Manual motor speed dysfunction as a neurocognitive endophenotype in euthymic bipolar disorder patients and their healthy relatives. Evidence from a 5-year follow-up study.

BACKGROUND: Few studies have examined Manual Motor Speed (MMS) in bipolar disorder (BD). The aim of this longitudinal, family study was to explore whether dysfunctional MMS represents a neurocognitive endophenotype of BD. METHODS: A sample of 291 subjects, including 131 BD patients, 77 healthy first-degree relatives (BD-Rel), and 83 genetically-unrelated healthy controls (HC), was assessed with the Finger-Tapping Test (FTT) on three occasions over a 5-year period. Dependence of FTT on participants´ age was removed by means of a lineal model of HC samples, while correcting simultaneously the time and learning effect. Differences between groups were evaluated with an ANOVA test. RESULTS: The patients' performance was significantly worse than that of HC over time (p≤0.006), and these deficits remained when non-euthymic BD patients (n=9) were excluded from analysis. Some significant differences between BD patients and BD-Rel (p≤0.037) and between BD-Rel and HC (p≤0.033) were found, but they tended to disappear as time progressed (p≥0.057). Performance of the BD-Rel group was intermediate to that of BD and HC. Most sociodemographic and clinical variables did not affect these results in patients. (p≥0.1). However, treatment with carbamazepine and benzodiazepines may exert a iatrogenic effect on MMS performance (p≤0.006). LIMITATIONS: Only right-handed subjects were included in this study. Substantial attrition over time was detected. CONCLUSIONS: There were significant differences between the patients´ MMS performance and that of healthy relatives and controls, regardless of most clinical and sociodemographic variables. Dysfunctional MMS could be considered an endophenotype of BD. Further studies are needed to rule out possible iatrogenic effects of some psychopharmacological treatments.

Motor speed predicts stability of cognitive deficitsin both schizophrenic and bipolar I patients at oneyearfollow-up

Background: We examined whether motor speed assessed by the fingertapping test predicts generalized and specific stable deficits because of a common pathogenicprocess in bipolar and schizophrenic patients.Methods: One hundred and two patients underwent a battery of neuropsychologicaltests. Patients with a score of less than one standard deviation from their siblings’ samplein two assessments with an interval of one year were defined as suffering from stabledeficits because of a common pathogenic process. In addition to univariate analyses, factoranalyses, ordinal logistic regression, and multiple linear regressions were used. A generalscore was also calculated. Results: No differences were found between schizophrenic and bipolar patients in thedeficits of verbal fluency, shift reasoning ability and executive attention. Schizophrenicpatients had greater persistent cognitive deficit because of a common pathogenic factor inthe verbal memory dimension than bipolar patients. Motor speed predicted the specificdeficits of verbal fluency, shift reasoning, executive attention and the general deficit ofboth bipolar I and schizophrenic patients. Bipolar patients suffered a lesser specific deficitin the verbal memory dimension than schizophrenic patients did, this domain not beingpredicted by motor speed. Motor speed predicted the generalized deficit and the specificdimensions in which schizophrenic and bipolar patients showed no differences.Conclusions: These results suggest the presence of general and specific stable cognitivedeficits because of a common pathogenic factor related to psychomotor slowness. Motorspeed seems to be suitable endophenocognitype for schizophrenia and bipolar disorder (AU)

Recall and recognition confabulation in psychotic and bipolar disorders: evidence for two different types without unitary mechanisms.

Several forms of confabulation have been identified recently in schizophrenic patients, but it has not yet been investigated whether these forms are specific to schizophrenia. Furthermore, the origin of confabulation is unclear. The present study investigated recall and recognition confabulation and their relations with symptomatology, cognitive domains (abstraction and flexibility, verbal fluency, verbal memory, motor activity, and visual-motor processing/attention), computed tomographic (CT) measures (ventricular, cerebral, and Sylvian fissure size), and auditory event-related potentials (amplitudes and latencies of peak components in oddball paradigms) in 33 schizophrenic patients, 35 bipolar I patients, eight schizoaffective patients, and seven patients with other psychotic disorders. We found that neither type of confabulation was specific of any diagnostic group. Recall confabulation was mainly predicted by the predominance of positive symptoms, while recognition confabulation was predicted by a delay in P300 latency and the doses of antipsychotics used. Our results suggest two different mechanisms for both types of confabulation based on interference with the adequate retrieval of information and slowness in early stimulus detection.

[Neurophysiology and neuropsychology of recognition confabulation in hospitalized schizophrenic patients]. / Neuropsicología y neurofisiología de la confabulación de reconocimiento en pacientes esquizofrénicos hospitalizados.

Recognition confabulation was studied in 16 schizoprhenic patients and 16 normal controls. Half of the schizophrenics presented recognition confabulation, while the remaining 8 and 16 controls did not. This type of confabulation was associated to attentional deficiency, difficulties in perceptual follow-up and perceptive changes. These test satisfactorily discriminated confabulating schizoprhenics and both ill and healthy non-confabulating subjects. The possible mechanisms underlying this type of confabulation are discussed, in relation to the deficiences observed.