Diagnosis and treatment for Concentration Deficit Disorder? Sluggish cognitive tempo, sometimes known as Concentration Deficit Disorder, is a syndrome related to (but distinct from) attention deficit hyperactivity disorder (ADHD).
Question: What are the best methods to diagnose and treat Concentration Deficit Disorder?
Do any of the following have scientific support?

Electroencephalography (EEG)
DNA therapy
This answer covers the diagnosis of Sluggish cognitive tempo
While there is debate about its nature (Brooks, 2014, Silva, n.d.) there is a whole issue of the Journal of Abnormal Child Psychology (Vol. 42, Issue 1 - January 2014) devoted to the subject of sluggish cognitive tempo (SCT) and the debate. That issue has renewed interest in the condition (Silva, n.d.).
American Psychological Association (APA) publishes the Diagnostic and Statistical Manual of Mental Disorders (DSM) and is the &quot;go-to&quot; for diagnostic criteria for mental disorders. The latest edition is DSM-5 (APA, 2013). As it stands right now, there is no official definition (as defined by the DSM) of &quot;sluggish cognitive tempo&quot; (SCT) or &quot;concentration deficit disorder&quot; (CDD), but the DSM-5 does mention that concentration deficits frequently occur following mild traumatic brain injury but,

can occur in brain-injured and non-brain-injured populations, including individuals with PTSD (page 280)

and

in individuals with acute stress disorder (pages 284 and 286)

Concentration deficits can also occur in depression.
While the Wikipedia article for &quot;sluggish cognitive tempo&quot; states that

there is no overlap between the official ADHD inattention symptoms [ADHD-I] and the SCT symptoms

there is actually a definite overlap.
The DSM-5 states that for a diagnosis of ADHD-I (emphasis mine on symptom category letters),

Six (or more) of the following symptoms have persisted for at least
6 months to a degree that is inconsistent with developmental level and that negatively impacts directly on social and academic/occupational activities:
Note: The symptoms are not solely a manifestation of oppositional behavior, defiance, hostility, or failure to understand tasks or instructions. For older adolescents and adults (age 17 and older), at least five symptoms are required.
a. Often fails to give close attention to details or makes careless mistakes in schoolwork, at work, or during other activities (e.g., overlooks or misses details, work is inaccurate).
b. Often has difficulty sustaining attention in tasks or play activities (e.g., has difficulty remaining focused during lectures, conversations, or lengthy reading).
c. Often does not seem to listen when spoken to directly (e.g., mind seems elsewhere, even in the absence of any obvious distraction).
d. Often does not follow through on instructions and fails to finish schoolwork, chores, or duties in the workplace (e.g., starts tasks but quickly loses focus and is easily sidetracked).
e. Often has difficulty organizing tasks and activities (e.g., difficulty managing sequential tasks; difficulty keeping materials and belongings in order; messy, disorganized work; has poor time management; fails to meet deadlines).
f. Often avoids, dislikes, or is reluctant to engage in tasks that require sustained mental effort (e.g., schoolwork or homework; for older adolescents and adults, preparing reports, completing forms, reviewing lengthy papers).
g. Often loses things necessary for tasks or activities (e.g., school materials, pencils, books, tools, wallets, keys, papenwork, eyeglasses, mobile telephones).
h. Is often easily distracted by extraneous stimuli (for older adolescents and
adults, may include unrelated thoughts).
i. Is often forgetful in daily activities (e.g., doing chores, running errands; for older adolescents and adults, returning calls, paying bills, keeping appointments).

Citing Becker, et al (2016), Barkley (2018) and Becker &amp; Barkley (2018), the Wikipedia article lists the following for the symptoms of SCT:

Prone to daydreaming DSM criteria b for ADHD-I
Easily confused or mentally foggy
Spacey or inattentive to surroundings DSM criteria b and c for ADHD-I
Mind seems to be elsewhere DSM criteria c for ADHD-I
Stares blankly into space DSM criteria c for ADHD-I
Underactive, slow moving or sluggish
Lethargic or less energetic
Trouble staying awake or alert
Has drowsy or sleepy appearance
Gets lost in own thoughts DSM criteria b, c and h for ADHD-I
Apathetic or withdrawn, less engaged in activities
Loses train of thought or cognitive set
Processes information not as quickly or accurately

While there is an overlap, in criteria, if consensus is achieved for the idea that SCT or CDD exists, there will be a need to officially define a set of criteria which would need to be met, due to the overlap with ADHD-I and the fact that the other symptoms listed can occur with depression.
In the meantime, the

13 SCT symptoms that loaded consistently on an SCT factor as opposed to an ADHD factor

put together by Becker et al. (2014) and copied into Wikipedia (listed above) are all we have at the current time for a diagnosis of SCT.

Although additional measurement work needs to be conducted now that these 13 items have been identified (15-17), it is important to note that parent, teacher, adult self-report, and child self-report ratings scales (18-23), as well as a semistructured clinical interview (24), have been developed that include at least most of these 13 items. Studies using these measures demonstrate that SCT can be reliability assessed, with excellent internal consistency and test-retest reliability, and moderate interrater reliability (14). (Becker &amp; Barkley (2018))

On top of this, whilst research indicates SCT is associated with ADHD-I,

findings show that SCT is even more prevalent in autism. SCT is most common when autism and ADHD co-occur. Because autism without ADHD is rare (whereas ADHD without autism is not), it is important to assess both SCT and ADHD in children referred for autism evaluations and rule-out autism in children referred for ADHD. SCT may be another neurocognitive problem shared by children with autism and children with ADHD in need of assessment and intervention (Mayes, et al. 2020).

References
APA. (2013). Diagnostic and statistical manual of mental disorders (DSM-5®). American Psychiatric Pub. https://www.psychiatry.org/psychiatrists/practice/dsm
Barkley, R. A. (2018). Barkley Sluggish Cognitive Tempo Scale — Children and Adolescents (BSCTS-CA). Guilford Publications.
Becker, S. P., Leopold, D. R., Burns, G. L., Jarrett, M. A., Langberg, J. M., Marshall, S. A., ... &amp; Willcutt, E. G. (2016). The internal, external, and diagnostic validity of sluggish cognitive tempo: A meta-analysis and critical review. Journal of the American Academy of Child &amp; Adolescent Psychiatry, 55(3), 163-178. https://doi.org/10.1016/j.jaac.2015.12.006
Becker, S. &amp; Barkley, R. A. (2018). Sluggish cognitive tempo (Chapter 15) Banaschewski, T., Coghill, D., &amp; Zuddas, A. (Eds.). Oxford Textbook of Attention Deficit Hyperactivity Disorder (pp.147-153). Oxford University Press. https://www.researchgate.net/publication/292148331_Sluggish_cognitive_tempo
Brooks, M. (2014). Sluggish Cognitive Tempo a Distinct Attention Disorder? Medscape Psychiatry News https://www.medscape.com/viewarticle/819838
Mayes, S. D., Calhoun, S. L., &amp; Waschbusch, D. A. (2020). Sluggish cognitive tempo in autism, ADHD, and neurotypical child samples. Research in Autism Spectrum Disorders, 79, 101678. https://doi.org/10.1016/j.rasd.2020.101678
Silva, M. (n.d.). A Fuzzy Debate About A Foggy Condition Cincinnati Children's Hospital https://www.cincinnatichildrens.org/professional/resources/research-horizons/archives/2015/summer/sluggish-cognitive-tempo