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Biomedical subjects

K H Chiappa

Publications and source records attributed to K H Chiappa.

At least 55 records · Page 3Linked to original sources
PubMed1988

Electroencephalography in AIDS and AIDS-related complex.

EEG records from 47 patients with the acquired immunodeficiency syndrome (AIDS) or AIDS-related complex (ARC) were reviewed retrospectively to correlate EEG findings with neurologic abnormalities. Abnormal EEGs were found in 22 of 33 (67%) patients with AIDS and 5 of 14 (36%) patients with ARC. Among 27 patients with abnormal EEGs, there were 9 patients with dementia, 10 with opportunistic infections of the CNS, and 6 with no apparent neurologic disease. AIDS dementia was associated with intermittent or continuous slowing, often most prominent anteriorly. Focal slowing or sharp activity was usually found in patients who had focal CNS processes, such as cerebral toxoplasmosis and CNS lymphoma. These findings suggest the EEG can be a useful diagnostic test for evaluating patients with AIDS and ARC, particularly when these patients present with seizures, psychiatric symptoms, or cognitive dysfunction. The significance of abnormal EEGs in patients who are neurologically asymptomatic is unknown.

AIDS-Related Complex↗
PubMed1988

Evoked potentials in motor system diseases.

We studied pattern-shift visual (PSVEP), brainstem auditory (BAEP), and somatosensory (SEP) evoked potentials in 38 unselected patients with motor system diseases (MSD) (28 sporadic, 10 familial). PSVEPs were normal in all patients, and BAEPs were normal in all except one with clinical hearing loss who had absent waves I and III and prolonged wave V latencies. Median and tibial SEPs revealed definite CNS conduction abnormalities in only 1 of 30 and 1 of 18 patients, respectively. In addition, four patients had peripheral and four had peripheral or central delays on tibial nerve testing. There were no or only small group differences in central conduction SEP, BAEP, and PSVEP values in patients with normal studies compared with controls. This study suggests that central conduction SEP, BAEP, or PSVEP abnormalities can rarely be attributed to MSD and that their presence in patients suspected of having this disorder should prompt a search for an alternative diagnosis.

Adult↗
PubMed1988

Use of evoked potentials for diagnosis of multiple sclerosis.

The author discusses visual evoked potentials, brain stem auditory evoked potentials, somatosensory evoked potentials, motor evoked potentials, and MRI for the diagnosis of MS. Most patients with MS will eventually have an MRI scan. However, certain specific questions regarding function and anatomic regions are better studied with evoked potentials, especially those of optic nerve, brain stem, and spinal cord.

Evoked Potentials, Auditory↗
PubMed1987

Normal temporal variability of the P100.

Determination of clinically significant temporal changes in P100 latency requires knowledge of the degree of normal intraindividual variability. Checkerboard visual evoked potentials using 3 check sizes (17', 35' and 70') were performed serially on 20 healthy volunteers. Each subject was tested at least twice an average of 6 months apart. The P100 latency was measured at Oz with a forehead reference (Pz, O1 and O2 channels were also recorded). The overall average P100 latency change between studies for all check sizes and both eyes was 2.9 msec. However, the maximum absolute latency change was 11 msec. There was no significant difference between the average latency change for the 3 check sizes. The P100 interocular difference changed a mean of 2.5 msec (maximum 9 msec). Amplitude was more variable, with a mean change of about 1.5 microV or 25% (maximum was a 60% decrease in amplitude). A P100 latency change of up to at least 11 msec needs to be acknowledged as normal when assessing the clinical significance of changes in P100 latencies in patients. Also, P100 latency changes greater than 11 or 12 msec are very suggestive of an abnormality in the visual pathway.

Adult↗
PubMed1986

Early evolution and incidence of electroencephalographic abnormalities in Creutzfeldt-Jakob disease.

The clinical and EEG findings in patients in the literature with Creutzfeldt-Jakob disease (CJD) were reviewed and compared with findings in 36 patients with CJD at the Massachusetts General Hospital (MGH). Twenty-one of the 36 MGH cases had histopathology, all with findings consistent with CJD. EEGs in 18 patients studied pathologically and in 10 without pathological investigation (28 of the 36) had periodic sharp wave complexes (PSWC) at some time during the clinical course. Of the other eight patients, two had only a single EEG early in the course of the illness, four experienced unusually long clinical courses, and two never showed PSWC despite numerous EEGs. PSWC made their appearance within 12 weeks of onset of clinical symptoms in 25 of 27 in whom EEGs were done during that period. In the early stages, EEGs in 14 of 28 showed focal PSWC or amplitude asymmetries of PSWC that corresponded well with focal myoclonus or other focal neurological abnormalities. In the literature, PSWC occurred within 12 weeks of the onset of the illness in 66 of 75 patients (88%) with CJD who had comparable clinical and neuropathological findings and adequate EEG data during the first 3 months of the illness. In the approximately 10% of patients who experienced unusually long courses, PSWC occurred in only about 55%. The presence of PSWC in association with the appropriate clinical, biochemical, cerebrospinal fluid, and neuroradiological findings is diagnostic of CJD. Brain biopsy is, therefore, unnecessary even when clinical therapeutic trials are undertaken and certainty of diagnosis is required. The absence of PSWC in the EEG after 12 weeks' duration of illness is a point strongly against the diagnosis of CJD unless it is a rare subtype of long duration. Only those patients without PSWC need to be biopsied.

Adult↗
PubMed1986

Evoked potentials in Guillain-Barré syndrome.

We studied evoked potentials (EPs) in 27 patients with typical acute Guillain-Barré syndrome and 3 with Fisher's syndrome. Three of 21 had BAEP abnormalities: 1 with bilateral I-III, 1 with unilateral I-III, and another with unilateral III-V interwave latency prolongations. Three with Fisher's syndrome had normal BAEPs (one had a poorly formed wave V unilaterally with one click polarity only). Ten of 21 median nerve EPs and 9 of 12 peroneal or tibial nerve somatosensory EPs were abnormal. Seven patients with normal somatosensory EPs had abnormal F waves from the same nerve; none had normal late responses and abnormal somatosensory EPs. These observations differ from previous reports on the frequency and interpretation of EP abnormalities in Guillain-Barré syndrome.

Adult↗
PubMed1982

Absence of evoked potential abnormalities in acute transverse myelopathy.

We studied 12 consecutive patients with inflammatory acute transverse myelopathy (ATM) and no prior history of neurologic disease. All had normal pattern shift visual and brainstem auditory evoked potentials. All of nine patients tested also had normal median nerve short-latency somatosensory evoked potentials. None developed new neurologic signs in 18 months' mean follow-up. In contrast, 72% of 50 patients with definite, probable, or possible multiple sclerosis (MS) had abnormalities in at least one evoked potential test. When defined as a virtually or completely transverse inflammatory lesion, acute transverse myelopathy differs from MS.

Adolescent↗