Interictal Cognitive Deficits in Migraine Sufferers: A Meta-Analysis.

While a significant proportion of the population suffer from migraine, the existing research literature does not provide a clear indication as to whether migraineurs experience objective cognitive deficits outside of acute migraine attacks. This meta-analysis was conducted to investigate which cognitive domains if any were affected by migraine, by synthesising the existing research quantitatively. The meta-analysis was prospectively registered with the PROSPERO International prospective register of systematic reviews (registration no.: CRD42019134138). A search of the electronic databases PubMed, Ovid MEDLINE, and PsycINFO was conducted for journal articles published between January 1980 and January 2020. Seventeen studies met the inclusion criteria, allowing for the calculation of pooled effect sizes between migraineurs (with and without aura) and healthy controls in the several cognitive domains. During the interictal period, migraineurs demonstrated a moderate, negative effect on complex attention immediate and delayed memory, spatial cognition, and executive functioning. This effect was not attributable to migraine history, attack frequency, or participant age. However, the lack of performance validity testing, and limited data on mood symptomatology and migraine medication use in the included studies may be confounds potentially overestimating the magnitude of effect. Comparison with a clinical control group, which may have accounted for some these extraneous variables, was unable to be conducted. Recommendations for comprehensive future neuropsychological research are provided.

An analysis of distinct navigational domains and topographical disorientation syndromes in ABI: A meta-analysis.

Topographical disorientation is the impairment or inability to successfully navigate in three-dimensional space. Differing topographical disorientation syndromes have been associated with distinct lesion sites in the acquired brain injury (ABI) literature. This meta-analysis attempted to investigate the relationship between lesion location and dysfunctions in specific navigational abilities resulting in topographical disorientation in individuals with ABI, as measured by their performance on experimental and neuropsychological tests. It was expected that focal lesions would be associated with a specific navigational deficit in one ability, with relative sparing of other navigational abilities. Twenty-six papers met the inclusion criteria for the analysis. Results indicated that ABI populations performed worse on all measures of navigation, with moderate to large effect sizes. Dysfunctions in three core navigational skills were consistent with the available lesion studies: a feature/landmark processing unit, a spatial processing unit, and a spatial/feature binding and associative learning unit. A sequential processing model was created to attempt to best represent the transfer of information between these units and the process by which navigational knowledge is generated. The model was then used to assess the validity of existing models of navigation and topographical disorientation.

Cognitive and emotional deficits in chronic alcoholics: a role for the cerebellum?

It is now widely accepted that in addition to motor coordination, the cerebellum is also involved in the modulation of cognitive and affective processes. Despite alcoholic cerebellar degeneration (ACD) being the most common form of cerebellar disorder, little systematic investigation of cerebellar-mediated cognitive and affective deficits has occurred in chronic alcoholics. Forty-nine chronic alcoholics and 29 healthy control participants underwent testing of cognitive and affective function, along with measurement of cerebellar ataxia using the International Cooperative Ataxia Rating Scale (Trouillas et al., Journal of the Neurological Sciences 145:205-11, 1997). The alcoholic group demonstrated significantly poorer performance as compared to the control group in a number of domains, including visuospatial and language skills, psychomotor speed, new learning and memory, executive functioning, and emotional regulation and affect processing. There were no differences between the alcoholic and control groups in immediate attention and working memory abilities. Years of heavy drinking and total period of abstinence were found to be the best predictors of cognitive and emotional function in the alcoholic group. After accounting for alcohol chronicity, there was still a relationship between the degree of clinical signs of ACD and some areas of cognitive and emotional functioning, including language, executive functioning, processing speed and affect processing. The results suggest that some of the cognitive and affective deficits observed in chronic alcoholics may be mediated, at least in part, by cerebellar dysfunction. These findings add support to the theory of disruption to bidirectional cerebro-cerebellar circuitry underlying cognitive and affective deficits in chronic alcoholics.

Characterization of cerebellar ataxia in chronic alcoholics using the International Cooperative Ataxia Rating Scale (ICARS).

BACKGROUND: Alcoholism is the most common cause of cerebellar dysfunction, yet estimates of the incidence of alcoholic cerebellar degeneration (ACD) vary greatly, with differences in methodologies contributing to these disparate findings. This study set out to characterize the frequency and pattern of clinical signs of ACD in an alcoholic group using the International Cooperative Ataxia Rating Scale (ICARS). METHODS: We compared the performance of 49 alcoholics and 29 control participants. The relative contributions of demographic and alcohol consumption variables to ICARS scores in the alcoholic group were also examined. RESULTS: The alcoholic group demonstrated significantly poorer performance on all of the ICARS subscales as compared with the control group. Within the alcoholic group, performance was more impaired on the speech scale than on all of the other scales, except the lower limb component of the kinetic scale, and less impaired on the oculomotor scale compared with all other scales. Years of heavy drinking and lifetime alcohol consumption correlated with total ICARS scores; however, maximum daily consumption was actually negatively correlated with ICARS scores. Of the alcohol history variables, years of heavy drinking was the best predictor of total ICARS scores, making a 19% unique contribution, followed by the period of abstinence from alcohol, which uniquely contributed 7% of the variance. There were high correlations between age and male gender and the alcohol consumption variables; however, age and gender were still found to uniquely contribute 5 and 7% respectively to the variance in total ICARS scores. CONCLUSIONS: ACD may affect up to two-thirds of chronic alcoholics. Assessing the number of years an individual has been drinking beyond a certain threshold can give a good indication of the likelihood of ACD. Age, gender, and the source of the clinical sample may significantly contribute to the prevalence of ACD and require further detailed investigation.