‘Two-level’ measurements of processing speed as cognitive markers in the differential diagnosis of DSM-5 mild neurocognitive disorders (NCD)

Abstract

Processing speed is an updated diagnostic factor for neurocognitive disorders (NCD) in DSM-5. This study investigated the characteristics of processing speed and their diagnostic values in NCD patients. A flanker test was conducted in 31 adults with NCD due to vascular disease (NCD-vascular), 36 patients with NCD due to Alzheimer’s disease (NCD-AD), and 137 healthy controls. The processing speed was evaluated using two measurements: mean reaction time (RT) and intra-individual variability of RT. Mean RT represents the global processing speed. Intra-individual variability of RT is the short-term fluctuation of RT and consists of two indices, which are intra-individual coefficient of variation of reaction time (ICV-RT) and intra-individual standard deviations (iSD). We observed elevated ICV-RT and iSD in NCD-AD and NCD-vascular patients. Additionally, there was a slowed RT in NCD-AD patients. The intra-individual variability of RT had a moderate power to differentiate NCD subgroups. The mean RT was able to discriminate the NCD-AD from NCD-vascular patients. Our findings highlight the clinical utility of the combined ‘two-level’ measurements of processing speed to distinguish between individuals with different cognitive status. Furthermore, the ‘two-level’ features of processing speed embedded in the psychometric property may also reflect the diverse aetiology underlying certain ‘disease-specific’ neurocognitive disorders.

Neuroimaging and biomarker evidence of neurodegeneration in asthma

“…The functional relevance of the brain alterations reported here is supported by an association with processing speed, a widely used index of cognitive function that correlates highly with performance on a broad range of more targeted cognitive tasks (20). Slower processing speed in asthma participants was associated with poorer white matter integrity in the tracts discussed above, in addition to the corticospinal tract, the inferior longitudinal fasciculus, and forceps major, indicative perhaps, of an accelerated decline in cognitive function in asthma when white matter microstructure is compromised.…”

“…Reaction time (RT) in an asthma variant of the Stroop Task( 19) was used to assess processing speed. Processing speed, as indexed by mean RT, is a widely accepted indicator of global cognitive function and has been previously applied in dementia and AD research (20,21), but is not an indicator of dementia per se. Here, processing speed was used to assess the functional consequences associated with dMRI alterations.…”

Validity and Cultural Generalisability of a 5-Minute AI-Based, Computerised Cognitive Assessment in Mild Cognitive Impairment and Alzheimer's Dementia

“…The ICA primarily tests information processing speed (IPS) and engages higher-level visual areas in the brain for semantic processing, i.e., distinguishing animal vs. non-animal images ( 29 ), which is the strongest categorical division represented in the human higher-level visual cortex ( 31 ). IPS underlies many areas of cognitive dysfunction ( 32 , 33 ) and is one of the key subtle, early changes that is slowed down in pre-symptomatic Alzheimer's disease ( 34 ). This is because the speed with which an individual performs a cognitive task is not an isolated function of the processes required in that task, but also a reflection of their ability to rapidly carry out many different types of processing operations.…”

A culturally fair test of processing speed: Construct validity, preliminary normative data, and effects of HIV infection on performance in South African adults.

“…Processing speed (PS), defined as the swiftness with which one is able to complete mental tasks, is a complex cognitive function that is often compromised in neurological disorders, including those associated with HIV infection (Dobryakova, Costa, Wylie, DeLuca, & Genova, 2016; Kore et al, 2015; Lu, Chan, & Lam, 2017). The faster one’s PS, the more quickly information is made available to higher-level cognitive operations (e.g., working memory [WM] and executive functioning [EF]), and the more likely it is that one will perform better on tasks tapping into those operations (Albinet, Boucard, Bouquet, & Audiffren, 2012; Fellows, Byrd, & Morgello, 2014).…”