Table 1:

Results of the combination MR Spectroscopy/DTI*

Group IV
    1+++++true pos.NA+
    2+++true pos.+
    3+++++true pos.
    4+++++true pos.+
    5+++++true pos.++
    6+++true pos.+
    7+++++true pos.++
Group III
    1+++++true pos.+
    2++++false pos.NA+
    3true neg.
    4true neg.++
    5+true neg.+
    6true neg.++
    7+true neg.NA+
Group II
    1true neg.+
    2true neg.
    3++true neg.+
    4true neg.
  • Note:—MRS indicates MR spectroscopy; UMN, upper motor neuron; TMS, transcranial magnetic stimulation; DENERV, denervation; true pos., true-positive; false pos., false positive; true neg., true negative; NA, not applicable; DTI, diffusion tensor imaging.

  • * ++ for MRS indicates NAA/Cho reduction beyond double SD; + beyond single SD. For DTI, ++ indicates 2 or more regions with FA below double SD; + just 1 region, respectively. −indicates a negative result. Reduction beyond the single SD threshold for MRS and beyond the double SD threshold in 1 region for DTI is regarded as a pathologic result of the MRS/DTI combination; discordance is graded as negative. Note that patient III/1 had primary lateral sclerosis but was subgrouped into the “clinically possible” group (III) due to his initial EE rating. DTI and MRS concurrently are false-positive in 1 patient with lower motor neuron involvement only (patient III/2).

  • Clinical evidence for upper motor neuron involvement.

  • Pathologic central conduction times in transcranial magnetic stimulation.

  • § Presence or absence of generalized denervation.