Memory-delineated subtypes of schizophrenia: Relationship to clinical, neuroanatomical, and neurophysiological measures.

Abstract

Memory performance was examined in patients with schizophrenia to determine whether subgroups conforming to cortical and subcortical dementias could be identified and, if so, whether subgroups differed on clinical, neuroanatomical, and neurophysiological measures. A cluster analysis of California Verbal Learning Test performance classified patients into 3 subgroups. Two groups exhibited memory deficits consistent with the cortical-subcortical distinction, whereas 1 group was unimpaired. Cortical patients tended to be male, and they had earlier illness onset, reduced temporal lobe gray matter, and hypometabolism. Subcortical patients had ventricular enlargement and more negative symptoms. Unimpaired patients had fewer negative symptoms and dorsal medial prefrontal hypermetabolism. The authors conclude that categorizing patients on the basis of memory deficits may yield neurobiologically meaningful disease subtypes.

Subtyping schizophrenia: implications for genetic research

“…Another 15% had a cortical (hippocampal-thalamic, AD-type) profile (primary encoding and storage impairment, with an excess of irrelevant word intrusions on free and cued recall), while the profiles of the remaining 35% did not deviate significantly from those of the controls. These findings were replicated by Turetsky et al 237 and supported by neuroimaging data suggesting ventricular enlargement with preserved temporal lobe grey matter and no significant metabolic abnormalities in the subcortical group. In contrast, the cortical group was characterized by a left-hemisphere temporal and frontal volume reduction, and metabolic abnormalities in the superior temporal gyrus, hippocampus, and thalamus.…”

“…Converging evidence from endophenotype-based studies suggests that measures of neurocognitive dysfunction arguably provide the largest effect sizes and increases in relative risk to relatives among a host of 'candidate' endophenotypes, 236,237,241,281,294,295 being also cost efficient for phenotyping large samples. In particular, several characteristic patterns of short-term and working memory impairment against a background of generalized cognitive deficit have been replicated across studies and are present in a substantial proportion (B50%) of schizophrenia patients.…”

“…Subtyping schizophrenia A Jablensky 823 205 Prepulse inhibition of the startle reflex [206][207][208] Deficient gating of the auditory evoked response (P50) [209][210][211] P300 amplitude reduction and latency delay 212 N400 amplitude reduction (semantic context underutilization) 213 Mismatch negativity (MMN) [214][215][216][217] Smooth pursuit eye movement dysfunction (SPEM) [218][219][220][221] Antisaccade error rate (AS) [222][223][224] Composite inhibitory phenotype (P50, AS, SPEM) 225 Multivariate electrophysiological endophenotype (MMN, P50, P300, AS) 226 Neuroimaging markers and endophenotypes Fronto-thalamic-cerebellar gray matter deficit 227 Fronto-striato-thalamic gray matter deficit 228 MRI-derived three-factor phenotype 229 MRI whole-brain nonlinear pattern classification 230 Frontal hypoactivation in response to cognitive tasks (hypofrontality) 231 Atrophic and static (neurodevelopmental) schizophrenia endophenotypes 232 Cognitive markers and endophenotypes Continuous performance tests (CPT, signal/noise ratio) [233][234][235] Attention and vigilance-based subtype 18 Verbal dysmnesic subtype 18 Verbal memory deficit, cortical or subcortical type 236,237 Dysexecutive subtype 18 Prefrontal executive/working memory phenotype 238 Frontal/abstraction deficit profile 239 Spatial working memory 240...…”

Functional deactivations: Change with age and dementia of the Alzheimer type

“…However, in the schizophrenia literature there are also reports of patients showing functional activations in regions where control subjects show deactivations and that correspond to regions where patients have reduced resting metabolism (41)(42)(43). Taken together, these patterns suggest that the relation between functional activity patterns and resting metabolism needs further investigation.…”

The Development of Data Infrastructures for eHealth: A Socio-Technical Perspective

“…As evidenced at the HealthGrid workshop on schizophrenia, 8 there is some dispute among clinicians as to whether this can even be considered a single disease classification, or is simply an umbrella term for a variety of conditions as Turetsky et al (2002) suggest. Many common diseases are multi-factorial and open to a wide range of shifting interpretations and reinterpretations in the light of emerging findings.…”