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Papers by Rowena Chin

Research paper thumbnail of Shared and Divergent Neurocognitive Impairments in Adult Patients with Schizophrenia and Bipolar Disorder: Whither the evidence?

Recent data from genetic and brain imaging studies have urged rethinking of bipolar disorder (BD)... more Recent data from genetic and brain imaging studies have urged rethinking of bipolar disorder (BD) and schizophrenia (SCZ) as lying along a continuum of major endogenous psychoses rather than dichotomous disorders. We systematically reviewed extant studies (from January 2000 to July 2015) that directly compared neurocognitive impairments in adults with SCZ and BD. Within 36 included studies, comparable neurocognitive impairments were found in SCZ and BD involving executive functioning, working memory , verbal fluency and motor speed. The extent and severity of neurocognitive impairments in patients with schizoaffective disorder, and BD with psychotic features occupy positions intermediate between SCZ and BD without psychotic features, suggesting spectrum of neurocognitive impairments across psychotic spectrum conditions. Neurocognitive impairments correlated with socio-demographic (lower education), clinical (more hospitalizations, longer duration of illness, negative psychotic symptoms and non-remission status), treatment (antipsychotics, anti-cholinergics) variables and lower psychosocial functioning. The convergent neurocognitive findings in both conditions support a continuum concept of psychotic disorders and further research is needed to clarify common and dissimilar progression of specific neurocognitive impairments longitudinally.

Research paper thumbnail of Clinical associations of anosognosia in mild cognitive impairment and Alzheimer's disease

Aims and objective: While loss of insight of cognitive deficits is a common phenomenon in patient... more Aims and objective: While loss of insight of cognitive deficits is a common phenomenon in patients with Alzheimer’s disease (AD), there is a lack of consensus regarding the presence of impaired insight among patients with mild cognitive impairment (MCI). We aim to investigate the clinical, cognitive, and be- havioral associations of anosognosia in AD and MCI subjects.
Methods: A consecutive series of 87 subjects (30 healthy older patients, 21 MCI, and 36 AD) each ac- companied by a caregiver, underwent clinical assessment including the evaluation of insight using the Anosognosia Questionnaire for Dementia (AQD). We also separately assessed Intellectual Function (AQD-IF) and Behavior domains of the AQD scale. Regression models were subsequently used to inves- tigate associations of AQD scores with cognitive and other neuropsychiatric symptoms, including de- pression and apathy.
Results: Both AD and MCI groups demonstrated significant anosognosia compared with the healthy control group. In the AD group, 55.6% had “Mild Anosognosia,” and 27.8% had “Severe Anosognosia.” In the MCI group, 42.9% showed “Mild Anosognosia,” and 9.5% had “Severe Anosognosia.” Greater levels of AQD-Total and AQD-IF were associated with lower Mini-mental state examination and higher apathy scores in the AD group. In the MCI group, caregiver burden was significantly associated with AQD-Total (p = 0.016) and AQD-IF (p = 0.039).
Conclusion: The results indicated that anosognosia is common in both AD and MCI patients and asso- ciated with cognitive dysfunction and apathy in AD. The findings of this study warrant further research to delineate the mechanisms of anosognosia as it poses a challenge to treatment outcomes.

Research paper thumbnail of Utility of the AD8 as a Self-Rating Tool for Cognitive Impairment in an Asian Population

Background: AD8 is a brief informant interview used to detect early cognitive change. This study ... more Background: AD8 is a brief informant interview used to detect early cognitive change. This study evaluated the diagnostic performance of the participant-rated AD8 (p-AD8) in a predominantly Chinese population. Methods: Data on demographics, clinical, and cognitive features were collected from 73 participants with no cognitive impairment (NCI), 27 participants with mild cognitive impairments, and 78 participants with Alzheimer’s disease–informant dyads. Agreement and discriminative properties of p-AD8 were assessed. Results: AD8 scores were associated with dementia severity. Participant and informant AD8 scores were moderately correlated within dementia dyads. The p-AD8 showed good diagnostic performance in differentiating between participants with NCI and participants with cognitive impairment (sensitivity 1⁄4 85.0%, specificity 1⁄4 74.0%, and area under the curve 1⁄4 0.80), with a cutoff score of 􏰀1. Combination of impairment in Mini-Mental State Examination and p-AD8 is more useful in detecting cognitive impairment than using the AD8 alone. Conclusion: Within a transcultural setting, the p-AD8 demon- strated good discriminative validity and can be used to gain a preliminary understanding of an individual’s cognitive status.

Research paper thumbnail of Shared and Divergent Neurocognitive Impairments in Adult Patients with Schizophrenia and Bipolar Disorder: Whither the evidence?

Recent data from genetic and brain imaging studies have urged rethinking of bipolar disorder (BD)... more Recent data from genetic and brain imaging studies have urged rethinking of bipolar disorder (BD) and schizophrenia (SCZ) as lying along a continuum of major endogenous psychoses rather than dichotomous disorders. We systematically reviewed extant studies (from January 2000 to July 2015) that directly compared neurocognitive impairments in adults with SCZ and BD. Within 36 included studies, comparable neurocognitive impairments were found in SCZ and BD involving executive functioning, working memory , verbal fluency and motor speed. The extent and severity of neurocognitive impairments in patients with schizoaffective disorder, and BD with psychotic features occupy positions intermediate between SCZ and BD without psychotic features, suggesting spectrum of neurocognitive impairments across psychotic spectrum conditions. Neurocognitive impairments correlated with socio-demographic (lower education), clinical (more hospitalizations, longer duration of illness, negative psychotic symptoms and non-remission status), treatment (antipsychotics, anti-cholinergics) variables and lower psychosocial functioning. The convergent neurocognitive findings in both conditions support a continuum concept of psychotic disorders and further research is needed to clarify common and dissimilar progression of specific neurocognitive impairments longitudinally.

Research paper thumbnail of Clinical associations of anosognosia in mild cognitive impairment and Alzheimer's disease

Aims and objective: While loss of insight of cognitive deficits is a common phenomenon in patient... more Aims and objective: While loss of insight of cognitive deficits is a common phenomenon in patients with Alzheimer’s disease (AD), there is a lack of consensus regarding the presence of impaired insight among patients with mild cognitive impairment (MCI). We aim to investigate the clinical, cognitive, and be- havioral associations of anosognosia in AD and MCI subjects.
Methods: A consecutive series of 87 subjects (30 healthy older patients, 21 MCI, and 36 AD) each ac- companied by a caregiver, underwent clinical assessment including the evaluation of insight using the Anosognosia Questionnaire for Dementia (AQD). We also separately assessed Intellectual Function (AQD-IF) and Behavior domains of the AQD scale. Regression models were subsequently used to inves- tigate associations of AQD scores with cognitive and other neuropsychiatric symptoms, including de- pression and apathy.
Results: Both AD and MCI groups demonstrated significant anosognosia compared with the healthy control group. In the AD group, 55.6% had “Mild Anosognosia,” and 27.8% had “Severe Anosognosia.” In the MCI group, 42.9% showed “Mild Anosognosia,” and 9.5% had “Severe Anosognosia.” Greater levels of AQD-Total and AQD-IF were associated with lower Mini-mental state examination and higher apathy scores in the AD group. In the MCI group, caregiver burden was significantly associated with AQD-Total (p = 0.016) and AQD-IF (p = 0.039).
Conclusion: The results indicated that anosognosia is common in both AD and MCI patients and asso- ciated with cognitive dysfunction and apathy in AD. The findings of this study warrant further research to delineate the mechanisms of anosognosia as it poses a challenge to treatment outcomes.

Research paper thumbnail of Utility of the AD8 as a Self-Rating Tool for Cognitive Impairment in an Asian Population

Background: AD8 is a brief informant interview used to detect early cognitive change. This study ... more Background: AD8 is a brief informant interview used to detect early cognitive change. This study evaluated the diagnostic performance of the participant-rated AD8 (p-AD8) in a predominantly Chinese population. Methods: Data on demographics, clinical, and cognitive features were collected from 73 participants with no cognitive impairment (NCI), 27 participants with mild cognitive impairments, and 78 participants with Alzheimer’s disease–informant dyads. Agreement and discriminative properties of p-AD8 were assessed. Results: AD8 scores were associated with dementia severity. Participant and informant AD8 scores were moderately correlated within dementia dyads. The p-AD8 showed good diagnostic performance in differentiating between participants with NCI and participants with cognitive impairment (sensitivity 1⁄4 85.0%, specificity 1⁄4 74.0%, and area under the curve 1⁄4 0.80), with a cutoff score of 􏰀1. Combination of impairment in Mini-Mental State Examination and p-AD8 is more useful in detecting cognitive impairment than using the AD8 alone. Conclusion: Within a transcultural setting, the p-AD8 demon- strated good discriminative validity and can be used to gain a preliminary understanding of an individual’s cognitive status.

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