Microscopy
Diagnosis is usually made by identifying proglottid segments, or characteristic eggs in the faeces. Eggs are usually numerous and can be demonstrated without concentration techniques. Morphologic comparison with other intestinal parasites may be employed as a further diagnostic approach.These simple diagnostic techniques are able to identify the nature of the infection to the genus level, which is usually sufficient in a clinical setting. Though it is difficult to identify the eggs or proglottids to the species level, the distinction is of little clinical importance because - like most adult tapeworms in the intestine - all members of the genus respond to the same treatments. Treatment may distort morphological features of expelled pathogen tissues and complicate subsequent morphological diagnosis attempts. Genetic identification
When the exact species need be determined (e.g. in epidemiological studies), restriction fragment length polymorphisms can be effectively used. PCR can be performed on samples of purified eggs, or on native fecal samples following sonication of the eggs to release their contents. Molecular identification is currently generally only used in research. Radiography
A potential diagnostic tool and treatment is the contrast medium gastrografin which, when introduced into the duodenum, allows both visualization of the parasite, and has also been shown to cause detachment and passing of the whole parasite. Prevention
Ingestion of raw freshwater fish should be avoided. Adequate cooking or freezing of freshwater fish will destroy the encysted fish tapeworm larvae. Fish that is thoroughly cooked, brined, or frozen at -10 °C for 24–48 hours can also be consumed without risk of D. latum infection.
Cognitive deficit is an inclusive term to describe any characteristic that acts as a barrier to the cognition process.The term may describe

deficits in overall intelligence (as with intellectual disabilities),
specific and restricted deficits in cognitive abilities (such as in learning disorders like dyslexia),
neuropsychological deficits (such as in attention, working memory or executive function),
or it may describe drug-induced impairment in cognition and memory (such as that seen with alcohol, glucocorticoids, and the benzodiazepines.) Cause
It usually refers to a durable characteristic, as opposed to altered level of consciousness, which may be acute and reversible. Cognitive deficits may be inborn or caused by environmental factors such as brain injuries, neurological disorders, or mental illness. Screening
Screening for cognitive impairment in those over the age of 65 without symptoms is of unclear benefit versus harm as of 2020. In a large population-based cohort study included 579,710 66-year-old adults who were followed for a total of 3,870,293 person-years (average 6.68 ± 1.33 years per person), subjective cognitive decline was significantly associated with an increased risk of subsequent dementia. Treatment
Older people with cognitive impairment appear to improve somewhat with light therapy. Other findings
Although one would expect cognitive decline to have major effects on job performance, it seems that there is little to no correlation of health with job performance. With the exception of cognitive-dependent jobs such as air-traffic controller, professional athlete, or other elite jobs, age does not seem to impact ones job performance. This obviously conflicts with cognitive tests given, so the matter has been researched further.