studied and the EEG-diagnoses of patients with moderate (18) or severe (27) dementia were compared. The EEG-diagnoses in these patients