Biomedical subjects

Joukje van der Naalt

Publications and source records attributed to Joukje van der Naalt.

3 recordsLinked to original sources

PubMed2005

P300 after head injury: pseudodelay caused by reduced P3A amplitude.

OBJECTIVE: We compared conventional P300 analysis with source analysis in normal subjects and head-injury patients. Based on earlier findings of improved P300 component identification and reduced P3B latency variability with source analysis in normal subjects, our aim was to investigate whether source analysis could improve the distinction between these groups. METHODS: In total, 21 healthy control subjects and 21 patients with mild to moderate head injury were included in this study. A standard auditory 2-tone oddball paradigm was used. Latencies and amplitudes obtained with conventional P300 analysis were compared with source analysis results. RESULTS: With conventional analysis, head-injury patients had delayed P300 latencies and reduced P300 amplitudes in comparison to controls, while source analysis showed no latency differences for both P3A and P3B components. Instead, source analysis indicated absence of P3A components in 43% of patients. CONCLUSIONS: The P300 delay in head-injury patients, observed with conventional analysis, is a pseudodelay caused by decreased P3A amplitudes. Consequently, the unaffected P3B component with its later latency determines conventional P300 latency in these patients. SIGNIFICANCE: Conventional P300 latency cannot be used to conclude that there was delayed early stimulus processing in head-injury patients.

Adult↗

PubMed2005

Cluster-like headache aura status.

We describe a patient with successive attacks (40 to 90 minutes) of cluster-like headache associated with aphasia, and contralateral hemihypesthesia and hemiplegia. The condition can best be described as cluster-like headache aura status.

Adult↗

PubMed2004

Indices of slowness of information processing in head injury patients: tests for selective attention related to ERP latencies.

We explored the relation between neuropsychological (attention tests involving time constraints) and neurophysiological (N2 and P3 event-related potential (ERP) latencies) indices of slowness of information processing after closed head injury (CHI). A group of 44 CHI patients performed worse than healthy controls on most neuropsychological indices, and had significantly longer ERP latencies. Significant correlations between neuropsychological measures and ERP latencies were found only for the 3 subtasks of the Stroop test. In additional multiple regression analyses P3 latency appeared the best predictor in Stroop Color only. A possible explanation is that stimulus evaluation processes comprise a relatively large part of performance on this subtask. In Stroop Color-Word, response related processes are supposed to play a greater role, reducing the role of the preceding input related processes. The absence of significant correlations between P3 latency and scores on the other attention tests suggests a relatively small role of stimulus evaluation processes in these tasks, implying that these tasks are not sensitive to slowness of these processes. The Stroop test appears to be the only attention test administered in which slowness in stimulus evaluation processes requiring selective attention contributes significantly to the delay in final performance on the task.

Adolescent↗