Abstract
Inroduction
Complex visual hallucinations occur in 70% of dementia with Lewy bodies (DLB) cases and significantly affect patient wellbeing. However, the pathological changes that give rise to these symptoms remain unknown. The visual thalamic circuitry, including the lateral geniculate nucleus (LGN), pulvinar and superior colliculus, have an important role in relaying incoming visual information and also in directing visual attention and selecting visual targets.
Materials and methods
Post-mortem tissue was obtained from the visual thalamic structures in DLB cases with a clinical history of visual hallucinations and compared with non-hallucinating Alzheimer's disease (AD) and aged control cases using stereological and quantitative neuropathological methods.
Results
In DLB cases, Lewy body pathology was only found in the pulvinar and superior colliculus, with relative sparing of the LGN. In DLB, neuronal loss was specifically found in regions of the pulvinar and superior colliculus implicated in visual attention and target selection. In contrast, AD cases had more widespread pathological changes and neuronal loss.
Conclusion
These results indicate more specific pathological changes in the visual thalamic circuitry in DLB, compared to AD. Previous studies have suggested dysfunction in visual attention and target selection may be related to visual hallucinations in DLB. As the present study reports pathological changes in regions involved in visual attention and target selection, it may be speculated that such changes contribute to the manifestation of visual hallucinations in DLB.
Complex visual hallucinations occur in 70% of dementia with Lewy bodies (DLB) cases and significantly affect patient wellbeing. However, the pathological changes that give rise to these symptoms remain unknown. The visual thalamic circuitry, including the lateral geniculate nucleus (LGN), pulvinar and superior colliculus, have an important role in relaying incoming visual information and also in directing visual attention and selecting visual targets.
Materials and methods
Post-mortem tissue was obtained from the visual thalamic structures in DLB cases with a clinical history of visual hallucinations and compared with non-hallucinating Alzheimer's disease (AD) and aged control cases using stereological and quantitative neuropathological methods.
Results
In DLB cases, Lewy body pathology was only found in the pulvinar and superior colliculus, with relative sparing of the LGN. In DLB, neuronal loss was specifically found in regions of the pulvinar and superior colliculus implicated in visual attention and target selection. In contrast, AD cases had more widespread pathological changes and neuronal loss.
Conclusion
These results indicate more specific pathological changes in the visual thalamic circuitry in DLB, compared to AD. Previous studies have suggested dysfunction in visual attention and target selection may be related to visual hallucinations in DLB. As the present study reports pathological changes in regions involved in visual attention and target selection, it may be speculated that such changes contribute to the manifestation of visual hallucinations in DLB.
| Original language | English |
|---|---|
| Pages (from-to) | 13 |
| Number of pages | 1 |
| Journal | Neuropathology and Applied Neurobiology |
| Volume | 43 |
| Issue number | S1 |
| Publication status | Published - 1 Feb 2017 |